Forage (tillage) radish as a cover crop?

For years I've used fall rye as a cover crop on our larger garden: sandy-silt mineral soil, well drained, cool/cold winters. We add rotted manure, compost, and mineral amendments during spring. With the rye as the cover, I've tilled it in, in mid spring after snow-melt and drainage time. The benefit has been the organic matter from the grass and its roots.

But I dislike the extent to which the rye comes up during the year, even after a lot of work to cultivate it in. For that and other reasons, I've been thinking of trying forage/tillage radishes as a cover, instead, as my info says it will: winter kill; loosen the soil pretty deeply; and put quite a bit of organic matter into the soil. In our climate, it would get about six weeks, at least, before hard frost would kill it. There is little to no problem with flea beetles in our region in the fall.

Do the rotting radishes tie up too much N in the early portion of the next growing season? Also, I do wonder if tilling the radishes in, in the spring, results in a field that smells strongly of rotting brassicas!?

I'd appreciate hearing about any experience (pro's and cons) of tillage radishes as a cover in an organic-cultivation system.

Joel Russ wrote:For years I've used fall rye as a cover crop on our larger garden: sandy-silt mineral soil, well drained, cool/cold winters. We add rotted manure, compost, and mineral amendments during spring. With the rye as the cover, I've tilled it in, in mid spring after snow-melt and drainage time. The benefit has been the organic matter from the grass and its roots.

But I dislike the extent to which the rye comes up during the year, even after a lot of work to cultivate it in. For that and other reasons, I've been thinking of trying forage/tillage radishes as a cover, instead, as my info says it will: winter kill; loosen the soil pretty deeply; and put quite a bit of organic matter into the soil. In our climate, it would get about six weeks, at least, before hard frost would kill it. There is little to no problem with flea beetles in our region in the fall.

Do the rotting radishes tie up too much N in the early portion of the next growing season? Also, I do wonder if tilling the radishes in, in the spring, results in a field that smells strongly of rotting brassicas!?

I'd appreciate hearing about any experience (pro's and cons) of tillage radishes as a cover in an organic-cultivation system.

They work great, but best is a mixed cover crop. At minimum a 4 way blend of several species like a cool season grass a cool season forb..a warm season grass and a warm season forb. You need biodiversity most of all.

Scott Strough wrote:They work great, but best is a mixed cover crop. At minimum a 4 way blend of several species like a cool season grass a cool season forb..a warm season grass and a warm season forb. You need biodiversity most of all.

Well, I'm wanting to try an alternative to grasses, for a change. As mentioned, fall rye is tough (just like, say, the legume alfalfa can be) and it is hard to get rid of it in spring before planting our veggies. I have a lot of years of experience with cover crops, including green-manure crops like field peas.

So one reason I was thinking of the radishes is that they would winter-kill, and be rotting in as deep organic matter in the spring/summer. At this point, I don't particularly want the growth of cover crop in the aisles between veggie rows.

Joel Russ wrote:

Scott Strough wrote:They work great, but best is a mixed cover crop. At minimum a 4 way blend of several species like a cool season grass a cool season forb..a warm season grass and a warm season forb. You need biodiversity most of all.

Well, I'm wanting to try an alternative to grasses, for a change. As mentioned, fall rye is tough (just like, say, the legume alfalfa can be) and it is hard to get rid of it in spring before planting our veggies. I have a lot of years of experience with cover crops, including green-manure crops like field peas.

So one reason I was thinking of the radishes is that they would winter-kill, and be rotting in as deep organic matter in the spring/summer. At this point, I don't particularly want the growth of cover crop in the aisles between veggie rows.

Biodiversity is a principle that is so strong, any attempt to fight it will pretty much come home to bite you in the butt. But what you could do is use the winter kill idea and still use a cover crop blend. Just use a grass like sudan grass that can't survive a freeze blended with a couple of forbs like tillage radish and sunflowers that also winter kill. To make sure there is a living root all or most the winter you could use alpine peas. Then next spring make sure to start your crop rotations early and use plenty of diverse species/guilds and companion crops.

Scott Strough wrote:Biodiversity is a principle that is so strong, any attempt to fight it will pretty much come home to bite you in the butt. But what you could do is use the winter kill idea and still use a cover crop blend. Just use a grass like sudan grass that can't survive a freeze blended with a couple of forbs like tillage radish and sunflowers that also winter kill. To make sure there is a living root all or most the winter you could use alpine peas. Then next spring make sure to start your crop rotations early and use plenty of diverse species/guilds and companion crops.

The health and abundance of our organic-garden crops this year lets me know we're not on too bad a track already (30 years on this piece of land). I agree that nature wants bidiversity - hence the presence of "weeds".

Rest assured I am paying attention to discussions of the permaculture approaches to raising food plants, the principles involved.

As mentioned in my opening post, what I'm seeking specifically is other people's experience of tillage radishes as a cover in their organic-cultivation system. That could be your experience, Scott, or that of anyone else here who feels like speaking from their's.

Joel Russ wrote:

Scott Strough wrote:Biodiversity is a principle that is so strong, any attempt to fight it will pretty much come home to bite you in the butt. But what you could do is use the winter kill idea and still use a cover crop blend. Just use a grass like sudan grass that can't survive a freeze blended with a couple of forbs like tillage radish and sunflowers that also winter kill. To make sure there is a living root all or most the winter you could use alpine peas. Then next spring make sure to start your crop rotations early and use plenty of diverse species/guilds and companion crops.

The health and abundance of our organic-garden crops this year lets me know we're not on too bad a track already (30 years on this piece of land). I agree that nature wants bidiversity - hence the presence of "weeds".

Rest assured I am paying attention to discussions of the permaculture approaches to raising food plants, the principles involved.

As mentioned in my opening post, what I'm seeking specifically is other people's experience of tillage radishes as a cover in their organic-cultivation system. That could be your experience, Scott, or that of anyone else here who feels like speaking from their's.

I get that Joel. Just giving you my experience. I use both perennial living mulches between my rows, and cover crops in a rotation in my beds. And I have used tillage radish. But I find that tillage radish alone is insufficient. That is because brassicas, especially the root brassicas, as a group are poor symbionts for Mycorrhizal fungi. One of the few groups on the planet that have this trait. Instead of feeding mycorrhizal fungi, more of the products of photosynthesis are stored in the radish root. Later as the root dies a different sort of fungi and bacteria and other soil organisms will feed. This makes your tillage radish function in a different way than other species of cover crops. Different doesn't necessarily mean bad, but it does mean that if you use tillage radish, you'll need a mixture or a cover crop blend. This way you'll experience a better balance of soil biology and less pathogenic soil organisms.

Scott Strough wrote:brassicas, especially the root brassicas, as a group are poor symbionts for Mycorrhizal fungi. One of the few groups on the planet that have this trait. Instead of feeding mycorrhizal fungi, more of the products of photosynthesis are stored in the radish root. Later as the root dies a different sort of fungi and bacteria and other soil organisms will feed. This makes your tillage radish function in a different way than other species of cover crops. Different doesn't necessarily mean bad, but it does mean that if you use tillage radish, you'll need a mixture or a cover crop blend. This way you'll experience a better balance of soil biology and less pathogenic soil organisms.

Okay, thanks Scott. So we're arriving at "less pathogenic soil organisms".

Does this mean that when you've used tillage radishes that sometimes you've found it set up a pathogenic soil-organism situation, as they rotted-in? did it infect your soil so as to harm your food brassicas (kale, cabbage, broccoli, cauliflower)? Your replies convey that you've observed certain symptoms or general effects in your beds.

Joel Russ wrote:

Scott Strough wrote:brassicas, especially the root brassicas, as a group are poor symbionts for Mycorrhizal fungi. One of the few groups on the planet that have this trait. Instead of feeding mycorrhizal fungi, more of the products of photosynthesis are stored in the radish root. Later as the root dies a different sort of fungi and bacteria and other soil organisms will feed. This makes your tillage radish function in a different way than other species of cover crops. Different doesn't necessarily mean bad, but it does mean that if you use tillage radish, you'll need a mixture or a cover crop blend. This way you'll experience a better balance of soil biology and less pathogenic soil organisms.

Okay, thanks Scott. So we're arriving at "less pathogenic soil organisms".

Does this mean that when you've used tillage radishes that sometimes you've found it set up a pathogenic soil-organism situation, as they rotted-in? did it infect your soil so as to harm your food brassicas (kale, cabbage, broccoli, cauliflower)? Your replies convey that you've observed certain symptoms or general effects in your beds.

I noticed that with either mostly tillage radish or mostly Mustard as my cover crop that I did get some bacterial and fungus diseases on the next years crops. Not just those though, any single species cover, but with tillage radish particularly. I also noticed this when I didn't grow any cover crop and just covered the whole thing with mulch. I couldn't explain it until I watched a USDA SARE educational vid on multispecies covers being researched at the Burleigh County Soil Conservation District in Bismark ND. A guy named Ray Archuleta has given many educational talks about what he is doing for farmers like Gabe Brown. Now that's from the conventional side of agriculture as it tries to move toward soil health and sustainability. I always was an organic farmer, so I already had pretty good soil health, got into permaculture relatively recently, but I learned a lot from those conventional guys and used that information to bump my organic production up yet another notch. Since switching to multi species covers and perennial living mulches, I have not seen ANY of the fungus and bacterial disease spreading like I occasionally saw just using traditional organic methods and single species covers.

Before I would see a plant get a disease, and watch that disease slowly spread, then after infecting and sometimes killing a dozen or so plants, the disease would gradually die out. I was happy with that since I used no sprays and it stopped itself just by natural means. But now when a single plant gets a disease, it stops right there, and even sometimes the original plant pulls out of it and finishes normally. It really is an interesting effect. Now I know the reason is the mycorrhizal fungi and the diversity of species built in the root zone. Different plants have different roots and you need a mix to build that balance the roots support with their exudates. This has by the way been a very exciting branch of scientific research. Mycorrhizal Fungi: The World’s Biggest Drinking Straws And Largest Unseen Communication System

ETA PS Now I really like the tillage radish much better. Because I use it with a blend instead of by itself.

Scott, I appreciate the time and thought you've put into replying. I'm going to check into some of the resources you've mentioned.

Joel Russ wrote:Scott, I appreciate the time and thought you've put into replying. I'm going to check into some of the resources you've mentioned.

This might help. I realise it might not be based on organic and/or permaculture, but the principles of soil health are the same. It was really easy to adapt this to my systems.

Joel, I'm an organic row crop farmer and have amazing results with the following mix planted at the time of year your referring to- radish, field pea, oats, buckwheat. All freeze kill but lots of time to make organic matter and work their soil magic. Much easier to incorporate or no till than rye. Keep on growing!