Get into permaculture and within no time an entire field of jargon is sprouting up around you, and while it can be exciting to have all these new ideas to ponder and play with, it can also be a bit intimidating…bewildering…intense. Well, at some point or another we’ve all felt that way, but even so, it’s time to talk about one of those mysterious terms: intercropping.
In order to have an appropriate discussion, however, we’ll need to define and separate a few ideas so that all readers are on the same page. For those of us who’ve studied permaculture, the point of intercropping will be fairly obvious, if not completely familiar and/or recognized under a different name. Nevertheless, we will ultimately examine why we might want to try it, as well as some of the more commonplace considerations for intercropping.
And, I suppose that’s enough for us to get started.
What It Is
Intercropping is growing two or more crops together at the same time in the same space in a beneficial manner. Row intercropping is working this arrangement with at least one of the components being planted in rows. Strip intercropping is a more industrialized version with rows of individual crops big enough to be harvested with machinery. Mixed intercropping is more like what we imagine as a guild, in which plants are bunched together more naturally but in purposeful ways. Relay intercropping is when the plants being intercropped are timed so that they are planted as the others are between flowering and harvesting.
These are the basic four methods commonly employed. Sometimes they involve annual grains and vegetables, such as the mixed intercropping classic of corn, beans and squash. Sometimes there are perennial species with annual crops grown amongst them, say perennial garlic and basil with annual tomatoes. Perennials also work well with other perennials. In parts of the tropics, bananas, papayas, coffee, vanilla and cacao make a crackerjack intercropping team. Sometimes these work in organized rows, other times in other patterns, but the main thought is to make thoughtful combinations.
In essence, these are all forms of companion planting, in which one plant provides some useful component for another. The technique can be small in scale, something seen in a home garden, but strip cropping is also becoming more common for progressive industrial models.
What It Isn’t
However, what it isn’t—at least not if done well—is a careless congregation of different plants. Some things just don’t belong together. For example, tomatoes, eggplants and potatoes are all from the nightshade family, so they don’t work well for intercropping. For one, they use similar nutrients. As well, they attract similar pests and are susceptible to similar diseases. Intercropping with things from the same family is asking for nutrient depletion while promoting troublesome insects and illnesses through a lesser version of, though not far off from, mono-cropping.
Beyond not using the same family, there are some other considerations. With mixed intercropping, it’s imperative to consider root structures, such that plants don’t crowd each other out beneath the surface, as well as above groundsizes, which could interfere with the specific sun requirements of other plants. Or, considering strip intercropping, it would be very important to practice sound crop rotation within the rows in order to avoid dormant pests and diseases in the next crop, as well as—again—specific nutrient depletion in soil.
Note: Intercropping and crop rotation are not the same thing, as intercropping requires that different types of plants are grown in the same space at the same time while crop rotation is the concept of growing different types of plants in the same space at different times. In crop rotation, the plants don’t necessarily need to be good companions in the same way.
Why We Do It
There are many reasons for why we would want to intercrop. It can help suppress weeds, especially if we time-sequence our planting such that a cultivated choice is always occupying the space. It can help us combat pests and diseases, especially those which are soil-borne and can transfer from one year to the next. It improves the soil structure, alternating root types and adding different forms of organic matter to the surface, all of which helps to create rich, crumbly earth. It also keeps fertility levels balanced by using different plants with different needs, as well as some with valuable soil inputs, such as with the ever-popular nitrogen-fixing legumes.
And, of course, listing all the benefits of intercropping elaborates the pitfalls it helps us avoid. We are controlling weeds, eliminating pests, thwarting diseases, conditioning the soil, and creating diverse—thus, more secure—abundance through intercropping. But, do the opposite and cultivate in monocultures, and it will encourage weeds, invite pests, breed disease, damage the soil, and rely on one fickle crop for our livelihood. The improved soil structure prevents erosion issues. The crops flowering at different times keeps beneficial insects around instead of seeing them off after one, and only one, type of plant matures. And, the non-competitive nature of growing different plants in the same space provides larger overall yields rather than a harvest of one crop.
We intercrop because to do differently—seemingly so—is completely counterintuitive to what serious and sustainable food cultivators would want to do. The modern-day monoculture standard is one completely reliant on petroleum, agrochemicals, endless water supplies, and land expansion. It leaves a wasteland in its wake.
How to Begin
This is much the same as building a guild, though row, strip, and relay intercropping are often also used for large quantity grain, vegetables and legume crops, which don’t necessarily conveniently fit into a food forest. For those interested in introducing or reimagining intercropping within their own gardens, here are some things to consider as you get started.
Feature Photo: Strip Intercropping (Courtesy of Oregon State University)