Quick & Easy Annual Insectary Rows

A thriving population of parasitic wasps, beetles, and other beneficial insects are the lifeblood of biological control systems on any organic farm. Providing an adequate food source for these “beneficials” ensures their presence in your fields and increases their egg laying abilities. Perennial hedgerows hold a valuable place in any farmscape for inviting these populations, but they do require a bit of an investment - long term planning, purchasing plant starts, and time to install. In addition to perennial hedgerows, you can recruit beneficial insects to the farm with annual insectary rows that require minimal time commitment and are cost effective.

Although not directly a “cash crop,” committing even a few of your rows to flowers throughout the course of the season is bound to ease the burden of inevitable pest management. It’s ideal to sync up the flower’s bloom time with the life cycle of surrounding crops, as flowers will provide the greatest advantage when they reach full maturity. If you have a diversified planting plan, you can dedicate a bed or row specifically for flowers, just as you would with cash crops. On the flip side, you can also simply keep seed on hand to fill in gaps that might result from running out of transplants. Liz Milazzo, formerly at CASFS as Field Manager and now at Costanoa Commons Farm in Santa Cruz, has been incorporating insectary rows in her crop plan for years. She points out that, “edge beds are often lower in fertility, which usually doesn’t matter with insectary crops” making edges a convenient planting location. Additionally, it provides you the freedom of holding onto the blooming plants a bit longer even if adjacent crops have finished and need discing.

Photo credit: Liz Milazzo

Knowing the growth habit of the species you select will help inform how you place and time plantings. It would be wise to avoid anything that grows too vigorously which results in either material too fibrous to mow or that sprawls onto neighboring beds. “Other problems I’ve encountered are the insectary trapping too much moisture in a foggy season, like a dense carpet of sweet alyssum” or “not realizing that the insectary would harbor an (unwanted) pest, such as the Lygus Bug on Phacelia or Bagrada bug on Alyssum” Liz shares. She also points out that it’s crucial for the insectary to be faster growing than the weed competition; specifically, “you need to see a strong line at germination to know that the insectary species will be able to adequately compete with the weeds.”

It’s really about quality not quantity. A UC study found that beneficial insects traveled as far as 250 feet from the insectary rows, proving that a little goes a long way. Liz’s favorite species for the California central coast are: Sweet Alyssum, Phacelia Tanectifolia, California Poppy, Clarkia Amoena, annual Buckwheat, Flax,and Cilantro (which she points out is “faster growing than other apiacea with reasonably priced seed.”) One of the reasons she prefers these selections is that they are tough species that can be planted densely without concern for overcrowding.

A larger list of insectary crops and the insects they host can be found here and a more detailed guide to selecting and designing insectary rows can be found here.

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