Jason Fischbach, Agriculture Agent with Ashland and Bayfield Counties visits with Eric Wolske, PhD candidate, at the University of Illinois about growing currants and market opportunities.
Cutting Edge: In Search of New Crops For Wisconsin
Episode 21: Currants
Recorded March 25, 2021
Eric Wolske, JASON FISCHBACH
JASON FISCHBACH 00:00
This is a podcast about new crops. You’re gonna love it. Join us on the cutting edge, a podcast in search of new crops for Wisconsin.
Eric Wolske 00:09
I think they’re a great crop. I think they have huge potential for the health food market and just for overall taste, and we just the biggest the biggest hold back and setback we have right now is that nobody knows what a black currant is.
JASON FISCHBACH 00:47
Welcome to the cutting edge a podcast in search of new crops for Wisconsin. I’m Jason Fischbach, the agriculture agent for Ashland and Bayfield counties. And today’s episode is all about currants, black currants, white currents, maybe pink currants and red currants. And with me is Eric Wolske. Do I have that pronunciation right, Eric?
Eric Wolske 01:07
JASON FISCHBACH 01:07
With the University of Illinois. And I think it’s gonna be a great episode as we talk through currants because it’s a crop that can grow phenomenally well, in the upper Midwest, the only thing holding us back really are markets and maybe some historical reticence to grow currants because of white pine blister rust, but we’ll get into all that. So, Eric, welcome. And if you could introduce yourself and how you’ve been involved with currants over the years.
Eric Wolske 01:31
Hi, yeah, so yeah, Eric Wolske. I’m a PhD candidate, at University of Illinois. I’m in my hopefully final year of research here after a pretty long time, studying currants. I started off looking at the shade tolerance occurrence with my masters in the hopes of them being able to get included into agroforestry systems. And we found that they respond very well to shade that they can still produce good sizeable yields without too much issues from disease. And so from there, I moved on to my PhD work, which was exploring then 24 varieties of black currants, red currants, and white currants and a pink currant. And so we grow those across the state and Wisconsin and have the ones in Champagne are grown both open sun and under 65% shade netting. So we can kind of compare and say yes, all currants are good for shade or only these select varieties are or these select traits of these varieties are what make them shade tolerant. So I’m concluding that research this year, or at least the main point of that which was, this will be year five for them. So we should have pretty good baseline data at least to start off with for recommendations for growers and producers and even for researchers looking into breeding efforts.
JASON FISCHBACH 03:03
Got it. Did I see you’ve got a Twitter handle something about jam master or currant jam or?
Eric Wolske 03:09
JASON FISCHBACH 03:10
Eric Wolske 03:12
JASON FISCHBACH 03:13
Do you make currant jams and jellies too?
Eric Wolske 03:15
I actually leave that to my mom, I drop off you know baskets for her she made a good processed jam this year. I actually, my specialty is the lecoultre ciders and hard seltzers market. So I am a avid cassis maker, Creme de cassis. Yeah, so actually, I came from grapes. That was what I did after I got my undergrad and plantsville science down in Southern Illinois University Carbondale is I went and worked at a couple vineyards, fell in love with growing wine grapes and came up here wanting to kind of do something similar. And they were like, okay, you’ll be our currant guy. And I only knew currants from the standpoint of this wine has a note of blackcurrant, you know, and peppers or something. And so I had never actually even tasted a black currant until after my first year of school.
JASON FISCHBACH 04:10
So we tend to start out our episodes our podcast episodes talking about markets for some of these new and emerging crops. And certainly, currants are not a new crop. They’ve been around forever. So can you just give us an overview of where things are at for currant markets in the US and, you know, maybe the size or state of the industry in the upper Midwest, Wisconsin, Illinois, you know, maybe in Minnesota, Iowa, and where you see things going and what might get us there.
Eric Wolske 04:39
Yeah, so yeah, as you as you mentioned, I mean currants have been around for the past couple 100 years as a production crop in Europe. And they were here, they were they were brought over and the 1800s. So early America had currants, and well into the early 1900s before they were removed from the White Pine blister rust, The biggest I think, start kick you know kick up kickstart of the newest round of currant was came from Greg Quinn out in New York, really pushing for currant production in the eastern US. And he started currant seed and got got the ban lifted and currants started becoming a little more of a marketable product. On the health food front of here is this crop that is high in vitamin C, full of mineral nutrients. And if you have a cough drink some of this and kind of same way the elderberry market is currently going right now, over in Missouri that you see. In the Midwest, however, it is seemingly, and this, you might have a better idea of this than I do about it’s it’s seemingly that coming from Wisconsin, that was more or less the, my at least from my standpoint, it seems to be the regional epicenter of currant production in the Midwest. And we, at the U of I got hooked on it from the agroforestry perspective, and as a shade tolerant crop. And so we tried trialing those in central Illinois, there are a few other currant growers in Illinois, there’s a few more in Wisconsin, but we haven’t really seen anything of sizeable scale, certainly not like what you see in Europe, where you can find a 200 acre currant field, like you can find our corn and bean fields right now. The you know, the biggest that I’ve seen is about 20 acres in any of our states. So it’s still a very limited market. And some states, like Michigan still have bans on what cultivars can be allowed to grow. And so that’s also allowing a lot of restriction from what would be considered the, you know, major Midwest fruit production areas. And so I think, with the cultivars coming out of some of the new variants from Canada from McGinnis Berry Crops, they seem to be way better producers and way more resistant to many of the diseases that have put off a lot of farmers. And a lot of farmers have planted them out and then they get smacked with powdery mildew. And the I think the initial selling point for a lot of the a lot of currants was that this is a, in the fruit world would be considered a very low spray fruit, compared to something like apples or grapes. And I think when you start getting diseases like powdery mildew that require a fair amount of sprays to kind of keep controlled. It’s been a little bit more of a off putting, but I think as we get more varieties released that are capable of handling, you know, being resistant to the diseases yielding well and are better suited. So like McGinnis has a stated purpose of breeding for North American palates, which tends to mean higher sugar content a little bit lower acidity.
JASON FISCHBACH 08:03
Eric Wolske 08:04
We’re all there on that, I think.
JASON FISCHBACH 08:06
Right. Well, let’s come back to the disease issues, because that’s an interesting one, especially as we see how it plays out across Wisconsin, in some of our research too. But so for our listeners that maybe aren’t all that familiar with currants, there’s black currants, white currants, pink currants, red currants, are they all the same species? The same thing?
Eric Wolske 08:25
Yes, and no. Black currants are their own separate species. Black currents are Ribes nigrum. Included in black currants are also green currents, which I have no knowledge of, other than the fact that they they have them they grow those in Scandinavia. And those are a type of Ribes nigrum. Whereas the red, white and pink currants are all Ribes rubrum. So they all are in their own species with just different levelling, levels of pigments in their fruit ranging from red to clear white.
JASON FISCHBACH 08:57
And I’m one of those American consumers I’ll gobble up the red and the pink and the white. And I’ll spit out the black currants as fast as I can. So what is it about those black currants that it that is just tart, they’re almost astringent almost wants to dry out your mouth?
Eric Wolske 09:12
Yeah, the dryness comes from those those health benefits. I mean, you can’t really even compare, in my opinion, a red and white currant to a black currant in terms of health value. The red and white currents are falling into a, they’re still healthy. I don’t want to say that they’re not healthy, they still have a lot of vitamin C and a lot of vitamin A and some good uses there. But the black currants just are far and away. It’s those anthocyanins that have all the antioxidant compounds. That is what they, I mean they, they are better than blueberries on which we kind of I think Americans like this to set the standard at blueberries. So it’s it’s a high vitamin C it’s they’re healthy, they taste healthy.
JASON FISCHBACH 10:00
Eric Wolske 10:00
I guess would be the best description.
JASON FISCHBACH 10:03
If people have eaten black currants, to me, because the plants have been more widely available as Titania black currants. But that’s just just scratching the surface of all the different varieties. Right? I mean, can you talk a little bit more about maybe even some of the breeding programs or, or the if you’ve seen big differences among the varieties of black currants in flavor, astringency, all that stuff.
Eric Wolske 10:25
Yeah, so we, so I guess to start off, I would back up that Consort, Coronet and Crusader were the first releases out of North America for black currants, specifically for resistance to the disease that got them banned, white pine blister rust, and they are considered a horrible berry, Europe did not want them. And they get, when you compare them in terms of mineral nutrient and anthocyanins, like the the health benefit compounds, they blow the other black currants out of the water, I mean, they they are, the Consort is probably arguably one of the healthiest berries out there in terms of full nutritional content. But it means it’s not a not a good flavored berry for really for processed goods. And so then they bred from that one, Titania, and that was bred to have the European flavors that they want with the resistance that the Consort had. And Titania is a good one, it produces well, but it’s still on the what would be considered a blander scale. It’s not a top preference. And so there’s been some breeding research, I believe out of Oregon State or Washington State, somewhere over there in the West Coast, they’re looking at some varieties that I haven’t, I haven’t done much work on. There’s ones like Chime and a few other varieties that are listed as being pretty good flavors. The main ones that we’ve been testing out have been the McGinnis varieties, and those ones I would consider to be getting close. Some of those get close into range of being into a blueberry territory where you could actually eat them fresh out of a bowl. A few of those varieties I brought to, you know, family gatherings pre COVID. And had the little kids would would eat the whole bowl before the before the adults could even get to it, which I think is a sign of palatability.
JASON FISCHBACH 12:24
Eric Wolske 12:26
And it’s the sugar content, I think is going up, the the acidity kind of goes down a little bit. We’re going to be analyzing some of that data here soon to get an idea of you know, why are these ones better? And we’ve done a little bit of taste testings, two years previously, on could you know sort of what consumers are are liking with the blackcurrants, both with juice and with fresh berries. And we’re finding that there are some varieties that are kind of standing out that people are, they they taste it for the first you know, their first taste of blackcurrants and they’re like, well, that’s something, I could drink that.
JASON FISCHBACH 13:02
Yeah. So that’s been our experience here in Bayfield County where we have a grower that I know a couple, three, four acres, also blueberry growers. So, it works well with their harvesting and field equipment to run a blueberry picker over it. And they did Ben Lamond Ben Sarek to compliment Titania in terms of the maturity. But it’s it’s been almost exclusively a processing fruit. It’s used to make a cork by a winery or it’s used by, you know, the few homeowners that like I shouldn’t say a few but there are folks maybe with some cultural heritage or something that have had black currant jam or jelly in their background. And so they’re buying that to make their jams and jellies but it’s never really been, at least our experience yet, a fresh eating fresh fruit black currants, always a processed fruit. But it sounds like maybe that’s changing. Do you think that’s the industry as breeders wants the industry to go that way? It’s more fresh-eating than processing or is the goal still more the vision to be more of a processing fruit for black currants?
Eric Wolske 14:04
In my mind, the appeal to the black currant is it can be machine harvested and machine pruned. And the advantages of that then come into a processed food market and less of a fresh eating. I think they’re, I think the market would be more towards a frozen berry. You know, it’s something that you can add to smoothies or you can pull out and you can add into your confectionaries, into your baked goods. That would be more, I think the berry route. But I still think that in terms of gross sales in terms of how much a farmer could offload, you really can’t be processed goods. And I think historically processing is, I think if I don’t have the numbers in front of me, I want to say something like 90% of, of black currants grown in Europe go towards processing. It’s either juice or jams and jellies and and a very small fragment of that then goes into fresh eating. But it’s, it’s seems like I think there’s a potential for them to be a fresh eating fruit. It’s just, the fresh market fruits are kind of everyone already has their mind made up about what they want to eat when they go the fresh, you know, the fresh berry market and they want their strawberries, they want their blueberries, they want their raspberries, maybe a blackberry.
JASON FISCHBACH 15:22
And they’re so incredibly sweet. It’s so hard to get people to eat anything but that.
Eric Wolske 15:27
JASON FISCHBACH 15:29
So on the red, pink and whites. I’ve grown them outside, I’m also growing red in our high tunnel, you know? And to me, it’s night and day and it’s so can we first degrees just crossed white currents off the list entirely? Or is Blanca. That’s the only variety I’ve seen that. You can maybe handpick it, but like Imperial and what’s the, what are those other ones? They look like caviar.
Eric Wolske 15:56
Yeah, oh, they come up super small. White Imperial is, it makes me cry. Might field crew when we go out there for harvesting. They, we kind of have jokes about, you know? Well, one of the jokes was, well, you’re such a white currant, as a as a way of showing dismay and disgust with somebody and their actions because they they tend to just squish off the plant. And you just, you don’t it’s really hard. And it’s hard to measure. It’s hard to for me as the researcher, I’m trying to get berry size and stuff. And it’s, they’re all mush, so what’s, you know, I have a bag of preserves, not a bag of berries.
JASON FISCHBACH 16:36
And three hours later you move on to your second Bush to pick it.
Eric Wolske 16:41
That’s exactly it. Yeah, they don’t really come off nicely. I do. I do. I do wonder. And you’ve you’ve provided pictures of this. Of trellised options. I I do think that there might be a potential for maybe on trellis, you might be able to get them in a better format. But white currents are probably the biggest here is I shed when I go out into my field.
JASON FISCHBACH 17:05
Yeah. Okay. So the pink, is our only option pink champagne?
Eric Wolske 17:10
That’s as far as I know, I had, I actually was just sent over a few other varieties that I’m kind of perusing through to see. But as of right now pink champagne is, is sort of the standard. And it’s, for me, it’s kind of crazy, because pink champagne has been around since I want to, I want to say that one was bred in the 1800s, maybe, or early 1900s. So it’s almost like coming from grapes. It’s kind of exciting, you know, to get back to that territory of historical fruits, fruits that, you know, my great great grandparents might have tasted at a market at one day.
JASON FISCHBACH 17:43
Yeah, right. Right. And I’ve seen that on trellis outside too. And it’s it’s very doable. Much bigger cluster sizes, easier to pick, and the berries are big, and they’re really sweet people like pink currants it’s just been.
Eric Wolske 17:56
JASON FISCHBACH 17:56
For the pink champagne. It’s just if you grow it as, in a shrub form, it gets overgrown because it is pretty vigorous, it just kind of gets to be a nightmare to pick too, but. Okay, so that brings us to red currants. Can you tell us more about, kind of red currants and that to me, if I understand it, right is grown more widely, both in Europe and even more so maybe even in the US?
Eric Wolske 18:18
Yeah, so red currants, they have a little bit better of a market. They can be frozen pretty well, they have a little bit better, curb appeal, you might say they tend to hold their their fruit size and, and stay pretty well in the fridge. So you can sell them as sort of a fresh market, sort of plant. They also have released some cultivars with thicker skins, that, at least in Europe, they are doing a fairly good job of machine harvesting, which I think is very appealing to farmers. But they also do pretty well I think on trellis, when I went to when I was over in the Netherlands they had trellised red currants that looked beautiful. And I think you sent over yeah, that picture of a cherry or wild or something what, Rovada maybe?
JASON FISCHBACH 19:09
Yep, Revada. I’m working on my publication, extension publication that shows you know, it basically trying to mimic what they’re doing in Europe, in the high tunnel greenhouse, but it is night and day. I mean, they’re huge. They’re almost like grape clusters that get so big. So I think that whether it pays for that high tunnel structure is a whole other question when you can grow tomatoes or something else in there, but still, it’s an amazing fruit, anything else to say on red currents in terms of varieties, or?
Eric Wolske 19:39
I just finally pulled up my recommended cultivars list here, and this was based on maybe last from two years ago, so I haven’t fully updated from last year’s data but I did put down that with sprays. The Primus was a good white currant cultivar, it produced fruit that was well enough in my opinion. But we’ve had tremendous issues with powdery mildew this year, and the powdery mildew, it was the first time I’ve seen powdery mildew on fruit. Actually, well powdery mildew for blackcurrants tends to just stick the leaves and causes foliar damage which causes plant health damage, which reduces your yields. But this was the first time I actually saw it jump to the fruit and actually have fruit damage to the plants. But, if you can control that, which powdery mildew for the most part can be controlled organically with the correct sprays at the correct times. It wasn’t a bad one. In terms of red currants. I have Cherry, DEP van, cherry and DEP van listed as sort of my top ones. The cherry currant, red currant, I was amazed with how easy those ones were for harvesting, they just kind of, you could pull those off. They were nice big clusters, even just in shrub form. And so I found those ones to be really exciting. We were usually pretty happy when we got to that for the Cherry’s. It was oh, that’s a Cherry treatment we’re harvesting and Yay.
JASON FISCHBACH 21:03
Yeah, right. My turn I get to do this one.
Eric Wolske 21:06
Yeah, that’s exactly it.
JASON FISCHBACH 21:09
I’ll have to try that one. We only have Rovada on the high tunnel mainly because of its resistance to powdery mildew.
Eric Wolske 21:15
JASON FISCHBACH 21:16
But is Cherry resistant to it. You know?
Eric Wolske 21:20
Yes. Or at least that’s why I’ll have to go through and compile some more data on that one. But at least it was two years ago, it was resistant.
JASON FISCHBACH 21:29
Okay, so what’s your take? Do you think fresh eating red currants are a market opportunity for growers? You know, CSA pick your own farms?
Eric Wolske 21:38
I think so. I think it’s going to take some time to get Americans warmed up to currants, which is, I think, a whole discussion in itself. But I do think that if, if they if they were I do think a lot of people enjoy them. They do enjoy eating them. They enjoy baking with them. They also aren’t, they’re not horrible for jams and jellies and preserves kind of thing. They do pretty well for that too. So they just don’t tend to have quite as the versatility that the blackcurrants do, they don’t juice well. So or at least you’d never, the times that I’ve juiced them has been minimal you know quality at best. There’s something there. The local brewery did make a red currant beer, a red currant wheat, and it turned out pretty good. I’ve brewed with with red currants before and they’ve turned out actually not too bad. The flavors are more reminiscent of like a strawberry- raspberry with a little more sour kick to them. A lot more sour kick to them, I guess I’d say. And the, one of the major puree markets for brewers, winemakers, everything else is out of Oregon. And they do sell a red currant puree. So I think that’s at least a sign that, at least they’re finding a market worthy of the time, the effort, and the cost to make that product.
JASON FISCHBACH 22:13
Well, let’s shift to your research. I think it’s fascinating the work that you guys are doing with these agroforestry systems and taking advantage of the shade tolerant properties. So maybe just talk through what what you’ve been doing what you’re finding and maybe even how folks can read up on the results after they listen to the podcast.
Eric Wolske 23:23
Yeah, so hopefully, publications will start rolling out from this this fall and next year. I do have some publications that we’re working on for my master’s work. I do have one publication about the shade tolerance of blackcurrants, we found that 65% shading was completely fine for the plants with with with no issues in terms of production, growth. A slight increase in disease, that that study was done with Consort and Consort does get powdery mildew damage and powdery mildew does like shaded environments. So, we you know, the main takeaway from that was, we’re good up to 65% we had an 85% shade treatment where the only loss we really, really saw consistently through the years was a slight decrease in sugar one of the years but for the most part the plants actually seem to do okay, it just started to yield less, we had about a 25% reduction in yields and the 85% shading and you start to lose some figure in the plants themselves. So that trial though, was in the same site that has what we call the woody perennial polyculture project. A lot of peas in that one. And that one involved planting of chestnuts, currants, hazelnuts, raspberries and apples. And we planted those out into blocks to compare with corn and bean standard conventional rotations and we found that one, at least as of year 9 or 10, agroforestry systems do not out yield corn and bean systems, which was more or less what our thoughts were to begin with. But we did find that we, we, we reduced the amount of nitrogen leaching tremendously. Even though we were, we applied nitrogen the same to both the corn and beans so we were actually fertilizing our agroforestry systems excessively you might say from.
JASON FISCHBACH 23:52
That is an incredible amount.
Eric Wolske 25:30
Yes, 100 pounds of nitrogen per year, per acre. Yeah, so we were throwing down nitrogen and the that, that still the plants soak it up, we had we had hay in between the rows that we were bailing. And so I think that also helps quite a bit in terms of sort of soaking up any of that nitrogen. But then underneath that you have all those tree roots. And so those systems have been working pretty well. The currants inside of those are in the rows of the chestnuts and are still producing like crazy, they still grow very well.
JASON FISCHBACH 26:05
So it’s you said, up to 65% shade, can you kind of give us a visual of what that is like?
Eric Wolske 26:13
65% shade would be maybe like under more of like a dappled apple orchard, is kind of what I would say, you know, so sort of what you might find at the base of an apple tree or a chestnut tree for that matter.
JASON FISCHBACH 26:27
Is that shady enough that it would slow down some of the weed growth?
Eric Wolske 26:33
I wish. Yeah, no, we I think we found that for the most part. Okay, so I take that back, it does seem to reduce weeds a little bit. But it’s it more or less, it just shifts the weed species you have. So we found that a little bit more of some of like the smaller grass species coming through a lot more of like henbit and stuff like that, which aren’t quite as big of an issue. And then the other issue though, with that is that when you have species like the pig weeds and the amaranth species, or like mares tail, they tend to get a good footing, they tend to germinate. And then they tend to bolt to try to reach the top. So you get these long, tall, spindly things inside inside your rows. And so yeah, unfortunately, it’s still not enough. The 85% shade netting is when we started, I think noticing that the weeds were staying out that it was getting to the heavier shade level. And so, you know, arguably by that point, that might be something. And the other difference. Another consideration that we had to make sure that we were clear about when we wrote the papers is that these were shade nettings. And shade netting is not the same as as what you get in sunlight. Sunlight is dappled shade. And so you might get a heavy shade for a moment. And then your plants might all of a sudden get full sunlight for another hour. And then they go back and they go back and forth. And so the plants response in that way, could be incredibly different than what we had measured from a uniform shading environment. And so I would actually say ours compares, arguably more to what would be like the semi transparent agrivoltaics that’s been going on, the photovoltaics and growing plants underneath those during the photovoltaics on greenhouses. So that might be a little more of a fair comparison. But the, even just the currants that are growing under the chestnuts right now, we’re finding are doing incredibly well. And give us hope that yeah, this this, this should work pretty well. And I would say that leads into sort of the variety trial that we have going on, in that it’s, we have those plans that are 65% shade. So you’re like okay, this is our max that we feel comfortable with. And we’ve been testing those out. And for the most part most most of the blackcurrants are doing well, but it seems to be more of a, if they do very well under full sun, they just still do very well under shade. And so it’s more of just a plant that can produce four pounds of berries in a season might produce three pounds of berries in a season under shade, but that’s still going to be you know more than enough berries than what we were wanting or something like that. So…
JASON FISCHBACH 29:29
Right or more than you would grow, than you would grow with nothing.
Eric Wolske 29:33
JASON FISCHBACH 29:38
Okay, so that that chestnut currant system or really you could, you know, add in your shade tree or you know walnut or whatever, maybe, well maybe not walnut, does it, an currants grow under walnut, do you know?
Eric Wolske 29:54
So I have a walnut tree in my backyard, and I planted out currants, gooseberries and elderberries underneath it, so far they’re all still alive. So I guess we’ll have to keep further testing that hypothesis but black walnut, you know, plants and resistance to that it seems to be fairly variable. And so that would, I would, I feel more comfortable claiming that it’s okay, if I had a nice little trial I could do where I could put, you know, some in full sun, some in the walnuts shade and then I could.
JASON FISCHBACH 30:31
Sure. But the idea is you’ve got an overstory crop and you’ve got the understory crop. So how would you harvest mechanically, the currants? So are they just offset enough from the trunk that you could get a straddle harvester over the row, or is or is the chestnut literally right in the row with the currant?
Eric Wolske 30:48
So this this was our first planting of this sort in Illinois and with our research trials, and that wasn’t really a consideration at first. Machine harvesters weren’t really talked about item for the blackcurrants in our research group and so we end up moving further on planted out one more trial of blackcurrants, a much larger trial with blackcurrants, chestnuts, various tree species, and ran into the same issue and at that point that was about a 38 acre planting. And so that was outside the realm of we’ll just send out some undergrads to harvest and plan some grad students to harvest currants. And it turned into the realm of we need a harvester because we won’t get these harvested. And that is when we discovered the major restrictions of planting currants in the same row as your tree species. The machine harvesters do not there are some that do weaving that you can actually manually push it kind of into the rows and manually pull it back out with with your hydraulics. So that first side, what we do now is we developed a side catchment system and we use hydraulic shakers that you traditionally see maybe on olives or blueberries. And we run those pneumatics down the side with the catchment systems pulled by a small Kubota and a small Kubota tractor and a side by side UTV. And that tends to do pretty well, we have found that, I mean, it increases, I don’t have those numbers in front of me either that, we have found that that does a really good job of speeding up the harvesting process. And the overall just the backs and the arms of all the harvesters and the crew, that’s a part of it. And so that’s not a bad option. And that’s that’s with plants, those trees were planted on, I want to say 10 or 10 or 20 foot spacing in between like it within row. And we’re able to kind of move right along just fine. And we can move around those trees with no issues. For the machine harvester. I guess in a way for the black currant industry, we were fortunate enough to have bad success rate with the chestnuts that we planted out. And so most of the chestnuts then ended up getting removed. And so we have these nice long strips of blackcurrants that were allowed to, that we can harvest just fine from and on that site, we’re replanting now with pecans in between those rows. And so that then allows us about 12 foot spacing on either side of the plants, the current plants that we can then run the harvester through without affecting the trees and without having to do any of the weaving. And so I think going forward for any recommendations I give to any growers, it’s if you plan on machine harvesting, you need to have 12 foot rows from the nearest tree or allow those tree spacings within the row to go into more of the 80 foot 100 foot kind of you know, way broad, you know broader range. And then I think you could do currants, you know pretty well to just weaving with with the machine harvester.
JASON FISCHBACH 34:05
So we we tried out a bunch of straddle type harvesters with our hazelnut project. And we tried the Joanna-4 aronia harvester, which has got that offset picking head that is designed to pick half the plant at a time and it basically just knifes right through the plant, bends the stems over and shakes them off. And I wonder even with chestnuts or walnuts or whatever in the row. I would think you could nose that thing in there and just go right by the edge of the chestnut and then come back on the other side of the row. And then there’s two passes per row which isn’t ideal, but.
Eric Wolske 34:41
Yeah, maybe that’s that’s a way you could accomodate. Yeah, we use a Joanna-3 and it’s about the same way. And what we were able to do was you would just have somebody that would be walking the row while the other people are on the harvester on the tractor and they would manually move the that guide arm around the trees and our trees, were still within year three year four so you could kind of bend those trees too, and we were able to make it work as long as the currents were within, you know, not within six ish feet of the base of the tree. And because outside of that, then I mean, you would be able to get some, you know, you get some of the branches, but you weren’t harvesting half and then half, you’re harvesting more like, a quarter and then a quarter. And you would, you’d be still missing some, which isn’t the worst thing. You call it, you know, animal fodder or something, and, and feel good, but it’s doable, I think, just from a production standpoint, it’s a lot more effort than just driving straight down a row and straight back down a row. But I do think with the right spacing of the trees, that’s where so we tried doing that with our, our smaller site, and those trees were just too close, closely spaced, that you couldn’t, you couldn’t get that weave effect quite the same way as our larger site where the trees were planted more in that, that 30 foot to 40 foot kind of spacing. And that that range really made it worth it. And we could get enough currants pulled in to make it I think profitable at that point. And then, but I think from you know, planting out standpoint, there’s, it’s kind of nice to be able to just run it right down and run it right back. Yeah, cuz you can you can haul on those things.
JASON FISCHBACH 36:30
Yeah. Okay, well, maybe let’s just shift to a little bit, we don’t need to go into too much detail because, but just sort of black currant culture 101. I got a field and I want to plat currants, you got five minutes to tell me how to do it. Go.
Eric Wolske 36:46
Cool. So what I would do is the first step is I would do site prep, getting rid of the weeds. weeds are, in my opinion, the worst competition you’re going to find for currant. If you have heavy perennial grasses, your currants will die. If you have a really, really bad thistle problem or something, your currants will probably die. They will not establish. They tend to get choked out really quickly and they are not competitive. They’re woodland species, woodland species do not compete with grassland species, grasses always beat forest. So that’d be my first thing. Control your weeds. If you have good controlled weeds move on to step two, which would be, in my opinion, your best bet is to take cuttings and put in direct cuttings. The second best option would be bare roots. And third option would then be to go and actually do full planted tree, you know, full full potted potted plants.
JASON FISCHBACH 37:46
Real quick on the planting stock. So you can what’s mainly available bare root and these tissue culture plants grown in plugs, is that how do you feel about those?
Eric Wolske 37:57
That I mean they work they tend to bring up the cost, which is unnecessary in my opinion. The currants just grow so well from cuttings you can, we fill on all our plants that don’t make it by just taking a cutting when we’re pruning and you just shove it in the ground and leave, you know, four to six inches above and for the most part that seemed to work remarkably well. I think from a from a smaller standpoint, it might be easier just to get plugs and plant plugs. And you can you already are assured that that plant is healthy and good to go in the ground. But from a cost standpoint, from a farming standpoint, it would be hard to justify such a high cost increase compared to just a bare root or even just a single cutting
JASON FISCHBACH 38:46
Are any of these newer varieties patented or are you afraid of propagating with the cuttings?
Eric Wolske 38:52
So ‘Blackcomb’ is one of the most, probably the most common one you’ll see. I think Adam McGinnis and that one is patented. Titania just came off patent. I’m actually not positive about the Ben series. And I think Tipin is a Polish variety that might have just come off patent, but I’m not positive on that.
JASON FISCHBACH 39:17
Okay, so just so our listeners are clear if they’re patented, you’re not allowed to, to propagate through cuttings even on your own farm, right? You certainly couldn’t sell them, but you can’t.
Eric Wolske 39:26
You can’t sell them. Sometimes what you can get through is depending on who the patent holder is and what rules they allow, you can sometimes just pay them the royalties. And so you say hey, I want to expand an extra five acres, and I’m going to be planting out you know, 10,000 cuttings, they say cool, send me over the check for, you know, X amount of money for plants, and we’ll call it good. So, selling outside of that though, they want to make sure that you’re not selling off bad genetics. And there’s been cases of like with Titania, all of a sudden now they’re finding that it might have white pine blister rust, and they believe that’s because of a nursery selling off stock, and not doing a good job of controlling genetics, and so that’s as much of anything the reasons why patent holders are very particular about their patents and who can buy them. It’s not always from a, you know, need to get the money standpoint. So as much protecting the genetics and saying, this is a good product, and it’s a safe product, and it matches everything you want.
JASON FISCHBACH 40:26
Okay, alright, so you got your plants that you’ve chosen, keep going.
Eric Wolske 40:31
And so then I would put them in the ground, the first thing I would do is weed control. So whether that’s a conventional method of put down some pre emergent options, that there’s plenty of pre emerge options that you can use for the first year for currant production. Or I think at this point, my biggest recommendation would be to put down some sort of fabric mulch. And you know, up there in Wisconsin, I would go with I think a black fabric mulch is just fine. DeWitt makes some really good products for that. Whereas I think down here in Central Illinois, we are, we are in the lowest Southern range for growing currants. And so they they have a really hard time with our heat, especially our 95 degrees in July during harvest heat that we get. And so in that case, I would go with more of a white mulch, probably, but I would put down a fabric mulch, that way, you don’t have to worry about weeds coming in there, really at all. A lot of those are also able to put in your fertilizer. So your first year, you put them in the ground, you control weeds, that’s your biggest issue. Then moving forward, what you’ll end up wanting to do, you can, you can go through and you can trim the tops to encourage shoot growth. I’ve, I’ve actually I actually think at this point, from a commercial standpoint, just let them grow. Don’t worry about topping them or anything like that, they tend bud out just fine from the basal area. Then from there, you go into year two, that’s when you want to start adding in your fertilizer. Currants are a heavy feeder, they are listed at needing 100 pounds of nitrogen per acre per year, which is a lot.
JASON FISCHBACH 42:08
Yeah, I read that in one of your publications. And I thought did I read that right? That is, but they respond huh?
Eric Wolske 42:15
Yeah, I think it’s as much because they’re shallow rooted plant compared to most of the fruit crops where you typically are restricting nitrogen. And we pull off so much biomass from them per year, especially once they hit maturity. And that’s a mature plant, you are at 100 pounds of nitrogen per acre, you would not put 100 pounds of nitrogen per acre on your two or three year plant. Those ones are more at the 20 to 40 kind of range essentially goes up by about 20 pounds per nitrogen per acre per growing season, essentially. And then maxes out at 100 pounds. But that’s something I would like to see a little more research on at least in the Midwest, because our soils are very rich compared to where they’re traditionally grown over in the UK or Scandinavia, where they have, they don’t quite have our deep, healthy loamy goodness of soils that we have here. Sure. And so that recommendation might fall down on more and more as we get a little better research into that. But as of right now, that’s been the recommendations I’ve gone with. And that’s what I that’s what I’ve been going with So, but maybe that would help control some of our powdery mildew issues or something a lot of times nitrogen can sometimes open up your plants to disease issues. So it’s something to look into further but yeah, putting down a heavy amount of nitrogen. You can do that with compost. Compost is not a bad option, currants like that cool soil and you put down compost and you have cool soil now. One of the major issues though is is voles. Voles love to bury in the root zone. They love to chew on the roots, and you put down mulch, you put down compost, and you’ve just gave them the best habitat for them to run around in and to thrive. And so that’s where it can get a little iffy. So most of our trials are done conventionally with herbicides, to control to control weeds.
JASON FISCHBACH 44:15
So put a cutting in the ground, let’s say this spring, when am I going to pick my first black currant?
Eric Wolske 44:22
So if you’re in Champaign, if you’re in Central Illinois, year three you can be arguably getting, you know worth going out there and harvesting. Getting up into Wisconsin, I would say year four and arguably maybe even to year five I think you might have a good idea of what the sort of the Northern limits look like there.
JASON FISCHBACH 44:42
Yeah, for sure by year four. Yeah, yeah. You know, if it’s a bare root plant a sizable root system for sure. Year four, most likely year three if it’s a cutting, you know, and it’s struggling that first year a little bit. I might push it back a little bit but yeah.
Eric Wolske 44:58
Okay. Yeah, and that seems to be yeur three. By year five, I think is when we would consider those to be mature plants. We’re going into year five now. And they’re, they look like a currant planting. They look, they look big, they look large, they look healthy.
JASON FISCHBACH 45:15
And how tall will they get where you are?
Eric Wolske 45:16
Yeah, so titanium right now is standing at maybe up to my nose. So maybe a little over five feet tall, five and a half. And the biggest issue I think, is what we’re having is a lot of the arms like to lay down so they they go up tall and they start to lean. And that’s as much I think, yeah.
JASON FISCHBACH 45:41
And then they rootif they hit the ground, right?
Eric Wolske 45:44
Yes. Yeah, some of them root like a blackberry does. I mean, they, they’re hovering above the soil, and then they’re like, well, it’s time to root out here.
JASON FISCHBACH 45:56
Okay, so the bane of all black currant growers pruning, how do you do it? What’s recommended?
Eric Wolske 46:02
Ah, at this point, I would, my back says coppice then my back says to go through we one of the farms had was using a BCS sickle bar mower to fairly good success. And just mowing them down, you mow them down in a capa cycle of usually three, although I, we have a little trial going on, I think there might be evidence for even pushing it to year four. And so you take out a quarter to 1/3 of your fields production every year, but you save yourself, maybe 90, you know, 80 90% of your time is saved. But if you do hand pruning, hand printing is not a horrible option. You prune them back to make sure that you don’t have too many overlapping stems you want good healthy one year, one year stems and shoots from it. And but you still want a good amount of the sort of the older wood because that older wood will throw off ideally some nice healthy one year shoots. And I will say that pruning for the blackcurrants is different than pruning for the other currant species, the ‘rubis’ species, those ones will also fruit on second year wood. And so that kind of changes up a little bit more of your style of your pruning methods. And you don’t tend to, you don’t tend to keep as many canes and you try to keep more single larger stems that then have a lot of that fruiting wood on there. And so it’s a little bit different between the two of them and red currants and white currants tend to throw a lot of low shoots out, that can be pretty quickly pruned. Whereas the black currants, the black currents, we tend to prune those out into more of an open base style style setting. And I guess.
JASON FISCHBACH 47:54
Not pruning black currants is not an option, right? I mean, they just get so overgrown that they.
Eric Wolske 48:01
I haven’t done it yet, I haven’t seen them, you know, I’ve seen a few that we’ve let go just for about the past five, six years, they’re still producing, and they are just incredibly dense. They’re these massive plants, they almost are competing with some of the hazelnuts in terms of in terms of like just density. So arguably, you might be able get away with missing a few years of pruning. And and still having a healthy plant, but they tend to have a lot of issues with that year four those those canes just start to die. They just they really just kind of give up. And I think it’s almost a self pruning by the plants. But from a from a farming standpoint, that’s that’s wasted space that you have now. And it’s taking up room. And so you kind of want to at the very least, a quick pruning just to remove all the old wood and kind of diseased sort of wood would be very, very worthwhile, I guess I’d add a couple more things would be plant spacing on black currents, you can grow them in a hedgerow system. So we grow them out at two foot spacing. And they grow in these real dense hedges. And which can be a real pain for hand harvesting, but works incredibly well for the machine harvesting. Whereas if you’re going more for a you-pick style operation, or even just you’re gonna be hand harvesting with them, then that’s when you want to kind of space them out into that four up to six foot range. And then you have these nice big open currant plants so you can get into and really, really get in there and and harvest from them easily. So that’s one thing and I guess one thing to add to the hedgerow system is that the Wersja, the company that makes the Joanna they do have shrub shapers, and so they make this thing that you kind of drive along and it keeps the plants in an upright position. And that’s what they do for pruning maintenance before coppicing is that they just let them go. And they just run that through for the first three or four years. And that keeps the shape up right without having to go out and hand prune those out. And then that’s the only prunting they do is running those through, and then they coppice them. And so that I just I just discovered that one recently, and that one has kind of opened up some dreams into a full commercial currant operation could really look like here in the U.S.
JASON FISCHBACH 50:33
So that’s taken off all those branches that are hanging down.
Eric Wolske 50:37
Currants just love to do that, especially with that fruiting wood. They’ll throw out those nice healthy one year and then they get covered in fruit, and then they’re just down on the ground. And you’re like, now you’re now you’re nothing except for rooting and causing headaches.
JASON FISCHBACH 50:52
Right. And do you see you know, with raspberries, sometimes you’ll put a single wire trellis on like a T trellis. Can you do that with currants and tie those canes up? Or is it just too much work for the volume of fruit that you are, or value of the fruit?
Eric Wolske 51:07
So my guess as to why you don’t see that is because they are marketed as machine harvested fruit and if you have wires in the way, you’re not gonna be able to machine harvest as well. And so I would I would say probably not, I would say you would have a better chance of seeing that then I, once again, I think that’s where the red and white currents are, I would view them at least for Illinois, and arguably for the Midwest as a trellised fruit. And they should be considered more of a trellis fruit. And putting out on a one two wire single wires. So more of like a low standing grape, kind of look instead of the T wires that you kind of more see with the.
JASON FISCHBACH 51:48
And I would echo that recommendation for for red currants as well. Don’t even bother as a shrub, the quality and the ease of picking on a trellis is so much better.
Eric Wolske 52:00
Yeah. And they look cleaner, they just look nice, just from a as a farmer who’s very big into aesthetics, I would, I would I would trellis them.
JASON FISCHBACH 52:10
As we get to the end here just to repeat, I know it’s still your results aren’t all in yet on the blackcurrant trials, but you have you know, the top three or four that have your eye terms of varieties to look at.
Eric Wolske 52:23
So the honestly the biggest downside of our trials is that we are using cultivars that are unavailable right now. Some of the McGinnis varieties that I am probably the most ecstatic about are still unavailable for sales, they’re still in the developmental stage, but hopefully, that will be changing in the next few years. So like and those unavailable ones the the ones that people should keep on their list of, you know, keep an eye out for in the coming future was the the ‘Chico moose’ or ‘Chaco moose’ cultivars. It’s a very high yielder the fruit quality is mild. And actually that’s probably the biggest complaint we’ve gotten from our taste testings is that this fruit just doesn’t doesn’t quite have a full flavor. It’s more of a watered down black currant flavor. But I almost argue that’s why we might be able to attract the Americans in.
JASON FISCHBACH 53:21
I’m thinking Hmm, that sounds kind of nice.
Eric Wolske 53:23
Yeah, exactly. And then that same vein is the ‘Nicola’ blackcurrant variety which is also a very high yielder and, and has a milder flavor. The best one I found so far that’s currently available is ‘Blackcomb’. I’ve been very impressed that one is the best looking plant, which once again as an aesthetic farmer, it grows the, grows the most even and upright, we don’t have to worry as much about the plants falling over the most disease resistant that we found and the fruit quality has actually been the most preferred overall. We actually sold a few 100 pounds to the local brewery in town here and they made a blackcurrant sour and they specifically wanted the ‘Blackcomb’ after I sat down and tasted, tasted through the currants with them. Some other kind of.
JASON FISCHBACH 54:20
‘Blackcomb’ is from McGinnis?
Eric Wolske 54:21
Yep. Want to say that I think tosses a couple of varieties are also available from them. And I would say like any McGinnis variety so far that we’ve tested have been very exciting to see they’re all very high yielders with very good fruit quality. But they have we have found that some of them have this newer disease that we’re discovering which is called cane die back, currant cane die back also known as Boctriferrous Ribus and some of them have been found to be incredibly susceptible to that. That’s been very concerning But for the for the most part, all the varieties that I just listed are all varieties that haven’t really seemed to have an issue with it yet, so.
JASON FISCHBACH 55:09
Okay, maybe finally, we should talk about powdery mildew because that’s one thing being up in northern Wisconsin, we just don’t have the heat and humidity. And I don’t think I’ve ever seen powdery mildew on our currants. So do you think it really is just a, I mean, obviously, there’s some disease resistance that we can play with, but it’s more of a climate type issue than anything. Yeah.
Eric Wolske 55:30
Mm hmm. Yeah. And so that’s why I think proper pruning and giving them proper, you know, it’s like the one of the major advantages of pruning is that you have that better airflow and better light penetration, keeping your plants healthy, and really making sure, we’ve had some issues with iron and magnesium chlorosis in the early springs, with those wet soils, and I think that tends to exasperate the powdery mildew problem, it really just kind of allows those plants to kind of open up so one of the farms around here is actually going to experiment with some micronutrient options to see if that might just they can just plant you know, boost the plant bigger will that reduce some of the issues they’re seeing with the cane die back and also with like a leaf spot on some of the red currants and then also powdery mildew on some of the some of the lesser varieties they have. But we have had we have found good success using a product called MilStop stop, which is a potassium bicarbonate. And also just with using mineral oil. The issue is that the mineral oil really becomes an issue when we have those hot summer days and we can’t spray because that will choke the plants out if you spray the horticultural mineral oil. And so we’ve that’s where the potassium bicarbonate has been really nice because we can spray that at any conditions. We’re not really as worried about it or as restricted. And those all seem to be doing a pretty good job I think of controlling the disease on the susceptible varieties. But in terms of cultivar selection, all the new cultivars for McGinnis are all resistant. Many of the newer releases out of Europe like ‘Tiben’ are all resistant as well. ‘Ben Lomond’, we have a horrible time with that. That one is that one is actually right now kind of our our diseased option, we can go out there and show you pretty much every disease we have on currants with that plant. It gets it gets the white pine blister rust real bad too. So we can use that as our as our show and tell for here’s why currants were banned. And so it’s kind of, as a research plant it’s been a really fun plan to have, but commercially, maybe not so much for down here.
JASON FISCHBACH 57:50
Right. So how about spotted winged drosophila?
Eric Wolske 57:57
Knock on wood have not seen them on the currants, we get them in the elderberries real bad. We know they’re here, we get them in the raspberries real bad, but we have not seen them in the currants. And I’m hopeful that the thicker skin that’s on those currents is enough to keep them out. I haven’t really checked too much on the red and white currants for them. But seemingly are also not a big deal yet. And I don’t know if maybe we’re just because we harvest those so early. Those are harvested mainly in in late June through early July. If we’re kind of narrowly missing that window when the spotted winged drosophila really is coming in strong. And so that might be sort of a lifecycle benefit that we have available to us with the currants. Yeah. But yeah, so far, so good. And I’m hoping it stays that way.
JASON FISCHBACH 58:46
And that’s been been our experience up here we see a little bit on the very tail end of like the later maturing, something like Blanca and if it may not even be Spotted Wing that’s in those, it could just be a whole range of drosophila that’s taking advantage of those overripe fruit you know, like I said, it’s the very tail end. So with the early ripening and thicker skin I think you’re right I think it’s resistant to Spotted Wing but it’s, you know, might be like a grape where it’s just not as big of a concern.
Eric Wolske 59:16
JASON FISCHBACH 59:17
As the other fruits.
Eric Wolske 59:18
I’d like to see that. Yeah.
JASON FISCHBACH 59:23
Any last thoughts about currants or suggestions or comments?
Eric Wolske 59:27
I would highly recommend to grow them. I think growing them in a full on farming commercial system is a great option. I think including them into a little agroforestry or even into like a food forest style thing. I think that’s a good option as well. They they are in my opinion, still one of my top recommended shade tolerant fruit crops. And I think a lot of lot of people could stand to at least go out and try a currant if you have the opportunity to and if you have the opportunity to take a cutting from someone I think go out there and do that and get some plants going and, and and start growing them wherever you can because I think they’re a great crop. I think they have huge potential for the health food market and just for overall taste, and we just the biggest the biggest hold back and setback we have right now is that nobody knows what a black currant is or red currant or white currant. So I think the more people that try them, I think we’re going to just see them keep growing. I don’t see any one all of a sudden being I don’t see the American market all of a sudden reverting back to nah we don’t want it, I think it’s going to be a an up and coming market, especially what I’ve been seeing with especially in like the brewing, wine, liquor world. It’s more and more products are throwing in black currants in particular, but also like the red currants I saw, with the red currant wheat. I think we’re only expanding into a realm of great opportunities and it’s never too late to throw out a couple of acres of blackcurrants.
JASON FISCHBACH 1:01:21
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