Growing Green Manure Crops – Practice on the Small Scale First

“Green manure” cover crops are grown and then plowed under, or incorporated, into the soil.  The green vegetation feeds soil critters, makes the soil nice and crumbly, and most of the roots become organic matter.  Green manure crops are a good, cheap fertilizer because 95% of the vegetation comes “free” from photosynthesis, and the 5% that contains minerals from the soil is returned to the soil, in even better plant form.  This post describes the benefits of practicing growing green manure crops on the small scale first… 

Rich made a good comment on my last blog post.  He grows small scale garden plots of green manure crops and takes note of their attributes, both good and bad.  After I read his comment, I realized this is the way to go.  Instead of spending hard-earned money on 25 acres’ worth of cover crop seed that I’ve never grown before (and risking crop failure), it’s wise to practice growing these crops on the small scale first.

My previous blog post explained our rotovator woes and our newbie farmer puzzlement over the poor germination of our rye & vetch winter cover crop.  In early September, I also planted some rye and vetch on the small scale – in our veggie garden beds.  Because these plants germinated wonderfully, I know the poor field germination is not the seed’s fault.  I’m also noticing different growth patterns of the rye and vetch that were planted at different dates– valuable info for how these two germinate and grow in our climate as winter approaches. 

Rye & vetch winter cover crop with dead buckwheat stems. Rye and vetch planted 9/9/11. Pic taken 11/20/11.

Rye and vetch’s interaction with buckwheat is another valuable piece of information I gained.  In the veggie beds this summer, as harvested produce left bare spots, I planted buckwheat to quickly cover the soil.  By mid-September, most of the veggie beds were full of buckwheat.  A lot of it had already made seed.  I decided to hoe it down into the topsoil so it could improve the soil’s texture and feed the critters.  I let the soil digest it for a couple of weeks, then planted rye and vetch.  Before the rye and vetch germinated, a lot of buckwheat from the hoed-in mature seeds started coming up.  I thought, “Ah oh, the buckwheat might out-compete the rye and vetch!”  This turned out to not be the case.  Check out the picture – the rye and vetch germinated with gusto, the buckwheat died quickly after frost, and the vetch started climbing up the buckwheat stems.  Yay, it worked!

So next year, I can use my buckwheat know-how to confidently plant it in the fields as a summer cover crop, then rotovate it into the soil, and then (after checking soil fluffiness) plant rye and vetch with no fear of it not germinating because of buckwheat competition.  Knock on wood, because this sounds like I’m setting myself up for another “lesson”!

Because we had trouble getting rye & vetch to germinate after rotovating sorghum sudan, I’m going to re-create this in a few veggie garden beds this summer and see what happens.  If the rye and vetch germinate just fine, I know it’s not the weed-killing attributes of sorghum sudan.  I can narrow the germination problem down to fluffy soil or the toad-strangler rains we got from Tropical Storm Lee. I also plan to practice growing other cover crops that look enticing to me, such as yellow blossom sweet clover and millets.  I’m looking forward to gaining this low-risk experience on the small scale next summer.  Thanks for reading!


4 responses to this post.

  1. Posted by Rich on November 21, 2011 at 11:23 pm

    There is a blog that details different cover crops (hence the name) at:

    It mainly deals with crop production that includes herbicides and fertilizer, but most of it should apply to your farm if you are looking for ideas for different cover crops to try.


    • That site is very informative – thanks! Looks like he hasn’t written about sorghum sudan, maybe this is a sign?


      • Posted by Rich on November 25, 2011 at 5:49 pm

        That site is geared more towards the Midwest corn and soybean growing areas, so their cover crops would be more cool season types of cover crops designed to fill a void in between their summer crops.

        I know that if I could consistently grow 150-200 bu. corn, I wouldn’t be planting very much sorghum-sudangrass. But, most of the cool season cover crops observations should apply almost anywhere.

        Have you ever seen Rodale’s organic no-till website?

        I noticed that they had a page about various planting dates for hairy vetch, some cover crop ideas, along with their roller-crimper method that looks pretty interesting.

      • Thanks, that makes sense. Especially with great corn prices right now, it doesn’t make money sense to replace sorghum sudan with corn if you get those good Corn Belt yields. I think sorghum sudan’s advantage to corn and soy farmers is its ability to wipe out roundup resistant weeds – that’s what it did in these fields this year anyway, knock on wood.

        Yes, I’ve seen Rodale’s roller crimper website – very cool! Especially for farmers who want a thick mulch layer.

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