Crop rotation is a planting practice used by farmers and home gardeners to rotate crops on the same plot. It requires planning and detailed record-keeping every year of what you plant in your garden, but it is time well spent that will pay off at harvest time.
Crop rotation is crucial for soil health, nutrient balance in the soil, and pest and disease control.
Why Crop Rotation is Important
The nutrients that each vegetable and fruit take out of the soil are different both in terms of the type of nutrient and the amount. Leafy vegetables, for example, require more nitrogen, whereas root vegetables, such as carrots, need more phosphorus. Crops belonging to the same plant family are similar in their nutrient requirements.
As a result, what you grow in a certain location has an impact on soil fertility. Planting the same crop in the same location year after year depletes the soil nutrients and causes a nutrient imbalance. This then leads to poor harvests. Rotating crops, on the other hand, allows the soil to replenish.
Soil fertility, however, is only one reason for crop rotation. Crops belonging to the same plant family are prone to similar pests and diseases. Many plant pathogens and insect pests are soil-borne. They survive in the soil even during the winter, then multiply in the soil the next year.
If you plant the same crop in the same soil year after year, the pests and diseases will have an easy host to attack. Planting different crops breaks that cycle because you take away their breeding ground or food source.
If you have the space, dedicating a whole garden bed to a single plant family facilitates crop rotation.
How to Practice Crop Rotation
You can create your own crop rotation planner by keeping track of what you plant every year. There are even garden planning apps available.
The first step in crop rotation planning is to make a list of the crops that you want to grow in your garden. Divide them into the plant families to which they belong (there is a handy reference list included below). Then make a map of your garden or vegetable beds, to scale, and mark the allocated space for each plant family. Hold onto your map so you’ll know what you planted where when you plan next year’s garden.
A common recommendation is to wait three or four years before growing crops from the same plant family in the same location. However, that is just not always realistic in a small garden, or if you grow a wide variety of crops from different plant families.
Not planting crops from the same plant family in the same location in two consecutive years is, at least, a good alternative in small spaces.
What’s The Order of Crop Rotation
A systematic approach to crop rotation is to move each plant family group one spot clockwise every year. That might not always be practical because there are other factors to consider as well. For example, you don’t want the tall corn to cast shade on peppers which need maximum sunlight.
To determine which crop should go where, it also helps to familiarize yourself with the nutrient requirements of each vegetable. Beans and peas fix nitrogen in the soil, therefore vegetables such as kale, which prefer nitrogen-rich soil, are a good crop to plant in that location the year after. Root vegetables on the other hand are not a good succession crop for that location because high nitrogen levels will make them grow lots of foliage instead of what you are after—large, fleshy roots.
Companion planting also helps in crop rotation planning to determine which plants make good or bad neighbors.
This table list common annual vegetables, fruits, and herbs with their plant families. Perennial crops such as fruit trees, berries, rhubarb, and asparagus, as well as perennial herbs are not included in this list, as they are not replanted every year.
|Aizoaceae (Fig-marigold family)||New Zealand spinach|
|Asteraceae (Aster family)||Artichoke
|Basellaceae (Madeira-vine family)||Malabar spinach|
|Brassicaceae (Crucifers, cabbage family)||Arugula
|Chenopodiaceae (Goosefoot family)||Beets
|Convolvulaceae (Bindweed or morning glory family)||Sweet potato|
|Cucurbitaceae (Cucurbits, gourd family)||Cucamelon
|Fabaceae (Legume, pea, or bean family)||Bean
|Lamiaceae (Mint family)||Basil|
|Liliaceae (Lily family)||Garlic
|Portulacaceae (Purslane family)||Purslane|
|Solanaceae (Nightshade family)||Eggplant
|Valerianaceae (Valerian family)||Corn salad (lamb's lettuce, mâche)|