Wednesday, 29 June 2011

Cover Crops, Not Just for Farmers

Over the past couple years I've been experimenting with cover crops in my garden. So far I've planted: crimson clover, hairy vetch, winter rye, buckwheat, fall cover crop mix, spring cover crop mix and various other legumes. Cover crops play a variety of roles in your garden. Use them to protect soil during the winter, they prevent erosion while improving it. They can also help control nematodes and mitigate other soil issues. They work beautifully as a suppression crop on a newly made garden keeping the weeds at bay.
Crimson clover is my favorite, it's a beautiful cover crop. The first time it bloomed in my garden 2 years ago I knew I'd be using it for years to come. It grows quickly, smothers weeds and brings up nutrients for future crops - all this while looking fabulous!
This past winter I experimented with an overwintering cover crop mix. It contained: winter rye, hairy vetch and crimson clover. It started growing last fall and reached a height of about 6 inches. Throughout the winter it went dormant and protected the soil. This spring as soon as it warmed up slightly the rye started growing. Soon enough the vetch joined in and before long it was almost 4 feet tall.
I chopped it down last week as the vetch was just beginning to bloom. Using pruners, I cut it down in 6-8 inch segments and then went to work digging it into the soil. Before long my neighbor came over inquiring if I was wanting to work up the soil. He'd just purchased a new toy and was itching to use it. A few minutes he returned with his new tiller and starting working the cover crop into the soil. Mr Chiots came out and did the rest while I chatted with our neighbor.
I source my cover crop seeds from Johnny's Selected Seeds. They have a great selection of single crops and mixtures, just about everything you'll ever need. Here's a great chart from them to help you chose the right crop for your application (click on the image to view larger, readable version that you can save if you want to).
It's quite amazing the difference a cover crop will make when it comes to improving the soil. It takes patience because you have to wait for it to grow, buy it's certainly an inexpensive way to amend large areas of soil. I'm looking forward to trying a few other varieties. I currently have mustard seeds and I'm looking forward to trying a turnip as well. Now that I have a new large garden they'll come in handy for smothering weeds on the newly cleared land and they'll improve the soil in the process so it will be ready when it comes time to grow vegetables!

Do you ever use cover crops in your garden?


LindaG said...

This is something I have been wanting to do so I was really glad to read your post. Thanks for the information and the links. I'll definitely be checking this out. :)

Myrnie said...

My dad is trying to convince me that cover crops in raised beds are bad ideas- I'm just planting weeds, it's better to hand pull. Why is he wrong? Are the cover crops hard to get rid of in the spring??

Joshua said...

@Myrnie: If you're doing raised beds, you're probably also adding a lot of compost or other fertilizer. Raised beds are often also made with a custom potting mix or screened topsoil, which tends to have fewer weed seeds to begin with. It's my opinion that cover crops are less desirable in raised beds for these reasons. The main advantage of cover crops is:

1) Adds organic material to the soil, both from root die-back and from incorporating the green material itself in the spring.
2) Smothers and outcompetes weeds.
3) Soil retention / erosion resistance.

None of these are really issues to most raised bed gardeners. Organic material is added in the form of compost. Weeds are much less of an issue because you didn't start out with ground that had generations of weeds growing and dropping seeds in it. Additionally, raised beds are usually planted intensively, so your vegetables themselves are shading out the weeds. Finally, erosion doesn't really happen with most raised beds.

In short, I think your dad may be right. It's not that you couldn't do cover crops in raised beds, just that raised beds usually go with a different set of approaches to solving the problems of weeds, fertilization, and erosion control.

Myrnie said...

Thanks- when will i learn that Dad is ALWAYS right?? :)

Amy said...

Thanks for the cover crop info - the chart looks like something I will be keen to come back to! We've thought about cover crops for our small suburban garden but haven't got any further than the you think they'd be just as valuable covering a few m2 as your larger areas? We grow all year round but I'm finding the soil really, really needs some help so am wondering if a cover crop might be one way to do that - avoid the temptation of planting an edible winter crop, cover the soil, and hopefully improve it's condition for the next crop. Amy

Donna OShaughnessy said...

Really great post. "Weeds" are important. Great photos too

Robert said...

I'm currently trying a cover crop of weeds in a small area. I ought to investigate these crops, as not all of them will self-seed the way annual weeds do!

I use mulch, mostly grass cuttings, which either gets taken down by worms or dug in; I imagine it has a comparable effect on the soil.

smallgardendesign said...

Thanks for sharing the cover crop information. I ought to investigate these crops, as not all of them will self-seed the way annual weeds do!
small garden design

Marie said...

We use cover crops on our raised beds for all of the reasons you mention. We think they are very valuable. We don't till them under but cut them down and leave them as mulch. We have had great success with this no-till approach for improving our soil and topping up our beds over time.

a lovely additional use for the crimson clover is that it makes a delicious and healthy syrup to add to water, sparkling water, tea, pancakes or whatever. I use the recipe from
"A Taste of the Wild" by Blanche Pownall Garrett. A lovely old-timey practice.

Rosa said...

I had really good luck with buckwheat last year. I have a large mixed perennial flower bed that had gone to mostly echinacea and snakeroot weed. We dug out a ton of those, clumped the things that were left (including two echinacea beds, 3 foot square) and were going to weedcloth and mulch the rest, but the shapes were too complicated. So I planted buckwheat groats from the bulk bin at our coop.

They were lovely, constant small flowers even in nearly full-shade areas, and even though technically our growing season isn't long enough for buckwheat, I have a *lot* of volunteer buckwheat this year.

frazzledsugarplummum said...

Great Post. I love crimson clover and use it extensively. On more open areas I have used a mixed bag of seed. I have used it on raised beds some as cut and drop and others pulled out. The following crop was marvellous.