Wednesday, June 4, 2014

Planting a Cover Crop Cocktail Test Plot

I've posted about my plans for this cover crop cocktail test plot before, but the quick summary for anyone that's forgotten or doesn't want to go back and read the previous post is that I'm planting a mixture of different cover crops in a small plot to see if it is feasible to plant the same sort of cocktail after wheat harvest in mid-summer for both the soil building benefits and providing winter-grazing for cattle.   

My final mixture contains (amounts are lb. per acre):  
  5 lb. sorghum-sudangrass, (or haygrazer)
  5 lb. grain sorghum (or milo), 
  5 lb. corn,
  10 lb. soybeans,   
  10 lb. blackeye peas,
  5 lb. sunflower (a black oil seed type),
  3 lb. flax,
  2 lb. okra,
  45 lb. winter wheat,
  3 lb. crimson clover,
  3 lb. canola,

The haygrazer, grain sorghum and corn will all provide a lot of bio mass to help increase the organic matter levels over time and even though it will be winter-killed, it will still provide grazing for the cattle over the winter.  Some pearl millet would have been a good addition.

Since I'm not 100% grass-fed, if there's enough time for the corn the mature, the little bit of grain from the corn will also help feed cattle over the winter.  There should also be some grain from the grain sorghum, but the birds will probably eat most of it before winter is over, while the corn will be more likely to still be available later in the winter if I strip graze the cattle across the field.

Soybeans and blackeye peas will fix nitrogen, and will also provide some grazing and grain for the cattle.  On a larger scale, I'd probably use cowpeas instead of blackeye peas, but I didn't have any cowpeas laying around so I used blackeye peas as a substitute.

Sunflowers are a decent cover crop with big taproots to break up compaction, they should attract pollinators like bees, and might allow a harvest in ideal situations (at least that's the theory). 

Flax is a complete unknown to me (I'm not even sure if it will even grow here in the summer), but I have some seed that I got from somewhere so I decided to add it to the mix, and it should attract pollinators if it grows and blooms at all.

Okra is a poor-not-even-close substitute for something like sunn hemp, but it flowers to attract pollinators, it produces a lot of biomass, and has a good taproot for breaking up compaction, so I included it in my cocktail.  If half of what I've read about sunn hemp is true, then I would use it in any future test plots or fields, it fixes nitrogen and cattle will also eat it.

Supposedly, you can plant some winter wheat, (and other typically cool season crops like crimson clover, canola, turnips, or oats) in a cocktail mix like this in the summer, it will lay dormant until the warm season crops winter kill, then the wheat will take off and provide grazing opportunities for livestock.  I'm still trying to wrap my head around this idea (planting wheat in the summer), but if it actually works it would feed a lot of cattle for little investment. On a larger scale, a combination of cool season grasses like winter wheat together with oats might be even better.

Crimson clover is included to fix nitrogen, and provide some grazing (depending on how tall it grows). Crimson clover is usually planted in the fall, so I'm unsure how it will grow when it's planted in the summer (like planting wheat in the summer, I'm also trying to wrap my head around planting crimson clover in the summer).  A combination of white clover, crimson clover, red clover, and/or alfalfa would be even better.
Brassicas like canola, turnips, radishes, etc. are supposed to work well as cover crops because they are different compared to other plants because they are able to extract "unavailable" nutrients from soil by exuding acids (that's a greatly simplified version of what actually happens).  The nutrients are then available for the next crop when the brassica crop residue starts to break down.  I still have some seed left over from an unsuccessful attempt to grow some conventional canola years ago, so I threw some into my cocktail mixture.  I'm not sure if I would use canola or turnips in a larger sized field, it would depend on whether I could find some reasonably priced canola seed being sold for cover cropping purposes, etc.

Since I'm only planting an area that's about 2000 sq.ft. and I'm broadcasting the seed instead of using a drill to plant it, I just divided all my seed amounts by 20 and weighed them all out on a scale (that extra 10% should compensate for broadcasting the seed) .   After mixing everything together in a bucket, it looked like some sort of expensive bird seed mix.
All mixed up and ready to plant
My rough estimate, after looking at a few places that sell cover crop seeds is that this cover crop mix would cost somewhere around $35-40/acre to plant, which isn't dirt cheap, but also isn't overly expensive when you consider all the benefits like increasing the organic matter levels, fixing N (possibly also increasing P and K levels), and the grazing potential.  By reducing the amount planted, simplifying the mixture, etc., the cost could probably be dropped to $25-30/acre.

I was originally planning on waiting until after wheat harvest to plant this cocktail in my test plot, but since it rained 2" a couple of days ago, giving me a decent amount of moisture, and I'm going to probably be busy right after harvest anyway, I decided to go ahead and plant my test plot.  Every year is completely different, so I decided that I'd rather get an idea about what this cocktail will do under more ideal conditions than the "real world conditions" of the summer of 2014 (which might not even apply to any other year).

Planting was a simple matter of broadcasting the mixture by hand, and then running the tiller with the tines set shallow (1-2"?) over the plot.   The weather forecast calls for rain over the next several days (why does it always wait to rain until the wheat is ready to cut?), so hopefully something should be coming up pretty soon.
6/4/14, planted cover crop cocktail
To get some totally unscientific measurements, I drove a marked stake in the middle of the plot so I can take pictures once in a while to get an idea of how this cover crop cocktail is growing. 

Now, I can only wait.  Anybody reading this can also wait along with me for exciting updates with pictures of grass growing.  But don't forget that the pictures will also show legumes and other broadleaves growing along with the grass, so even more exciting times are definitely in store for faithful readers.

Watching grass grow is exciting enough, but watching a cocktail of grasses, legumes, brassicas, and other broadleaves grow can be more exciting than words can express (or so I'm told).


  1. Your seed mix looks like some trial mix I've bought and eaten. I bet I paid a much higher price per pound than yours!

    1. I was thinking that I could grind it into a flour and bake a super-duper-multi-grain loaf of bread.

      Of course, you'd probably want to leave off the seed treatments that some of the seed has, and you might want to shell the sunflowers (sunflowers shells have a little too much fiber to produce a tasty loaf of bread).

  2. It sounds like an interesting experiment, and I would certainly find it interesting to see all of those plants growing at the same time.

    I did not know that about brassicas being able to get at nutrients other plants cannot. That makes them interesting from a cover crop/rotation perspective.

    1. There's a much better explanation about how brassicas "work" in a blog post at:

      Supposedly, brassicas also attract or are beneficial to earthworms.

      It would be nice if I could figure out how to grow and harvest canola, for both the money-making possibilities and the rotational benefits. But it might be worth as much to just grow it or a combination of different brassicas as a cover crop. I'm hoping I can figure something out with these types of small experiments.