Cover Crops

After tilling and watering the area, it was time to plant a cover crop. For those who don't know, a cover crop is plants don't really have any value (food or money wise) but they are supposed to maintain or improve the soil. I originally wanted to get a nitrogen fixing legume. Nitrogen fixing is the process of using symbiotic bacteria in the soil to take nitrogen out of the atmosphere and put it into the soil where other plants can use it. Most vegetables use up quite a bit of nitrogen, which is the main component of most fertilizers. When you use a nitrogen fixing cover crop, you dramatically reduce or eliminate the need to artificially add nitrogen. I started doing internet research on cover crops, focusing on nitrogen fixing plants. By the time I got my soil samples back telling me that I have plenty of nitrogen in my soil, I already had my heart set on a specific plant....Hairy Vetch. Its one of the few (maybe only) nitrogen fixers that can survive the winters around here and produce a useful amount of nitrogen during the off-season months when there are no vegetables planted. Besides...I like the name. The Vetch was also chosen because its relatively easy to kill by tilling it when it is flowering in the spring. Thats a good thing so that it doesn't turn into a weed in my garden next year. Hairy Vetch grows quite a bit of mass in not a long time, so when it comes time to till it into the soil, it provides a lot of decomposing organic matter in the soil (a good thing). Lastly, the Vetch has a moderately deep tap-root that should burrow into that hard clay layer and help break it up somewhat.

Most websites recommended pairing the Hairy Vetch with another cover crop. The other crop would ideally grow quickly in the fall (when the Vetch grows slowly) and provide a layer of thermal insulation for the Vetch during the winter. A friend of mine who is a thermal engineer is fond of saying that everything in life is a thermal problem. I decided on winter oats. Unfortunately the company that I ordered from (Peaceful Valley) was out of winter oats at the time. So I decided to go for something similar like cereal rye. However, unlike the oats, the rye survives the winter, and I was worried about the grassy plant becoming a weed that would be difficult to kill. I saw something called annual ryegrass. Assuming it was similar, but an annual (dies off each year), I purchased that. I found out later that its a completely different species and rather different, but at least its supposed to grow quickly in the fall and then (hopefully) die. I got a pound of each. I found recommendations to plant 10-15lbs of ryegrass with 25-40lbs of Hairy Vetch per acre (43,560sq ft) for professional operations. I have maybe 400 sq ft to plant (less than that gets really good sun), so that comes out to maybe 1/8lb of ryegrass and 1/3lb of Vetch.

Since this is far from a professional operation and I wasn't sure about how well I was going to be able to cover the seeds and get them to germinate, I decided to aim for 1/3lb of the ryegrass and 1/2lb of the Vetch. They came in 1lb bags, so I figured I'd just shake the bags sprinkling the seeds on the dirt. I didn't do so hot with the ryegrass, ending with only about 1/3 of the bag left. Hopefully the ryegrass won't be so dense that it smothers the Vetch. For the Vetch, I had to innoculate the seeds first with bacteria. Remember the symbiotic relationship from above? The bacteria is not present in all soils, and especially where there haven't been any nitrogen fixing leguminous plants growing there in a while (peas and clovers are examples of other legumes). So anyway, I bought the bacteria with the seeds. You basically just wet the seeds and coat them with the black, powdery dried bacteria. I did that for half of the bag, so I got the right amount of Vetch seeds and I spread them around the garden area. To cover the seeds, I took a garden rake and basically "teased" the top layer of dirt to mix in the seeds. Then I sprayed a bunch of water over things again. Its been very dry around here for the last month and a half after having a record cold and rainy first half of the summer. After watering, I noticed some of the Vetch seeds on top of the soil, so I re-teased the top layer. Then I decided that it still needed more water, and I thought it would reduce water evaporation if I finished with the smoothed surface after watering compared to the very rough surface after teasing. So I went through a couple of cycles of watering and teasing, ending with a watering. There were still Vetch seeds visible on the surface, but I just decided to cross my fingers.

So to summarize:

2/3 lbs annual rygrass and 1/2 lbs hairy vetch (with innoculant) were planted on september 12th.