The 10-20-30 Rule: attracting beneficial insects (et al) to your organic garden

Biodiversity in the organic garden used to seem like a complicated thing to plan for, but not since I learned the 10-20-30 rule for eco*logically attracting beneficials to my edible gardens.

  1. Allow no more than 10 percent (1 in 10) of the garden to be any one species (and aaalllll those roses are often the same species, same with all those tomatoes).
  2. Allow no more than 20 percent (1 in 5) of the garden to be any one genus (and aaalllll those squashes are Cucurbita, even they are mixed between maxima, mixta, moschata, and pepo.)
  3. Allow no more than 30 percent (1 in 3) of the garden to be any one family.  Cabbage, cauliflower, broccoli, collards, kale, turnips, radish, mustard…. all cabbage family: Brassicaceae. (brah-sik-uh-ay-cee-ee)  Tomatoes, potatoes, eggplants, peppers, datura, and even tobacco are all nightshades, a.k.a. Solanaceae (so-lo-nay-cee-ee).  (ps-This is why smokers must wash their hands before entering a vegetable garden- tobacco mosaic will transfer!)
dill herb flower dillseed seed

Dill flowers create habitat for beneficial insects. (Rain barrel behind).

Following this logic, and seeking to attract as many beneficials to the garden as possible, I’ve begun adding flowers into my vegetable and herb gardens.  I currently lack the gleeful abandon that Kevin Songer has (and he swears he gets great results), I’m more than happy to create both borders (lines) and checkerboards (patches) of an array of biennial and perennial herbs and flowers.

Probably the prettiest garden bed I’ve ever done was a simple mix of rainbow chard (green leaves with colorful stems) and bull’s blood beets (dark purple leaves) surrounded by Alaska nasturtiums (red flowers, variegated leaves). All of those leaves are edible, plus the flowers of the nasturtium and the beets themselves.  (A word of warning: despite reports to the contrary, I’ve yet to see nasturtium leaves hold up to cooking.  Just stick’em on a sandwich or make a pesto.)

Black-eyed Susans Rudbeckia hirta

Black-eyed Susans keep pollinators entertained.

Other flowers I’ve included in my borders or in intermingled beds include: dill, parsley, oregano, rosemary, lavender, lemon balm, lovage, thyme, sage, bee balm, echinacea, daisies, black-eyed susans (and other rudbeckia), yarrow, and mullein.  Those are all pretty “normal” organic garden plants.  I’d like to start including more of the local natives into this mix, things I’m finding to be very pretty out while I’m out on walks: butterflyweed and euphorbia and what-not.

In this next year’s garden, I plan to go a step further and pair some flowers I’m willing to treat as annuals in with annual vegetables that seem a compatible, both botanically and aesthetically. I’m putting cosmos into my pepper patch and my favorite short red dahlia in with the eggplants. If I get really nutty, I may even put a 6 pack o’ petunias in with the squashes.  Ha!  What’ll the neighbors think!

adding flowers will attract beneficial insects and birds

Puddin' (very old and wearing many bells) loves watching the birds that visit our organic vegetable garden.

The gist of it is this: biodiversity in your garden ought to be fun.  Adding more flowers will add beauty and a very serene joy.  Attracting more insects of all sorts will attract more birds.  My goal is a tiny piece of whatever you want to call it: Eden, Shangri-la, Arcadia, Utopia, Nirvana… I’ll keep you updated.

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4 Responses to The 10-20-30 Rule: attracting beneficial insects (et al) to your organic garden

  1. Love it! Pollinators love the complex buffet! Let me know how it works! :) Kevin

  2. Oh my goodness! Incredible article dude! Many thanks,
    However I am having troubles with your RSS. I don’t understand why I cannot join it.
    Is there anyone else getting the same RSS problems?
    Anyone that knows the solution can you kindly respond? Thanks!!

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