“Companion Planting” in the School Garden

The essential properties of an organism, or living system, are properties of the whole, which none of the parts have. They arise from the interactions and relationships among the parts

– A quote from “The Web of Life” by Fritjof Capra, Systems Theorist, Co-Founder of the Center for Ecoliteracy

In school gardens, “companion planting” is an excellent way for students to learn about relationships. This simple gardening technique of planting different species in the same garden bed reinforces a growing understanding of the interconnectedness of all living and non-living things – the backbone of comprehending ecology and systems theory.

Calendula, Kale, "Rocket" Arugula

Calendula, “Red Russian” Kale and “Rocket” Arugula growing in a San Francisco Elementary School Garden

Companion planting is also an excellent way to grow food more productively in small spaces! It does, however, take some practice to do it successfully.

So, what are the considerations you need to make before “companion planting” two or more species close together in a vegetable bed?

1.) Is there a pest that likes one crop, which another can deter if planted close by?

An example in the Fall garden is planting garlic, leeks or onions around garden vegetables that are vulnerable to gophers (artichokes, kale, celery, broccoli – gophers will eat just about anything actually!). As gophers dig through the soil, they find the garlic, leek, and onion odors unfavorable and look for another place to burrow, leaving your beloved vegetables alone!

Celery, Leeks, Kale

Celery, Leeks and “Toscano” Kale growing at Grimmway Academy, Arvin, CA

2.) Is there another positive attribute that one plant has that can help others?

A good Fall example here is planting legumes – Fava beans, peas, vetch, clover etc. near plants that like Nitrogen (“N”). In an orchard, an understory of clover is a perfect companion to fruit trees because legumes “fix” Nitrogen in the soil with the help of beneficial soil microorganisms, making the most important element in plant growth available in abundance to your fruit trees. Clover seeds can be broadcast liberally around your orchard this time of year and will form a lush blanket once the rains come (fingers crossed!). Legumes are also good in a diverse cover crop, which is grown in rotation with other crops to improve fertility.

Next Spring, try planting pole beans next to “heavy feeders” like corn and squash, employing the thousands of years – old method of “Three Sisters” companion planting. The corn is planted first, then the beans 1-2 weeks later, and then the squash, once the beans have germinated. The corn provides a trellis for the beans to vine up, the beans fix Nitrogen for its two other sisters, and the squash shades the roots of all three species during long, hot summer days.

The Three Sisters

The Three Sisters – Corn, Beans and Squash

3.) Time the planting of each crop as accurately as possible.

Each crop has a different requirement of days from planting to harvest (see the back of your seed packet for some clues, though this varies significantly based on season and climate zone). When selecting companion plants, choose two to three species that you know have similar life cycle lengths, or stagger their planting so that the faster crops comes out as the slower ones mature and fill in the bed.

We like to do this with lettuce and radishes this time of year.  We transplant lettuces into a nicely cultivated bed, amended with some good organic (ideally school-grown) compost. In general, rows of lettuce are spaced about 6-8 inches apart and there are 6-8 inch spaces between plants. Then, we draw a line in the soil in between the lettuce rows, sow radish seeds about 1 inch apart from one another, and cover them with 1/2 inch of soil (‘Easter Egg’ and ‘French Breakfast’ radishes are our favorite varieties). The radishes germinate quickly and reach maturity in 5-6 weeks. We harvest the radishes just as the lettuces are beginning to claim the space in between the rows. The lettuce uses the entire bed for the remainder of it’s cycle, fully ripe heads mature 2-3 weeks after the radish harvest.

Lettuce and Radishes

Lettuce and Radishes growing in a San Francisco High School Garden

Happy companion planting everyone!

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