Green manure is a crop grown to add nutrients and organic matter to the soil. I chose this method for two of my garden beds this year. I feel that this could be a good option in a grid down situation where traditional fertilizing methods are unavailable and the convenience of a tiller might not be had. Just as well, this is a nice organic rotational method that doesn’t require heavy lifting or shoveling. Cover crop seeds can be stored just like any other seed.
I started my experiment with hairy vetch. Hairy vetch is a legume that forms tiny nitrogen fixing nodules on its roots. This nitrogen can help to amend soil which has been depleted in the previous season. Cover crops are generally planted in the fall or early spring and then cut down before planting that year’s crop. Though by planting in the fall you will effectively cut down on erosion during the winter. Some turn the remains in the soil with a tiller, but I chose to leave the cuttings as a mulch. As I stated above this is my first experiment and just many of us, I am still learning. Here are my results thus far.
I planted the hairy vetch back at the end of October. It grew a couple of little scraggly vines, but nothing to impressive before the weather got to cold. The hairy vetch wintered over fine without a noticeable hiccup and began to grow again as the weather warmed in late winter. One thing that I must mention, in our area of zone 6 we had an unusually warm winter with minimal snow. I am not sure yet how this affected our results as I have not yet grown the crop through a strong winter. After the weather warmed the vetch shot up quickly and was barely effected by frost. Shown in the picture above is the hardy plant with early spring flowers. The farmer down the street keeps honeybees and I like to imagine that the bees which covered these flowers may be his. And yes it’s delicious honey!
I relate cutting the hairy vetch much to the effect of removing carpeting. You are actually rolling as you go. I started on the end of the bed cutting the stems as low as possible, rolling as I went. I used a machete because that is what I have that is somewhat flexible (and not expensive). A shorter knife with a flexible blade may work better.
Once reaching the end I went back over the ground removing any stragglers. As I stated above you don’t want any of it going to seed. You will see some green on the bed in the picture most of which are stems and a little clover. When unrolled, the vetch should block the sunlight keeping these stems from growing further. (I hope.)
Rolling the vetch out is not an exact science. As you might imagine it was too short to go to the end of the bed. I was actually able to start at the beginning giving a little tug and move the whole “rug” down a little further. Then I trimmed up the edges that hung over the walkway and used the trimmings for the bare spots, effectively creating an entire blanket of green mulch for the entire bed as seen above. When ready to plant, I will just pull back the mulch and plant directly into the soil.
So far I have been impressed with the ability of the cover crop. Maintenance is low (never watered) and it has done an outstanding job of suppressing weeds. I think a little bit of well composted manure spread on top after planting would do great. I will definitely be adding hairy vetch to the seed bank.
As always, please direct any comments below.