How and Why to Rotate Your Annual Crops

Sure enough the bulk of us permies are working to establish perennial sources of food, cultivating food forests for high yields with low inputs. Nevertheless, annual food crops are often what our kitchen gardens are chiefly comprised of. It’s no big shock, really, as that has been what most of us have grown up eating, enjoy the flavor of, and thus want to grow.

No doubt, we should be cultivating perennials as a priority, but we needn’t pretend as the annuals are wholly awful when we know for sure that they are awfully delicious. If we admit, despite our better judgment, that we will be growing them, then we can begin working them efficiently into our systems, such as with intercropping.

Grown on a large scale long term, in addition to companion planting and successional planting, annuals will likely need a proper crop rotation, so it behooves us all to have some awareness as to the basics of it. In the simplest of terms, crop rotation boils down to not planting the same crop in the same soil year after year but cycling them from bed to bed, ideally in a meaningful way.

Why Do We Rotate Crops?

Urban Harvest Tour – Rotation Beds (Courtesy of Jonti Bolles)
Urban Harvest Tour – Rotation Beds (Courtesy of Jonti Bolles)

Nowadays, with farming being so specialized, we see standard monocultures grown by corporations that focus on one food product, often corn, wheat, or soy. This, of course, has become widely known as detrimental to our planet (and health) in many different ways, notably in that the system just wrecks soil, making it a completely reliant on outside—usually chemical—inputs. (Incidentally, it’s done something similar to the humans eating it, hence all the prescription meds.)

High octane annual gardens, which don’t act as self-reliant ecosystems, require a lot more nutrition from the earth. This is one of the reason permaculture so promotes perennial food systems: They support themselves and strengthen over time. Annual systems, however, will require more consistent and constant attention, including seed harvesting, seasonal replanting, and—we are getting there slowly—soil amending.

Rotating crops is one way to minimize the amount the negative effects on the earth in which we are growing, as well as provide bountiful, nutritionally rich harvests from healthy plants. Crop rotation helps us combat diseases, avoid pest problems, and maintain well-balanced soils. Because different crops are susceptible to different pathogens, appetizing to different bugs, and reliant on different diets, a thoughtful rotation can help us monitor and regulate these things, having our gardens function beyond just immediate food production.

How Do We Rotate Crops?

Hippy in the Garden (Courtesy of Irene Kightley)
Hippy in the Garden (Courtesy of Irene Kightley)

The first step to conceiving a good crop rotation is being aware of the plants we are dealing with, specifically noting what family of plants each item we are growing belongs to. Here’s a link to a more comprehensive reference, and below is a quick and common collection for us to consider now for a basic four-year rotation plan.

• Nightshades (Solanaceae): potatoes, tomatoes, peppers, eggplant

• Cruciferous (Brassicaceae): kale, cabbages, broccoli, cauliflower, mustard

• Legumes (Fabaceae): green beans, garden peas, snow peas, kidney beans, lentils

• Roots (Amaryllidaceae): onions, leeks, garlic, (Apiaceae): beets, parsnips, celery, carrots and (Chenapodiaceae): beets

Each of these assemblies of plants have different characteristics and needs. For example, leafy crops like those in the cruciferous family tend to be hungry for easy-to-reach nutrients that, despite the shallow roots of the plants, provide for the production of big leaves. Legumes are well respected for the ability to take nitrogen (a major key to fertility) from the air and “fix” it into the soil. Root vegetables are very good at finding their own sources of minerals, burrowing down as need be. Nightshades, particularly tomatoes and potatoes, struggle with blight and other diseases, so rotating them helps to provide protection from this.

With regards to these four groups, people generally try to start with a nitrogen-fixing legume, moving onto the hungry brassicas that’ll enjoy that fertility, onto nightshades to soak the last bits of readily available nutrients, and finally the industrious root crops, which are good at scavenging what they need from the soil. Then, the cycle starts over again. As the garden gets more complex, with other families, such as Cucurbitaceae (cucumbers, melons, squashes) and Compositae (lettuce, sunflowers, yacon), the rotation plan can extend through more seasons.

Adding Perennial Elements & Other Tips to Consider

Picking Berries (Courtesy of Tammy Strobel)
Picking Berries (Courtesy of Tammy Strobel)

Just because a garden is predominately constructed with annual crops in mind doesn’t mean that we shouldn’t include perennial—permanent—elements to it. Though these plants won’t necessarily feature in our rotation plans, they can provide additional harvests, space efficiency, and valuable services to our annual gardens. Also, sometimes it’s wise to simply allow beds to rest or, even better, grow green manures to be cut down and fed straight back into the soil.

Here are some thoughts on perennial plants to include in the annual rotation beds.

• Culinary Herbs: Most culinary herbs are also aromatic plants that help with pest control and often attract beneficial insects like butterflies and bees to the garden. Having herbs there—at the end of rows, perhaps planted every couple of meters, will help to insure that pest avoid the spot and pollinators stay near it. Options include mint, rosemary, sage, oregano, tarragon, thyme, chives…

• Berry Bushes: Berry bushes are make for great hedges (useful animal habitats), which provide natural and highly productive fencing for the kitchen garden. The berry crop that occurs on the inner garden side of the bush could be for harvesting, and the outer crops could go to wildlife, which could distract them from the annuals.

• Perennial Vegetables: Some vegetables are just perennial, and they are great to include as another permanent element in annual garden patches. They add to the harvest, keep the garden up and running during resting time, provide biomass, and generally don’t interfere much with annual plants. Rhubarb, asparagus, Jerusalem artichoke, and French sorrel are all beloved perennial veggies that can add another element of biodiversity to the run-of-the-mill rotation.

• Small Fruit Trees: Placed sparsely amongst the garden, small fruit trees can help provide particular microclimates, providing a bit of shade here and there, as well as utilize vertical space that annual crops don’t tend to reach. Plus, they are yet another way to attract beneficial animals into the area for pollination, fertilization, and pest control.

Green manures can also play a vital role in keeping the soil constantly covered and fertile.

• Dynamic Accumulators: Many growers like to plant dynamic accumulators with deep tap roots and lots of biomass as borders within, amongst and between beds. These plants pull nutrients from beneath the reach of most annual vegetables, which tend to have shallow root systems, and deposit them atop the soil through leafy matter. Comfrey, borage, and dandelions are all good accumulators with edible and/or medicinal functions to boot.

• Green Manures: Nitrogen-fixing legumes, namely the beans and peas, are great crops but throwing a green manure ground cover into the rotation is another great way to keep the soil fertile, as well as add organic material to it and protect the soil life during periods of rest (from crop production). Nitrogen-fixers like red clover, alfalfa, and vetch are all edible, but the point here is to put the bulk of them right back to the soil as nutrient-rich mulches, providing nitrogen blasts beneath and atop the surface.

The complexity, as with anything, can become more and more intense, but with most ideas in permaculture, a general understanding of how such systems work is a great starting point for exploration and experimentation. This technique is nothing new but rather something that has largely—at least for a while there—gotten overlooked in industrial agriculture. We still have to be thoughtful about climate and bed placement and all of the other things that go into a holistic system, but undoubtedly, this is one more component to intelligent design that can make plants multi-functional and our efforts more efficient.

Feature Photo: Veggies (Courtesy of Nicole Bratt)

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