Growing Cover Crops

Growing Cover Crops

Part of Ep. 1503 Focus on Foliage

Horticulturist Dr. Astrid Newenhouse teaches viewers how to control weeds in the garden. She suggests using cover crops, which also are great for improving soil structure and increasing fertility.

Premiere date: Jul 25, 2007

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
This is buckwheat.  No, it's not for pancakes!  This is grown as a cover crop.  We are in rural Gotham.  And I'm with Dr. Astrid Newenhouse to learn more.  Astrid, I know cover crops are beneficial for the soil.  I'm not sure where they came from.  This is not a new practice, is it? 

Astrid:
No, it's a really old practice, Shelley.  Three thousand years ago in China, people used cover crops.  The Greeks and Romans used them.  They were popular in the U.S. before chemical pesticides, herbicides and fertilizers came. 

Shelley:
In general, this is also called a grain manure? 

Astrid:
Yes, it's a crop that you grow to improve your soil health and to cut and turn under, to till in. 

Shelley:
You've got a couple different samples for us to look at.  And each one has different benefits. 

Astrid:
Right, the buckwheat here, I would choose if I had a weed problem in my garden, or if I wanted just a quick cover. 

Shelley:
So, it's not just for soil health, but weed control. 

Astrid:
Yes, buckwheat comes up really quickly.  It smothers weeds.  And it’s also allelopathic.  It puts out a root poison that prevents other plants from growing around it. 

Shelley:
Even quack grass? 

Astrid:
Even quack grass. 

Shelley:
Okay, this is the one that I'm growing.  When would I plant this? 

Astrid:
You would plant this any time you have bare ground.  Like here, we’re in my dad's vegetable garden there's a little piece of bare ground, so late summer, early fall. 

Shelley:
Bare ground because nature loves a void.  If we don't plant something, nature will put in those weeds, quack grass, thistles. 

Astrid:
Much rather have it be something you can manage and control, that also adds other benefits of improving soil aeration, making soil more fluffy, bringing organic matter into the soil.  And helping create an environment for beneficial micro-organisms and earthworms.  It's great stuff, Shelley. 

Shelley:
And here you've got the first stage of the planting, the young ones.  Here you've got the pretty flowers.  Will we get buckwheat seeds from this that we can make pancakes with? 

Astrid:
Absolutely do not let this go to seed!  At the flowering stage, you want to start mowing this off, because once that goes to seed, then that becomes a weed problem in your garden.  So, cover crops, you never ever let them go to seed.  Turn them under. 

Shelley:
You've got one that's maybe a little easier for beginners who are a little worried about starting a new weed problem. 

Astrid:
These are oats.  And the cereal grains: oats, wheat, rye, are excellent cover crops, especially for fall planting.  So, in fall, which is actually late summer in Wisconsin, you would plant these.  Then, let it grow up and some of them, like wheat and rye, will come back in the spring.  Some, like these oats will die out over the winter.  But whether or not they come back or die out, the stubble still helps prevent soil erosion and add organic matter to the soil. 

Shelley:
This is one we'd plant in late summer and till under in the spring.  And it's awful tall. 

Astrid:
Yes, it's much easier to turn a cover crop under if you mow it down first, shorten it.  Either with your mower set on high, or with a grass hook, or a string trimmer. 

Shelley:
Well and then you've got one more.  This one is wonderful, too, because it actually adds nitrogen to the soil. 

Astrid:
Isn't this beautiful? 

Shelley:
This one's pretty.  This is hairy vetch.  It's a legume, so it lives symbiotically like all legumes with the bacteria in its roots.  And that bacteria grabs nitrogen from the air around the root and brings it into the hairy vetch.  So when you turn this legume under, it releases that nitrogen back into the soil. 

Shelley:
So it's not releasing nitrogen now.  We turn it under and that's what does it.  When would we plant this one? 

Astrid:
This one, you would plant also in the late summer, early fall.  This is a very slow growing one.  This is not the best choice for weed control.  But this is a great choice for adding fertility to your soil and lots of organic matter.  And this will over-winter.  So next spring, it'll come up again and that's when you would turn it under. 

Shelley:
We either plant them, most of these, in late summer, early fall.  The buckwheat we plant anytime we have a little patch of bare ground.  And then we shorten them and we till them.  Is there any special trick to planting them? 

Astrid:
A lot of them have small seed.  And you can either hand-broadcast, or you can use a cyclone broadcast spreader, depending on how large your area is.  Rake them in lightly and then keep them moist until they come up. 

Shelley:
Excellent, thank you. 

Astrid:
You're welcome. 

Shelley:
These are some great ideas to improve your soil’s health and make the weeds a little unhappy. 

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