Monday, October 17, 2011

Cover Crops and Green Manures

Last week I wrote a post about the dutch white clover I planted in my community garden plot this fall (see Cover Clover).  Renee Michelle pointed out in the comments that I didn't really explain cover crops or how they work - and they're really brilliant! - so now I'm going to.

Cover crops are grown on land that isn't being used for production with the intention of cutting and/or tilling them (in my case, turning the soil with a shovel) before they produce seeds.  What's awesome about cover crops:
  • Reduce erosion of (presumably) valuable topsoil
  • Reduce loss of soil nutrients - particularly nitrogen - due to rainwater run-off and percolation
  • Discourage invasion by weeds
  • When they're cut/tilled organic matter is added to the soil, which:
    • improves water and nutrient retention
    • makes soil like mine much easier to dig, plant, weed, you-name-it
  • Many can also be considered "green manures" because they are legumes, so they steal nitrogen from the air, which gets incorporated into the soil as they biodegrade
  • Plant root systems improve groundwater and oxygen penetration into the soil
  • Cut plant material can serve as a mulch for successive "cash" crops
I made those last two benefits red because they can't be realized if you till or turn the cover crop into the soil like I do.  But hey, pretty good, right?  And the only drawbacks are that:
  • Can become weeds themselves (if not cut in time)
  • Seeds cost money
I am sort of excited about cover crops right now because I've never had a garden as big as my community garden plot.  I am finding it onerous having to hoe so many square feet of path, particularly in mid summer, when the bare clay soil dries as hard as a rock and the wild grasses run amok.  (My plan has more path in it than strictly necessary because I feel having lots of paths helps reduce the temptation for little feet to impulsively run through a bed of newly planted seedlings.  A good trade-off if you ask me.)  The gleam in my gardening eye these days is the beginnings of a new, better, bolder plan for next year's weed-free garden!

Okay, go ahead and laugh.

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