Shoots - Asparagus and Rhubarb
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EmailFebruary 26, 2025
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In this “spring-ahead” session, the Bens will snap in to the best ways to grow these two spring-harvested perennial vegetables.
Ben Werling is an MSU Extension vegetable educator serving commercial vegetable producers in west central and northwest Lower Michigan, the heart of asparagus land.
Ben Phillips is an MSU Extension vegetable specialist in southwest Michigan growing vegetables for research projects and giving advice to growers when desired. He likes listening to growers.
The 2025 MI Ag Ideas to Grow With conference was held virtually, February 24 - March 7, 2024. This two-week program encompassed many aspects of the agricultural industry and offered a full array of educational sessions for farmers and homeowners interested in food production and other agricultural endeavors. More information can be found at: https://www.canr.msu.edu/miagideas/
Video Transcript
Hey, good morning, everybody. We're going to get into some perennial vegetables today. But first, my name is Ben Phillips. I work with MSU Extension in Southwest Michigan and I've been working for MSU Extension for about 11 years. Ben Werling is my counterpart and he's been with extension for about 12 or 13 years now, Ben, is that right? 12 years still hoping for Lucky 13. All right. And he works in West Central Michigan in the heart of asparagus country, and we've asked Ben to talk about asparagus today and I'll be talking about Rhubarb. But first, I'd like to introduce our sponsor who's already put some information in the chat, Steve Kluemper from AgriStrategies, LLC. He's been a longtime sponsor of this program. I really appreciate the support, Steve. And through AgriStrategies, you can get some consultation on how to grow in more ways than one. Rhubarb. Rhubarb originates in the Himalayans, in the Tibetan plateaus and there's several species, like dozens of them and they all hybridize together. The actual species name of rhubarb is a mystery. We don't exactly know what its original plant is because it's a misshmash of stuff. But here's one in its native habitat. They call it the greenhouse plant because it makes these somewhat transparent leaves that allows light through but protects it from cold temperatures and it flowers completely inside that spike. Okay. What else can we learn about rhubarb before we get into the meat of production? Well, it's past its heyday, basically speaking, Rhubarb used to be very, very popular and it was a medicine in Asia, moved to Europe where it became less of a medicine and more of a cooking dish, but it was always the roots that were used. Eventually, the stocks were used, and they were almost ubiquitously paired with sweet things. In the 1920s and 30s, Michigan was the rhubarb capital of the world for forced rhubarb, which is rhubarb grown in dark conditions like this in the wintertime. But since it's passed its heyday, most Americans relate to rhubarb a bit like this. It's a plant that their grandma has, and it's a very generous plant, and grandma likes to give stuff away. You can take stalks, come cut some out, dig out a piece, take it home with you. It's an oddity. But it is still a culinary plant. It's very commonly paired with fruit, as I said, So because it's paired with a fruit all the time, it's actually considered a fruit for tax purposes. And this dates back to CJ Tower and Sons versus the United States in 1947. This importer in Buffalo, New York, wanted the Customs Department to tax rhubarb at 35% instead of 50%, like fruits instead of vegetables. And they won that case based off of a lot of personal testimony on how rhubarb is used. And also some precedent in, I think it was a 1918 case by the Supreme Court that decided that tomato is a vegetable, even though botanically speaking, it is a fruit. It comes from a flower, it has seeds, but it's cooked like a vegetable, and so therefore, it is a vegetable for tax purposes. And rhubarb is a fruit for tax purposes. Here are some examples of how rhubarb is used. It's almost always reduced to something that is added with sugar. Sometimes it's the raw juice. The juice is used in ciders or vinegars. It can move into alcohols. You can make jellies and pies out of them, of course, and then the original use of rhubarb. Is the root for medicinal use. But you can see in most of these cases, you're looking at sweet things and the rhubarb is added as a tart agent to change the flavor profile and the feel in the mouth. It's a fun thing. It's an adventurous thing to have sweetened tart together. So when it comes to selling it and marketing it, in a fresh market scene, it's almost always bunched. Sometimes you can box it up, but it's almost always bunched and they're usually working with about a pound and a bunch, which is about enough for one pie. There's also a processing market. I'm not aware of one here in Michigan, but they are sometimes individually quick frozen. And as you can see here in this pouch, that's actually referred to as a fruit, an individually quick frozen fruit, though it's a stalk of a vegetable plant. So what makes a good variety of rhubarb? If you want to get into growing it, you might want to start with some good varieties. I can tell you a little bit about where the market seems to be focused and some varieties that you might choose from. There's not a lot, but it basically comes down to the looks by the customer. Most people enjoy red over green as a mature stalk. They all start pink when they're coming out of the ground. And if you were to force them in a dark room or under a under a bucket or something like that, they are even more vivid pink. But in general, they start pink and then they either go red or green. Most people enjoy red and maybe it is an eye thing, it could be a flavor thing. It seems through literature review that the reds have less acid components to them. Even if they are less sweet than a green in some cases, they may be perceived as sweeter because they have less acid. Sweetness overall is very low, even for the sweetest, it's about six brix and that's pretty low on the brix scale. Another factor for how well people enjoy rhubarb and what makes a good variety is how well they maintain their stock integrity. They can be really pithy and stringy in the heat. If you have a variety that can maintain a nice crisp, snappy stem into the summer months, that might serve you well depending on your market that is. But all varieties usually snap pretty well in the spring. Then the last thing that really makes a good variety is how much it doesn't flower. A good variety doesn't flower. You want a variety that doesn't flower or not very much, that is, and that is because every time it flowers, it diverts a lot of energy to making seeds instead of fueling its root. If you have a variety that does flower a lot, you have to go out and cut those. I wanted to share this picture here that shows how the color inside the stem is also variable. You can have some varieties that are red only on the surface and some that are red more in the middle, and some that are green in the middle, even though they're red on the outside. When you go through catalogs, let me see. Let me get to the next slide. When you go through catalogs and you look at different varieties, there are names. There are names, but due to how complicated the breeding past is in rhubarb, the names are not usually very trustworthy. Like I said before, they hybridize really readily and a lot of people traded rhubarb and they traded rhubarb without necessarily knowing the history of what it was. And after long enough, if people started dividing that and spreading it and dividing it and spreading it, they made new names for it, even though it may have been the same variety. It's hard to explain, but it gets really complicated. That means when you get these varieties, sometimes you get a lot of variable performance in that they'll have variable color in the stalk or the internal color will be really variable. It might have been marketed as a low flowering variety, but sure enough, a bunch of them are flowering. It's very common in rhubarb to get not quite what you thought you were going to get. But in this list is basically the short list of what you can get in the United States. In Europe and in England, there's like 60 plus varieties. But over here, we only get about ten and of those four are pretty readily available. Canada red is a really high performing red variety, and it doesn't flower very much. It's got a lot going for it. Crimson red is another popular red one that is really easy to get in high quantities here, but it flowers a lot. So if you want to be snapping flower stalks all the time, I guess that one's for you. In the greens, Victoria is by far the most common. It's not straight green. It's like a variable green. It's speckled with red, but it's a variety that is probably the leading variety around the world. It's the easiest to get by far in high quantities. But it's also a high flowering variety too. Despite how popular it is, it does flower a lot and that does require some pruning to keep a high production going. The newest varieties here are Hardy Tarty, KangaRu and Starkrimson. Those are actually trademarked through gurneys and Stark Brothers. I don't have experience with them, but they're really the newest ones on the block, and what they all have in common in their marketing materials is that they are heat resistant, and some of them are a little shorter. So that might be something to consider if you're interested in trying to extend rhubarb market into the summer months. So you can get them by roots or by seeds, and it's most commonly sold by the root clone. It's a chunk of root with a bud on it, and then that's where the plant comes out of. It's usually harvested in the fall, so when you get them, you get them and they're in a dry form. You can also get them by seeds, but that's not typically recommended because you get a lot of genetic variation that way and an inconsistent crop. It also takes about one to two years longer to reach a harvestable stage by starting from seeds. This is a fertilizer plan that you could consider for rhubarb. It's on the low side. I've seen some other recommendations that show far higher fertility needs, but also some research out of England where they grow a lot more rhubarb than we do, showing that they don't respond to much high rates of nitrogen in particular. 50 pounds per acre is good enough. You can get up to 170 or more pounds per acre of nitrogen for rhubarb and not really see any difference in the way that they produce. I'm sticking on the low end here. And given that they're a fairly niche crop, I wouldn't spend a ton of money on them and they're very robust. They they do all right. Basically, you start with 50 pounds of nitrogen per plant in any of your P and K. You can add more P at plant to get them going. Then each spring, once plants are started, you can add 50 pounds of nitrogen in the beginning of the season to get them going before the growth really starts. Then after final harvest or near the end of the season, give them another shot to a total of about 80. 30 in the fall, 50 in the spring to make sure that they have a nice set of buds going into the winter. Then with some soil testing, you can decide if you might need to re up on potassium. So how do you plant it? First off, don't plant them in a wet spot, number one. Number two, you can use a small trencher, not very deep. You don't want them too deep. Later, you'll learn asparagus is deeper, but for these, they only want to be one or 2 " underground. But a trencher can work to make a long row that you plop your roots into. You want to throw them in so that the dormant bud is up if possible. And then they'll grow from there. You can then fill in around those plants with compost or manure or soil. How much to plant? That's a good question. I'm going to open up this little worksheet that I built for you all, and I'm going to put the link in the chat. I'm not going to spend a lot of time on this, but you can use this worksheet by filling in the orange cells to figure out how much you need to plant for a given market. If you use this, I would ask that you make a copy for yourself before you start changing the values around. I'm going to put this in the chat You could use this for both rhubarb or asparagus. Once you've got your rhubarb planted, how you harvest it? It's a perennial and you want it to be building a root so that it maintains health over time. In the first year, you don't pick it, you just let it grow. This is my PowerPoint rhubarb field here. The first year I just let them grow and be happy. After that, year two, You can go one of two ways depending on what your scale is or how you market. The first way is to do a selective pick, which is where you walk through the patch and you pick the stalks that you see on the plant that are marketable and you cut those and you package them right there. This is like the Ben Hartman lean farm way to do it. Only pick the good ones and put them in the packaging right there so that you only touch it once. And then every time you go out, you just selectively pick different parts of the plant. You're never ever taking everything off. You're just picking sections of it. The other way to do it is through sequential picks where you actually remove all stocks from the plant at one time and you don't remove it from the entire planting. You do some plants or sections or rows until you hit everything and everything's down to the ground. You can do that usually once per plant, maybe twice. The way that you would harvest it and pull it is you just do a twist and pull and it comes right up from the base. This is an image showing someone doing that and he's got rubber bands on his hand. He's doing the selective pick style. He is picking stocks that look marketable right there in the field, gathering them and rubber banding them right there. This other method here is also what looks like a selective pick to me over on the right hand side. They're picking stocks and they're putting it on a harvest aid, a conveyor that brings it to a central cart where they get packaged there. This is a much larger scale situation. That would be something that you would do for about five years. You're picking these plants for about five years, maybe up to eight years depending on your mood and how well the plants are doing. They can eventually get a little crowded and they start making spindly stalks. Oh, Ben asked, is there a time to stop clear cutting your rhubarb? Yeah. Usually, it's very similar to strawberries and asparagus. You want to quit around the end of June, early July. You could go into July a little bit. But if you have a variety that's not great in the heat, that makes the decision for you. Yeah. So after a few years of that, you might want to split the plants so that you can reduce the crowding in the field. To do that, you got to dig them up and you actually have to cleave them apart with either a nice sharp shovel like this or an axe. I've seen axes used as well. The fields it's like plowed so that the roots are just shoved out of the ground, and then you go through and you start busting them up for a new planting. Let's talk about some of the production limiters of rhubarb here. We've got weeds, that's a real big one. Weeds in a perennial crop tend to be perennial themselves. They can be a real hassle. In this field here, I see what looks like some wild lettuce, maybe some mustards. We got a mixture of perennials and annuals in this field. One of the key tactics in a perennial system is to prevent weeds from germinating to prevent planting in a field of perennial weeds. If you've got a field that's already got a thistle problem or a bind weed problem, it's not a great candidate for putting in some rhubarb. But there are some tools and approaches to handle it. There are some herbicide options. There's some spring burn down options where before the buds have started to emerge, you can spray the field with roundup or 24d or aim to try to burn down any vegetation that's there. Once the rhubarb is up, you've got some options. Oh, sorry. Before rhubarb is up and you want to do a pre emergent herbicide to stop annual weeds from germinating, there's a host of options. Um, Starting with Casoron and this part of the list going down to command, you could use several different products for that window. After rhubarb is up, your product selection goes down. There's only one product you can spray over top of rhubarb for the control of other broadleaf weeds, that would be Quinstar, which can help with some of the perennials like thistles and bindweed. For emerged grasses, there's three different herbicides that work on grasses that you can put over the top of rhubarb. Then Before fall cleanup, there's another window of time. If you do the pick method where you clear cut and you basically create a new clean field with no emerged rhubarb, you can also then do dual magnum again. Then in the fall, you can do round up again, just basically like the spring, you can do a broad spectrum cleanup once the plants are dormant again, and there's another herbicide that's only labeled for the fall called Kerb. So if spraying is not your thing, there are mechanical ways to do it. Yeah. We had a question in the chat. A two questions. One you're going to get to right now, I think. The first one though, is from Virginia who asks if you can use surf Land as a spring turn down. I don't know. Ben, you want to look up the label for SurfLand and let us know in the chat? Okay. I will try and find out. Thanks. So if spraying is not your thing, then you've got mechanical options and you have to think of like If you grow pumpkins or potatoes, how do you manage soils and weeds in those situations? It's very similar. They're widely spaced plants because they're very large. So you can fit tractors between rows in some cases, or you can straddle rows. And there's a variety of tools you can use to throw soil onto the plants in the fall as they're going dormant and then drag that soil off in the spring, much like healing potatoes. You can use eco weeders like this down here to get between the plants in a row if you've got somebody who can ride behind you there. If your field is big enough, then that might be a fun way to do it. But rhubarb a lot of folks don't grow a huge amount of rhubarb and so I would not consider investing in something like this just because you're putting in a small planting of rhubarb. But if you've got other crops that are widely spaced like pumpkins, then go for it. Other ways to go are mulches. For example, Ben Hartman here in his YouTube video about rhubarb has got landscape cloth, works great. I've also seen straw and wood chips. I think that when you use wood chips, you can get some nitrogen tie up over time, but as long as you keep those plants fertilized at their bases, you're all right. Chris asked, why not plant a dwarf Dutch clover as a permanent living mulch? I don't know. You can try it if you want. It's a perennial and perennials are the biggest weeds in rhubarb. If you want to deal with that, that's fine. I don't know. You can get some escapes in dwarf perennial. If you put a living mulch in, let me frame it to you this way. It would be much like using wood chips, okay? Once you've got something in there that you want to be permanent, but it's alive and you've got escapes in and amongst it that are not dwarf Dutch clover, I guess you're just limited to hand pulling at that point. And if you're all right with that, I'm all right with that. But if you've got a larger planting, I would just recommend keeping it clean. With diseases, that's the main production limiter outside of weeds. Number two, diseases. There's really only two issues. You can get some leaf spots. The plants tend to come through it. My recommendation is to start with disease free inspected nursery stock. So don't buy rhubarb off of Etsy? Then remove and destroy your infected stocks as you come across them. Wilts are another problem you get in rhubarb and it's almost always because of poor site location. Poor drainage, low spot, heavy soil, too wet. There's no way you're going to get out of that. The plants will just not work for you. You can't spray out of it. There's nothing you can do. It's all about siting. But if you've got some issues that you want to handle, also, keep in mind, the marketable part of the plant isn't the leaf, it's the stalk. The leaves can look crummy, but if the stalks look okay, you're good to go. But if you feel like you need some protectants to stop something or you've got a really long run of cloudy, wet, annoying weather, there are very broadly labeled protectins you can also use on rhubarb, including Bravo or badge, which is copper. That should have an asterisk too. Many of the coppers are organic. I don't know about Badge specifically, but I know coside O is a copper that's organically certified. Also, we've got some biologicals like trilogy and regalia. All right. Then insects. I wouldn't really worry about them. Sometimes you get some insects that blow up, but the rhubarb is a very hardy plant, very sturdy, and it's usually not going to impact the quality of the stalks. One of the primary pests that will get your attention quickly is a beetle called the rhubarb weevil. It's huge. It's one of the biggest insect pests I've ever seen. And so it looks big and scary. Its main food is curly dock, which is this picture here with the brown seed pods. It's a closely related relative to rhubarb and buckwheat. They're all in the same plant family. That's their main thing. They like that crop right there. They like the curly dock. And if you've got a lot of curly dock, then they may migrate into your rhubarb. And if that bugs you, then managing the curly dock is the primary way of managing that pest. All right. Ben, we're going to move on to asparagus now. Are you ready? I'm ready. If you are, Ben, if you could tell me if there's something in the chat, I would appreciate it. Please stop me. Sure thing. Okay. Okay. All right, everybody. So, like many of the crops that we farm today, asparagus originated in the Eastern Mediterranean. And then the Romans had an empire, and they liked it, and they spread it everywhere. It's one of a few closely related asparagus species that have separate male and female plants. The boy there's boy plants that make pollen, girls that make berries. It's probably a strategy that basically helped prevent inbreeding, helped it if you cross yourself, you might end up with problems. Um, Okay. Um, here in the US, there's a long history of asparagus production in some key states including California, which used to be by far the biggest dog on the block, Washington, which was right up there, New Jersey and Michigan. A lot has changed even in the last 12 years since I started, California has dwindled away to basically nothing. Washington has reduced its acreage. Michigan is now the number one state because of that. And the reason is that in Mexico and Peru, they can grow it year round. And we can import it and they have lower labor costs. All that said, Michigan is still the number one state in the country, so it's a matter of pride. There's a June asparagus Festival in Hart with a parade and tasting, if you're curious. Um, it's one of those spring fever vegetables. The Germans have a word called Sparglzit asparagus time, which I kind of like it's festive. In heart, early in the season, when everyone's guessing when it'll happen, everyone guesses May 10th as the start date for harvest. And then basically that we'll have, um pickings basically every day unless it's cold up through maybe the third week of June for a six week season. Our growers can get up to 40 picks throughout the whole season. It's a busy crop, but one that people love in the spring. If you've gone to Meijer, you may have noticed that at times they have both green and white asparagus. What's the deal with white? Well, it ends up it's actually just a cultural thing. What is white asparagus? Just like Ben mentioned that the stalks of rhubarb turn red when they get above ground. It's the reverse. Well, I'm sorry. The stalks of asparagus turn green when they get above ground. If you want it white, what you do is you plant it and then build up these hills or ridges. Um, like you see in this left hand picture, and then they'll basically stab it underground and they'll get an all white spear. I mentioned it's a cultural thing. So in the English colonies in the UK, as well as Southern Europe, they eat a lot more green asparagus, whereas in Germany and the Netherlands, they like their white asparagus slathered in Hollandaise sauce with some ham. What makes a good asparagus variety? First of all, most modern varieties are all male, with the exception of an heirloom one. The reason for that is just like Ben said that rhubarb expends energy to make that flower stock, if you've got a female plant, it's spending energy on berries, not on recharging the root system. Tip quality. That's the number one quality trait that our commercial growers are looking for. And here's a grading sheet from asparagus. It's a picture of a picture. On the far left, you can see a nice tight tip where those leaf bracks have not spread apart. And as you go further to right to the right, you see something we don't want. And so some varieties are more likely to get, like, get open tips when it's hot and some hold their tips better. Diameter. There's a fallacy that comes from the gourmet magazines that skinny asparagus is more tender. Actually, if you think of a cross section of an asparagus spear is a circle, all the fibers in the outside. If you shrink down the center goodness, you're getting a lot more of that fibery outside and less of the internal goodness. Actually diameter spears are More tender, less likely to be overcooked. Longevity. We used to grow a lot of a variety called Jersey Giant, but it would only last eight years, especially on ground that had asparagus before that had built up disease. And that's why we moved to more tolerant variety called millennium, which can last 15 plus years. Color, I'll get into that in a second. But we have mostly green varieties, but we do have purple ones. The white asparagus isn't a separate variety. It's just a cultural practice. Okay. Hey, Ben, you had a question in the chat about you remove female asparagus plants? Oh, that's a good question. If you have a variety that has a mix, no, you wouldn't need to remove them. What you do then have to deal with those little berries will drop and they'll form little baby asparagus. If you have herbicide, it's not a hard thing to deal with. If you're not comfortable using it, you can get a carpet. Um, but no, those female plants will be productive. But what our modern asparagus breeders have done, it's really cool. They came up with a breeding process so that almost 99.9% of the seed that you plant in these all male hybrids are boy plants, so you don't have to worry about that. Um. One, the most commonly grown variety in Michigan is millennium, and By far and wide, it's the most widely adaptable, commonly grown variety. It can do well on well drained soils, and it can even handle a little bit heavier soils than some of our older varieties. It's easy to find online as crowns or as seed. There are some other varieties that may have some slight advantages in terms of tip quality, but me is hard to beat. The one heirloom we have that will produce boy and girl plants is Mary Washington. Um, Yields are about half of that of millennium, but if you like an heirloom variety, it's commonly available. Then purple varieties are interesting. They're definitely eye catching. They have a higher sugar content, so to the connoisseur, they are sweeter, but they yield less. But I've worked with a grower once who did some direct sales. Even though it didn't grow as well, the stores he delivered to love it, it is a neat. Okay. In terms of fertility, asparagus likes a higher pH than most of our veggie crops. A target is about six, eight, and one really important thing that you want to do before you plant it is make big pH adjustments. I'm going to plant some asparagus next year, but I waited because I know my lawn pH where I'm going to make a garden is five. And so this year, I'm going to work in some lime. The thing is you need to work in that lime with tillage through the soil profile. After the planting year, it's no till, so you don't have that opportunity. For a new planting, you'd want to provide some nitrogen and potash, work it in before you make a furrow, apply some phosphorus in the furrow, basically as a starter fertilizer. Then after the baby plants are up, some more nitrogen. Asparagus is not a heavy nitrogen user, it's just like rhubarb. What our growers will do is typically make a split application of half the nitrogen and recommended potash before harvest and half after the last harvest. Ben talked about sourcing plants. You can buy asparagus seed, and that is a relatively low cost way, at least in terms of getting plants. But what we've learned by trial and error in Michigan is that you'll get a really reduced stand establishment. You'll have big gaps, maybe three, four, five feet in your row that die and then never come back. Transplants are a much more reliable way to do it. They do have some reduced cost because you're not paying for someone to grow the crowns for you, and you can get it done faster. And because you're not taking a crown out of the ground and damaging it, there's a reduced risk of soil diseases. The big con to that is they take more intensive management. You have to have irrigation and do a lot of hoeing. The other thing is that if you've got a planted on the hillside, those baby plants, if a rain comes will get washed the plugs will get washed out of that furrow or buried. So crowns are what our commercial growers plant and most folks plant, and pretty much every crown comes up. The downsides are higher cost because you're basically paying for someone to grow a seed into a crown. You have more limited selection of varieties that are available, and because someone else is growing them for you, you may get their problems. This is a 1-year-old asparagus crown and it's neat. It's a complete plant. It's got an underground stem called lorisome and just like any plant on its stem, it's got buds. Those buds will send up shoots. They'll turn green once they're above ground and we'll either pick them or let them develop into a mature plant to recharge sugars into these storage roots. So this is the one asparagus planting I've ever helped out with, and I was happy that it came up. It's a nice way to illustrate planting. Okay, good question, Steve. Steve asked, can you explain more on transplants versus crowds? Do I dig and transplant from an existing row? The short answer to that is no. And I should have had a picture here. So let me start out by saying what a transplant is. So if you guys have ever bought a veggie transplant, think of something like a tomato transplant you buy at Home Depot. When I use the word transplant, that's what I'm talking about, where you take a a tray, you fill the plugs with media and you plant an asparagus seed in there and you grow it for 12 weeks. Then you take those plugs and then put them into the field. Hopefully that makes sense. When I use the word crown, what is happening is someone who's usually a specialized crown grower plants the seed in a field instead of a greenhouse, and then in the spring, they will go and dig those out just like you dig potatoes, and then you will buy the root. Some people will try oh, go ahead Ben, Oh, I was just going to say if you buy asparagus crowns from a greenhouse or a store or whatever, those were all contract grown. Well, somebody grows that, that's like their main deal, like Ben said, they're specialized to grow seeds in the ground and then they dig up the roots, and then those roots are wholesale sold to places like Gurney's and various other places that will mail order you crowns. Thank you, Ben. Some folks will try and do like you do with rhubarb and divide a plant. But the plants are huge. I had a picture somewhere, but basically you injure them and asparagus gets this disease from the soil called fusarium. If you do that, it's going to die. Maybe not right away, but eventually. So start with fresh stuff. So our growers will plant them on a four to five foot row spacing, and you can riff on that. This is just based on the common equipment widths that growers have. In Quebec, they'll actually do something different. They'll have two rows ten feet apart because it allows for equipment to go between them and cultivate and things like that. So you can show your target plant population in a second. You can get to that in different ways. Um, Furrows are six to 10 " deep. If you've got clay soil, you would want to be on the lower end, more like 6 ". If you're on sand, which most of our growers are, you'd be more like eight to ten. A middle buster plow is a tool that is accessible to smaller growers that you could use to dig a furrow like this. A target population is about 14 to 15,000 plants per acre. You can take your row spacing and then figure out what in row spacing you need to get there. Typically, it's about eight to 12 inches between plants or between crowns. Okay. Planting, you can cover the crowns with about 3 inches of soil. That's enough to get soil and moisture on them, but there's not a lot of dirt for that little shoot to push up through. About six weeks later, you can come back and fill the furrows about two thirds full. Okay. Got it. And so basically what you're doing is you're limiting the amount of soil that plant has to move through to get up and over. The year after planting, our growers will use a disk, but you could easily use a rake to level out to do one last leveling of the field. And then asparagus is no till the rest of its life, typically. Now, if you're an organic grower and maybe you went to that ten foot row spacing with double rows, you might do some shallow cultivation. You would have more room to do it. There's a trade off, but if that's your way of managing weeds, that may be something to consider. Okay. Once that bud comes up the shoot comes up out of the ground and turns green in May, it turns into a spear, which is what we harvest. After the end of harvest, we don't pick anymore, we let the shoots develop into a mature plant, which we call fern. Um, What you want to do after planting is gradually increase the length of your harvest period. In the planting year, you won't harvest at all. The year after planting, no picking. Two, you might pick it for two weeks, ramping up to six weeks in years four and five. Basically, you're letting that giving it more time to grow early on and develop the root system, and a mature planting can last for 15 plus years. How do we harvest? It's all by hand. If you look at the upper right picture, that is a Michigan asparagus harvesting crew. They snap spears by hand at about ten to 12 inches, and then they put them in these lugs and you notice the tips are all facing the same way. You can see that there. That just makes it easier when you're making bundles, you can just grab them and it's all ready just to put a rubber band around basically. The rest of the world cuts actually. This is a picture of a gentleman in Peru harvesting. He has a long knife and they cut it a little bit underground and grab the spear. In Michigan with our five man carts, you need about one person per four acres. Holy, that'll be more people if you're walking. Okay. Now we'll talk about production limiters, insects, weeds, and diseases. Just to lay that out, here's a typical asparagus season. If you're using herbicides, before harvest, you would apply a shot, let the spears come up and during your harvest season picking every day. You might need to control some asparagus beetle. After the last harvest, Apply another shot of herbicide, and then the fern season is when we do most of our disease and insect management because that's when the fern is collecting sugars to power next year's harvest. Then the plants will go dormant in October, November. So in terms of weed control, our growers will typically apply a cocktail. Roundup is used to burn down small emerged weeds, and they'll also include pre emergent herbicides to hold back emergence of annual weeds during harvest. The first thing to say is that roundup is safe to use before the spears are up and then after a last clean picking. A lot of people get worried about it, but it is safe to use. Um, Then these pre emergent herbicides can really help you out if you're comfortable using them. We have our April shot about two weeks before harvest. At the last harvest, our growers will either take a clean picking, basically clear cut the field like that rhubarb or mow it to about 10 inches to leave some weed surface area, but get rid of the spears and then apply herbicide. Ben, do you see the question there? I did. Okay. Steve asked if you can use shallow tillage in April for weeds. I think so. I"ll say a couple of things. One is that there's trade offs to everything. So the reason that our asparagus growers have gone no till is because tillage can damage the root system and lead to soil erosion. And basically, if you're in a annually tilled system, you'll get less yields. That's one of the trade offs of tillage, but shallow tillage could be a nice tool, especially for organic growers. I'll talk about diseases in a second. If you can bury that residue just a little bit, you can reduce disease pressure. Yes, maybe the planting won't last 15 years. But if you're in an organic system, maybe it's worth it to get that weed control. The other thing is that if you have a healthy planting and that fern comes up, there's really only about three weeks between the last harvest and fern closure, and it closes between that row when weed control is critical. Alexis, I will get, I've got a slide on your question at the end because that's a common question. Ben, I like that graphic. Oh, thank you, Ben. I guess I'll just add from the rhubarb perspective that the clean cut version looks almost exactly like this if you look at it linear or like that. But if you do a sequential pick, you could be picking rhubarb clear into August if you had a heat tolerant variety. That's really cool. As long as you leave some of the plant remaining to bring the sugars in. That's interesting. There's a system called the mother fern system that they use in tropical countries where you let some ferns develop and then you. They nurse the plant and it's interesting. This is if you can use herbicides, you have a really short window. In April, it's kind of rainy. And then after harvest, it only takes a few days before spears will come up after that last mow. So it's really easy to miss the window. and Santa Claus only herbicide is ho ho, so that's why this guy is there. This is just a picture of all the herbicides that are available. There's a lot of them. There's only a few labeled for new plantings. There's a lot more that are labeled either for before or after harvest. I also showed the pre harvest interval, and then some notes on what the herbicides are good for. Um. This is more of a reference slide for you guys. Up here, there's a couple of standard mixes that I confident are safe. Um, Prowl plus Tricor and roundup, or Spartan plus dual and roundup are pretty safe, and they're really nice mixes. Oops. Insect management. So asparagus beetle is a handsome beetle, but it lays eggs on asparagus during harvest, and our growers will manage them with one day to harvest insecticides, such as the one shown here. There is an organic option called Pyganic. Interestingly enough, it doesn't actually kill the beetles. It just makes it stinky, so they lay less eggs. But that is an organic option. It won't eliminate the problem. I wanted to mention that residue management again. If you can, the beetles will actually overwinter in old stocks. So managing residue is a way if you're small enough that you can manage these things organically, and you could do that by burying it or by removing it or burning it. Okay. During the fern season, you have asparagus and Japanese beetle. You actually see the grubs of asparagus beetle, which can defoliate the fern. These are the standard mixes for conventional growers. Spinosad is an organic option. It just kills the babies, though, it doesn't kill the adults. But it could help. Diseases. This is the main thing that growers focus on managing in the fern. We have purple spot and rust, and they will apply fungicides, such as these every ten to 14 days or with a weather forecaster. But if you look at this brown fern here, obviously that's not good. But if we looked closer, we would see overwintering structures of the disease, and that's what re-inflects the planting next year. If you're small enough, what you could do is once the fern is dead in November or in the following spring, you could remove that dead residue, and that may help manage disease. If you're going to spray the fern, it's about six foot tall. You either have to run over a row with a tractor and then lift your boom above it over the adjacent rows or use a high clearance sprayer or hire a drone or plane. Okay. Alexis, this was your question. I think a lot of folks have grown raspberries or maybe blueberries or tree fruit where pruning is a strategic thing that has to be done carefully. The only thing you need to know about chopping asparagus stocks is don't do it too early. You want to let the fern turn brown because it's sending nutrients back down to the crown. Typically, that's deer season here in Michigan, growers will mow shooting alleys in their plantings and have a deer stand at the end. Um, But in terms of when to chop it, you can do it in November or you can do it in spring. Either is fine. So what our growers have moved to is chopping in the fall. If you think of it as a shave, By springtime, the fern latches and it's harder to cut. But in fall, it's still standing straight so you can get a cleaner shave. Hey, Ben, there's a couple of questions that came through the chat publicly and privately about soil. One was about when you're chopping the fern like this, does any amount of tillage help to incorporate nutrient cycling? And then the other question was about, would light tillage help destroy asparagus beetles in the spring? Yeah. So, um First question was incorporating soil amendments. If you're using synthetic I don't think it was about soil amendments unless you saw a different question. It was more about burying the residue. And you've got chop residue all around it. Got it. So in terms of nutrient cycling, maybe they're talking about from the dead fern. Yeah. It's amazing how rapidly it degrades, even just sitting on the surface. That would not be a reason I would till or do shallow tillage. Um. In terms of asparagus beetle, I think this is just anecdotal, but there was a grower with a bad population who did move to doing some really light tillage and he felt like it helped because the beetles will overwinter in the stalks. That could potentially help. Another thing you can do is This is really only doable if you have 20 foot of row, but you could chop it and remove it by hand. There's even one grower who actually took a hay baler and bailed the dead fern. So that's the way to remove the fern without disturbing the soil. Another thing you could think about for weeds, I've never seen it done, but if you applied a straw mulch, I can imagine that you'd have to renew it kind of annually, but that could be a way to control weeds if it was thick enough. Then hopefully the spears would come up through it and you could pick them. Ben, do you see this question about healing asparagus? Steve, I think I'd be curious to know how it's fairing. If it's working, then that's great. In fact, in Britain, that's what they do. They re-ridge it every year because they have drainage issues, which sounds like exactly what you're doing. Um And there's nothing the tillage thing, I don't want to be dogmatic. What they have found in Britain is that they do take a yield hit by doing that, but you only need as much as you need, and you need a growing system that works for you. And it sounds like a really creative one. Cool. Other thing that's interesting is that you can use subsurface drip irrigation with asparagus and that could be a way to provide nutrient and fertilizer and water a little bit deeper where the asparagus is and keep it away from a ground cover or weeds. Thank you, Ben, for coming and talking about asparagus today. I hope you all learned something about rhubarb as well.