Musical Garden Beds Make For Higher Yields
It’s a bit early for actual planting, but January is the traditional time to work on our paper gardens. With the veggie beds emptied, replenished with mature compost, and mulched to protect them from the winter rains, we can dream into crops for the coming year. Naturally, we begin with wish lists, supplementing our must-have old favorites with new and tempting plants, edible and ornamental. Then we sadly hone the list to comply with the reality of the allotted space. There’s never enough room for everything, and in vegetable plots, it’s important to remember that each plant family has its own nutritional needs and demands, so practicing crop rotation helps to keep your soil in good heart.
Indeed, numerous studies show that continually planting the same crops in the same place will steadily reduce both plant health and harvest. This crop-related nutritional drain can even hold true for same-family plants. Recent research projects at Cornell found that beans yielded twice as much when planted in a bed that had held corn than when they were planted where peas had last grown. Several studies found that growing the same kinds of crops in the same patch of soil year after year can markedly increase the likelihood of crop-specific diseases. Instead of using pesticides to battle those diseases, many organic growers prefer to use crop rotation to keep soil and plants healthy.
Keeping track of crops and making sure they alternate frequently may sound daunting, but it isn’t truly all that complicated. Even in small gardens with raised beds, it’s usually possible to work out a three- or four-year rotation. In simple terms, this involves recognizing the eight major food crop families and recording where you grow clan members each season. This requires some kind of charting so you can keep track easily. Garden bed charts don’t have to be art works but they do need to clearly show where you grew what. Date each chart and hang on to it for at least three years. Why? It will help you avoid situations like following tomato crops with peppers or potatoes, all nightshade cousins that are heavy users of a lot of the same nutrients.
To make it super easy, draw a basic layout of your garden, showing each bed. (Use graph paper if you really can’t draw.) Make a bunch of copies, then record each season’s plantings. When you change out one crop for another, don’t erase the earlier ones. Instead, number them so you remember the order in which they grew. That way, you can flip through your 2016 charts before deciding where your 2017 crops will end up. If you can, create charts for recent years as well. In a few seasons, you’ll have a clear record to consult when planning and healthier crops to boot.
It’s also useful to know that some family cycles are particularly beneficial. For instance, both legumes and nightshades do particularly well when planted where sweet corn recently grew. Conversely, it’s less productive for squash family members to follow tomatoes and vice versa, probably because both need lots of calcium. (Our Northwestern soils tend to be calcium poor anyway, so both these crops will benefit when you spray the foliage with diluted skim milk. A 10% solution of 1 part skim milk powder mixed with water works well and won’t clog most sprayers.)
In any case, basic crop rotation is not hugely complex as long as we remember those eight main families. Nightshades are a big one, as mentioned above. The coles include cabbage, kale, broccoli, turnips, wasabi and Brussels sprouts and many leafy greens. Peas, beans, lentils and alfalfa are all nitrogen-fixing legumes, which can leave soil better than they found it. The squash family includes cucumbers and melons as well as zucchini and pumpkins. The beet family includes spinach, quinoa and chard, while the onion clan runs from garlic, leeks, and shallots to chives. Celery, parsnips, and parsley are carrot cousins, as are dill and fennel, both of which do best planted alone. Lettuce, artichokes, chamomile, chicory, and tuberous yacon belong to the sunflower crew. Corn is actually a kind of grass, kin to oats, barley, wheat, and rye.
Charting An Ever Changing Course
If it’s hard to recall offhand, it might help to make a chart of these families, perhaps using color keys to help you remember. One classic rotation cycle runs pretty much like this: tomatoes; peas or beans; cabbage family; carrot family; sweet corn or grain; potatoes; squash family; beet family. When you look at the garden plan this way, it starts to makes sense; alternate root crops with leafy greens, or gross feeders like squash with nitrogen fixers like peas. By keeping your charts for several years, you avoid repeating sequences too soon. And again, don’t erase an entry when a summer crop follows early ones; you want as complete a record as possible, so make the bed spaces on your drawing large enough to indicate as many crops per year as needed.
Always replenish the soil between crops, and use cover crops over the winter or whenever a bed will lie fallow for a few months. This is especially important in small spaces where there really aren’t many good choices for certain crops and some repetition is unavoidable. Buckwheat (rhubarb family) is a fast growing soil builder, as is winter rye. Fava beans and field peas are excellent conditioners that add their captured nitrogen to the soil. Annual clovers are good for soil but can be hard to get rid of, while garden cover blends offer regionally appropriate mixtures, often combining crimson clover, vetch, triticale, rye, and field peas. Happy New Year!