Crop rotation is a little like contradancing. You start at one end of the hall (or field) with a group of acquaintances, and end up at the other side surrounded by a completely different set of neighbors. And, it's ok if you aren't entirely sure how you got there.
The concept of rotation is very simple: it is a good idea to change the location within the garden where you plant your vegetables from year to year. The main goals are to disrupt disease and pest problems, and to match crops with the nutrients available. This year's cucumbers in the bed farthest from the house might be followed by a sowing of lettuce next year; the cucumbers will then be planted in the bed next to the house. And so on. However, the rationale for specific crop rotations is very complicated.
The University of Tennessee Extension has a concise handout on rotation theory that lists the following rotation strategies:
- Rotate by plant family
- Rotate by plant part harvested
- Rotate by plant compatibility
- Rotate by nutrient requirements
- Rotate by rooting depth and type
- Include legumes and cover crops
As a non-expert grower, my guess is that some considerations are more crucial than others. Members of the same plant family may be susceptible to the same soil-borne diseases so, for example, I don't grow tomatoes and potatoes (family: Solonaceae) in the same location in consecutive years. Sorting vegetables by part harvested – root, leaf, or fruit (seed) – is easily done, and helps to shape multi-year planning. But when plant compatibility clashes with plant rooting depth -what then?
Farmers who use rotation are generally limited by the small variety of crops they grow, but gardeners who grow a little of everything have an opportunity to map out an almost infinite number of rotation schemes. In one of the most dog-eared books on my shelf, Step by Step Organic Vegetable Gardening(1992), Shepherd Ogden takes a garden with four beds, divides each bed in half, and creates a 4 year rotation scheme that involves 8 different crops. He includes fall and spring plantings, and throws in a cover crop for good measure. And yet, this plan would not be difficult to implement as long as you keep reasonable records.
Do you rotate your vegetables, and if so, what is your method?