Hello seed friends. I teach a seed saving class in my community. Today we had a good question….What to do about club root on brassicas when you grow in a small space and over 50% of what you grow is brassicaceae. This fungus lasts fo 10 years in the soil making crop rotation in a small plot impossible. Has anyone breed club root resistant varieties? Are there microbes that help combat the severity of affected plants? What do you breeders say about breeding for club root resistance?
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Gosh, I know nothing about that fungus, and I’m interested to see what everyone else says.
My initial thoughts, based on no research, are:
- Are there any fungal species that can outcompete club root? If so, are any of them actively beneficial to brassicas?
- Are there any fungal or bacterial species that like to eat club root that would not harm your brassicas?
- If you planted things that are naturally antifungal (for instance, garlic or onions) all around each brassica, might that help deter the fungus, or at least slow it down?
- Elm oyster mushroom (Hypsizygus ulmarius) is said to be beneficial to brassicas.
- Wine cap / garden giant mushroom (Stropharia rugosoannulata) is supposed to be beneficial to basically all plants.
On a broader scale, here are my thoughts.
I think you may be seeing a common result of growing too few plant families in one area. Highly diverse polycultures in general are usually the best prevention (and solution) for problems like this. If 50% of everything you grow is in the Brassiceae family, maybe it would be a good idea to start seeking out other tasty plants in different plant families.
I’ve read somewhere that if there are members of at least eight different plant families in the same square meter, all the plants in that area seem to be way more able to handle stress. Even if that doesn’t happen, it would probably confuse and slow down the predatory fungus somewhat.
50% of what you grow can still be brassicas; just try having everything else be highly diverse, from a bunch of different families. Maybe try separating each brassica into its own little island, surrounded by loads of everything else, which may help weaken the club foot fungus’s ability to thrive a little.
If a lot of what you grow is brassicas, my suspicion is you’re looking for crops that can grow through the winter, so here are a few ideas you may try. All of the things I’m suggesting below are good winter crops for me. One species (or more) from each of these plant families may be helpful to you:
Allium family: Garlic, onions, leeks.
Legume family: Peas, fava beans, garbanzo beans.
Honeysuckle family: Mache, Jupiter’s beard, honeyberries.
Grass family: Winter wheat, winter barley, winter oats.
Carrot family: Carrot, skirret, lovage. (Those three all grow actively during the summer, but their roots are still alive in the soil during the winter, so that counts.)
Nightshade family: Potatoes. (Same idea.)
Aster family: Dandelion, lettuce, sunchoke. (Same idea with the last one. Sunchokes are said to be a little bit alleopathic, but they don’t seem to bother the brassicas or legumes I grow right next to them at all.)
Asparagus family: Asparagus, yucca, brodiaea.
Mallow family: Common mallow, high mallow, hollyhocks.
Mint family: Apple mint, chocolate mint, sage, lavender, anything evergreen in the family – just be aware that most things in this family can spread and get weedy.
Lily family: Tulip, tiger lily, day lily.
Violet family: Violet.
Everything I’ve listed above is edible, and there are a lot of different sizes and growth habits and crop types represented. Getting a mix of lots of variety will usually do the most good and create the least amount of competition for resources. If you’re interested in summer crops too, there are tons more options. Do any of those give you good ideas?
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Thank you for your thoughts and time!!! i especially like the initial thoughts and will look into other bacterial and fungal relationships great idea!! Im sure the large diversity helps, thats a great point and love your plant list however I’ve lived on the bullocks permaculture homestead for 6 years and we plant the way you described very large diversity of plant crops (ive actually grown everything you mentioned except my skirted hasn’t been successful yet) from a large diversity of families, and even there we were dealing with this club root (thought easier to deal with than on the smaller scale i first mentioned)… i think the hardest part is this particular fungus stays in the soil up to ten years … perhaps even more separation with the little brassica islands rather that a couple brassicas together surrounded by other crops would be more beneficial, ill try and report back… I did notice i had regularly good brassicas near my long line of chives in the garden, so the allium idea is a good one.. I guess i get to go down a fungal and bacterial rabbit hole now!! I got the book breeding for resistance and im hoping that will give me some ideas too. For example the red Russian kale is almost never affected, I know it’s brassica napus not oleracea so maybe thats why, but perhaps there’s resistance that could be crossed into other brassicas……. Hmmmm.
Oh also something ill note is the best way to get around the fungus is heavy nitrogen like urine and chicken manure regular and early one which seems to get the plant strong enough that the fungus isn’t winning the fight…. Obvious problem with that is the fungus is still surviving, but it does make me thing about nitrogen fixing endophytes for brassicas hmmm.
It might be relevant to note that brassicas and chenopods are among the few plant groups that don’t form mycorrhizal connections with fungi.
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Amazing, and makes sense, ive always thought of brassicas doing worse in fungal dominated soils and better in early succession bacterial rich soils, thank you so much for that note !!!
Perhaps that’s not true of all fungi; I read somewhere that elm oyster mushrooms make brassica species perform about 50% better, which seems to imply a mycorrhizal relationship going on there. I can’t remember the source, though.
50% better would certainly be a significant improvement!
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If they improve growth, it would be through some other mechanism ( breaking down organic matter, etc.), since Elm Oyster mushrooms are not mycorrhizal.
Also, since Elm Oyster mushrooms are decomposers, it would be hard to figure out whether the improved growth is due to decomposition of organic matter, or some direct effect of the Elm Oyster mushrooms themselves.
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I thought I remember it being specifically that species, and there are a lot of other fungi species that are decomposers, so it’s probably something special about that one, whatever it is?
But I don’t remember the source, so I could be misremembering.