First Attempts at Cover Crops

So this year is really about building up and enriching my soil. I'll be totally thrilled if my plants do well too. As part of my research, I've come across what are called cover crops and sometimes they are referred to as green manure. The terminology just refers to the ways you intend to use the crop. After reading lots and lots I decided on a couple of crops to try out this year:

• Field Peas
• Buckwheat
• Crimson Clover
• Hairy Vetch

The main purposes of a cover crop are:

1. Cover empty ground
2. Prevent erosion
3. Prevent washing away of nutrients
4. Break up compacted soils
5. Return nutrients and organic matter back to the soil.

Typically cover crops are used on large farms, but what works in large scale, usually works well in small scale too. I didn't find a ton of information about using cover crops specifically in a raised garden, suburban setting so I think I've got a lot of learning and figuring out to do this year.

Legumes such as Field Peas, Crimson Clover and Hairy Vetch are Nitrogen fixing plants. That means they convert nitrogen into the air into nodules on their root systems that can be used by roots of plants. The key to getting the benefits is to kill the plant before it uses the nitrogen it has stored into bearing the fruits...or seeds. While field peas are edible if left to seed, I lose the benefit of nitrogen fixation if I let them go that far. I intend to use all of these crops as green manures this year.

I chose buckwheat because it is VERY fast growing, loves the heat and produces an abundance of biomass. In our area of Texas we can get two warm seasons of productive growth: March-Juneish and August-Decemberish. When many of my plants are spent but before it is on the downswing of summer where I can start a fall crop, I tend to have barren soils for a month or two. During this time the sun just bakes and dries out the poor earth and it is hard and terribly deficient by the time fall plantings come around. This is where Buckwheat will come into play. I have just enough window of time to grow a season of buckwheat and cut down before fall planting adding lots of organic matter for the fall crops to consume. I hope it works out as well as I imagine it will.

Field Peas will be my companion crop for the corn this year. Something I didn't know about corn is that is is a nitrogen hog. That explains why my second crop of corn never did well or did anything, the first crop consumed all the nitrogen that was in the soil and the second crop got nothing. My corn so far has sprouted to about 4 inches. I still have it covered in bird netting because the birds and squirrels will still dig it up at this point. I removed the cover, mounded the rows of corn for extra stability as they continue to grow and then broadcast my field peas between the rows in all the rest of the available spaces. I raked it in lightly and then watered the whole bed very well and replaced the bird netting. Unfortunately, while I meant to inoculate my seeds, I didn't...so while they won't fix the maximum nitrogen, they still should do pretty well on their own. To inoculate the seeds means that you coat them with a specific strain of powdered bacteria. This particular bacteria helps the plant to fix the nitrogen from the air. It's some kind of symbiotic relationship. I don't know a whole lot about it other than you are supposed to do it. My other legume seeds I bought have already been inoculated.

I will let the field peas grow until they flower and about a week after flowering, I'll cut the plants down which should kill the plants and any nitrogen in their roots will be released into the soil and the worms and other organisms in the soil will feed on the plant matter which will also provide cover to the soil to help with erosion and compaction from the rain and sun. That's the plan anyway. All the directions I've found for killing cover crops speaks of "mowing" them down. Well that doesn't work so well with a raised bed, not to mention it would take me a week to dig out the mower from the shed since we pay someone to cut our grass. I plan to just use my manual hedge shears to hack away at the plants from top to bottom. I hope that'll work alright.

The Crimson Clover and Hairy Vetch will be my cover crop from Nov/Dec-Feb/March. I've read lots of good things about planting tomatoes into Hairy Vetch after it is cut down. Works great as mulch and fixes the nitrogen that the tomatoes need. The Clover is exceptionally good at creating biomass and is pretty to boot. I may not do a fall garden at all this year except maybe some collard greens, a few broccoli, and carrots, that's all I ever end up using anyway. 

I think keeping my beds covered and fed in this way over the downtime will really make a difference in my soil. I'm hoping it'll lower my physical labor requirements as well since I won't have to do so much breaking and turning of the dirt, the plants and worms should keep everything conditioned well enough all I'll need to do is plant right into the mass.