Friday, September 23, 2011

Starting Garden Cover Crops on the Right Foot

I have a blogging conundrum.  Either gardeners don't read blogs, or don't comment on them, or specifically don't read or comment on mine.  For that reason, I thought I'd switch up the format of my next few garden entries to be a little more educational and a little less, "Yeah, so I tried this, it worked.  Yay."

It's late September in Maryland. The squash and okra are done and gone.  Tomatoes and peppers following quickly.  The only strong production really going on is sweet potatoes, and soon they'll be gone too.  It's time to plant cover crops for the winter.  Sure, we'll do some greens and beets and onions and garlic.  But I want to keep my soil nice and safe for next spring.

If you're reading this, you probably already know all about cover crops and how they are the cheapest and easiest way to protect your soil and stop your soil nutrients (and your soil) from running out on you over the winter months.  If not, just take a cruise through my cover crop and no-till blog tags.   There are tons of reasons why people plant winter cover, including those listed above.  But getting your urban or suburban garden to actually meet those objectives is a lot more complicated than just throwing down some deep-rooting hardy seed.  Here are the basic steps.

1. Know what cover crop species you're planting well in advance of the planting date.
Do your homework - your state extension service is a great resource for choosing species and for planning for planting dates.  Here's an example from Indiana:
Dubois County Soil & Water Conservation District's Cover Crop Web Tool
2. Prepare the soil.  If this is a new garden (currently under concrete, gravel, turf, etc), you will need to do a lot more than lay down old newspapers (an old hippy method) to get the soil ready to accept high quality cover crop species.  If you have to till the garden just once, you have not forsaken Mother Earth.  You may want a soil test (always recommended if you are going to grow food), or you may just go ahead and incorporate tons of compost, wood chips, and manure under the assumption that the soil is worthless nutrient-poor.

For existing gardens, just clear out dead summer crops, kill any and all pervasive weeds, and rough up the surface to the planting depth (usually less than 2 inches), either in rows or across the entire bed.  If you have a seed drill, that's even better, but a seed drill doesn't punch through rocks, bricks, or mulch in your garden, so make sure to remove all debris. The key here: make room for your new seeds.
The bed on the left has been (largely) prepared for winter cover crop seeding.
The bed on the right contains late-growing sweet potatoes.
Oats and peas for winter 2011-2012
3. Set aside time to plant.  Especially in the case of winter cover, you are making a lasting investment for very minimal effort.  Do it right.  Take a few hours.  You won't have to fuss over it for another 4-6 months.

4. Plant based on real information, either from the seed dealer or from your local extension agent.   For example, based on your garden's soil, do you need to buy legume innoculant?  Sometimes, blog information can be helpful, too.  Example: my cover crop test from last winter.   It's not scientifically validated, but a decent guess at what you're getting yourself into.

5.  Don't be afraid to experiment.  Try different planting methods. Different species.  See what happens.  One tip: unless you love spraying herbicide on your garden, don't use cover crops that will not succumb to spring mowing, especially if you are interested in no-till, as I am.   If you search the internet for "harvest green manure" followed by the species you planted, you'll see how to deal with the greens next spring.

6.  Give your soil every possible advantage.  That's what this is about, right?

a. If you plant winter cover in rows (as I did), backfill the rows with compost instead of garden soil.

b. Mulch the garden very lightly once the cover crop is 6-8" tall.

c. After you've planted it (ideally, before), read up on your cover crop species - how deep does it root? How effective in removing soluble nutrients? Protect from rain and snow runoff?

7.  Don't be despondent if the cover crop looks weak in the spring.  While a poor cover crop may not accomplish all of your goals, if it "sort of lived" through the winter, your soil is better off than it would have been without the cover crops. Every pound of soil you keep in your garden is a pound that doesn't end up in your local creek - and a pound of topsoil you don't have to buy at your local garden center.
My various covers from Spring, 2011. Look at those peas!!!


Anna said...

I'm a *lazy* gardener, so I feel obliged to add --- you don't need to do much to make cover crops work. At this time of year, I rake back mulch and/or pull out the finished vegetables and weeds, don't touch the soil, scatter oats on the soil surface, and very lightly sprinkle straw on top (the way you would if you were seeding a lawn.) If the seeds are good, I get a great stand of cover crops with next to no work.

This method worked well for me with oilseed radish (who don't even need the mulch --- they sprout nearly immediately after the first rain and put down roots fast), buckwheat, cowpeas, and field peas. So, no need to work up the soil and make rows.

Kirk Mantay said...

You raise two good points:

1. Many ways to skin this cat, and

2. When it comes to soil conservation, doing something is usually better than doing nothing.

It comes down to 2 things - your starting point, and your goals. This is something I advocate with conservation and garden projects all the time. I should have explicitly gotten into it for this post....and I didn't.

For your garden, you expect moderate benefits from cover crops, for minimal effort, and you're obviously starting with a decent, weed-free, concrete rubble-free bed. You are going to be successful!

For my garden, I expect near record-breaking performance from my cover crops because I expect the soil to be perfect next spring. My beds are only 0.5 - 1.5 years old, and still have the odd tree branch/giant rock/piece of brick stuck in there. My starting point was atrocious. I'll also probably be successful, but will work harder than you to achieve what "success" is for my garden.

And being in either your position or mine (or 100 other permutations) is a great way to be!!!

biobabbler said...

Hee. I'm reading this post thinking, Oh, yeah, I should do that. Then I read "Know what cover crop species you're planting well in advance of the planting date."

Oh, well. =)

Back to my "Suppress your inner perfectionist and get SOMEthing done" rule. I'll have to look stuff up.

THANK YOU for this SUPER timely (and apparently needed) reminder!

Kirk Mantay said...

Ahem, my number 7 points to "something is better than nothing."

Throw something out there. Something non-invasive. It's a good, easy thing. We're also in Zone 7 so we may or may not be ahead of your planting zone.

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