Using a Buckwheat Cover Crop in Raised Bed Gardens

by | Sep 28, 2020 | Beneficials, Best Management Practices, Butterflies, Cover Crop, Eggplant, Fertilizer, Insects, Integrated Pest Management, Mulch, Pollinators, soil management, Tomatoes, Vegetable Gardening, Weeds

2020 has not been the most pleasant year in many ways.  However, one positive experience I’ve had in my raised bed vegetable garden has been the use of a cover crop, Buckwheat (Fagopyrum esculentum)! Use of cover crops, a catch-all term for many species of plants used to “cover” field soil during fallow periods, became popular in agriculture over the last century as a method to protect and build soil in response to the massive wind erosion and cropland degradation event of the 1930s, the Dust Bowl.  While wind erosion isn’t a big issue in raised bed gardens, cover crops, like Buckwheat, offer many other services to gardeners:

Buckwheat in flower behind summer squash. Photo courtesy of Daniel Leonard.

  • Covers, like Buckwheat, provide valuable weed control by shading out the competition.  Even after termination (the cutting down or otherwise killing of the cover crop plants and letting them decompose back into the soil as a mulch), Buckwheat continues to keep weeds away, like pinestraw in your landscape.
  • Cover crops also build soil. This summer, I noticed that my raised beds didn’t “sink” as much as normal.  In fact, I actually gained a little nutrient-rich organic matter!  By having the Buckwheat shade the soil and then compost back into it, I mostly avoided the phenomena that causes soils high in organic matter, particularly ones exposed to the sun, to disappear over time due to breakdown by microorganisms.
  • Many cover crops are awesome attractors of pollinators and beneficial insects. At any given time while my Buckwheat cover was flowering, I could spot several wasp species, various bees, flies, moths, true bugs, and even a butterfly or two hovering around the tiny white flowers sipping nectar.
  • Covers are a lot prettier than bare soil and weeds! Where I would normally just have either exposed black compost or a healthy weed population to gaze upon, Buckwheat provided a quick bright green color blast that then became covered with non-stop white flowers. I’ll take that over bare soil any day.

Buckwheat cover before termination (left) and after (right) interplanted with Eggplant. Photo courtesy Daniel Leonard, UF/IFAS Calhoun County Extension.

Now that I’ve convinced you of Buckwheat’s raised bed cover crop merits, let’s talk technical and learn how and when to grow it.  Buckwheat seed is easily found and can be bought in nearly any quantity.  I bought a one-pound bag online from Johnny’s Selected Seeds for my raised beds, but you can also purchase larger sizes up to 50 lb bags if you have a large area to cover.  Buckwheat seed germinates quickly as soon as nights are warmer than 50 degrees F and can be cropped continuously until frost strikes in the fall.   A general seeding rate of 2 or 3 lbs/1000 square feet (enough to cover about thirty 4’x8’ raised beds, it goes a long way!) will generate a thick cover.  Simply extrapolate this out to 50-80 lbs/acre for larger garden sites.  I scattered seeds over the top of my beds at the above rate and covered lightly with garden soil and obtained good results.  Unlike other cover crops (I’m looking at you Crimson Clover) Buckwheat is very tolerant of imperfect planting depths.  If you plant a little deep, it will generally still come up.  A bonus, no additional fertilizer is required to grow a Buckwheat cover in the garden, the leftover nutrients from the previous vegetable crop will normally be sufficient!

Buckwheat “mulch” after termination. Photo courtesy of Daniel Leonard, UF/IFAS Calhoun County Extension.

Past the usual cover crop benefits, the thing that makes Buckwheat stand out among its peers as a garden cover is its extremely rapid growth and short life span.  From seed sowing to termination, a Buckwheat cover is only in the garden for 4-8 weeks, depending on what you want to use it for.  After four weeks, you’ll have a quick, thick cover and subsequent mulch once terminated.  After eight weeks or so, you’ll realize the plant’s full flowering and beneficial/pollinator insect attracting potential.  This lends great flexibility as to when it can be planted.  Have your winter greens quit on you but you’re not quite ready to set out tomatoes?  Plant a quick Buckwheat cover!  Yellow squash wilting in the heat of summer but it’s not quite time yet for the fall garden?  Plant a Buckwheat cover and tend it the rest of the summer!  Followed spacing guidelines and only planted three Eggplant transplants in a 4’x8’ raised bed and have lots of open space for weeds to grow until the Eggplant fills in?  Plant a Buckwheat cover and terminate before it begins to compete with the Eggplant!

If a soil building, weed suppressing, beneficial insect attracting, gorgeous cover crop for those fallow garden spots sounds like something you might like, plant a little Buckwheat!  For more information on Buckwheat, cover crops, or any other gardening topic, contact your local UF/IFAS County Extension Office.  Happy Gardening!

Daniel J. Leonard
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