Winterkill of cover crops in zone 6

The Walden Effect: Farming, simple living, permaculture, and invention.

Winterkill of cover crops in zone 6

Oat cover crop is mostly winterkilled by end of January When I summed up 2010's no-till cover crop experiments, the only question left was how various crops would winterkill here in southwest Virginia. Now that the traditional coldest month of the year is just about over (and the garden is finally free of a coat of snow), I went out to check on the state of the cover crops. For those of you who haven't been following along, I was looking for the opposite of what gardeners usually aim for --- dead plants so that I won't have to till them in. Here's what I saw:

Oats have a green leaf here and there, but look pretty much dead. If any of the plants sprout back up when warm weather comes, it won't be hard to mow them down, but I suspect I won't have to do that. It looks like the remains of the oats will make a good mulch for the coming growing season.

Oilseed radish winterkills and starts to decompose

Oilseed radishes have a wisp of green here and there, but the plants are clearly dead --- I can easily tear the huge taproots apart with gentle pressure. Inside, the roots are soft, spongy, and mostly decomposed already. The plus side is that the biomass will probably have melted into the soil enough that crops I plant in old oilseed radish beds can use the nutrition this coming year. The flip side of the coin is that I'm going to need to mulch the oilseed radish beds soon because bare ground will quickly grow full of weeds now that the snow is gone. As a final note, I feel that I should mention that the stench most websites report from their decomposing oilseed radishes didn't materialize in my garden, perhaps because the radishes spent so long under a coat of snow.
Annual ryegrass is still mostly green, so it looks like I'm going to need to find a way to kill it. I've read that ryegrass is easy to mow-kill, so that will be my first option.
Buckwheat is frost tender and is long gone.
Barley is still green, despite the fact that I planted it in late October and the plants only got a couple of inches tall before growth ceased for the winter. I'd be tempted to leave it alone and see what it does this spring, but the barley is located in beds that are slated to go back into early spring vegetable production. So I'll probably just weed or smother the baby barley out.
Crimson Clover is still bright green and small. Unlike the other cover crops I'm trialing, the clover is a legume, which means its benefit isn't so much adding biomass to the soil as adding nitrogen. Some people have good luck leaving crimson clover as an intercrop among large vegetables, so I'm going to see if the clover can share beds with broccoli and other large crops this spring.

Based on this winterkill data, I've got some changes to make for next year. I think I'm going to delete ryegrass from my winter cover crop rotation, plant barley and crimson clover in the shady part of the garden where I don't start vegetables until May and could allow the cover crops to mature in the spring, plant oats where I want a mulch the next summer, and plant oilseed radishes where I want to direct-seed early spring crops. It's great to finally be wrapping my head around the niche of each cover crop.

Our homemade chicken waterer keeps your coop clean and your chickens healthy.