Crop rotation: how it works, with a 4-year plan
Moving crop families to a new bed each year starves soil pests and diseases and balances what the soil gives up. Step through it, then plan your own beds.
Why rotate at all?
Many garden troubles live in the soil and specialise in one plant family. Clubroot spores attack cabbage-family plants and can survive in soil for many years. Onion white rot waits for the next allium. Early blight overwinters on tomato debris. Grow the same family in the same place every year and these build up.
Families also feed differently. Peas and beans host Rhizobium bacteria that fix nitrogen from the air into root nodules; leafy brassicas are hungry for exactly that nitrogen; carrots and parsnips fork in freshly manured soil. A rotation lines these up so each crop gets the soil it likes.
The sequence behind most garden rotations is the one the explainer steps through: legumes → leaf & brassicas → fruiting crops → roots & alliums.
Crop rotation family chart
Find which rotation group each vegetable belongs to. Crops in the same family should move together.
| Family | Rotation group | Crops | Why it matters |
|---|---|---|---|
| Nightshades Solanaceae | Fruiting | Eggplant, Pepper, Potato, Tomato | Heavy feeders that share early blight, late blight and soil-borne wilts. |
| Brassicas Brassicaceae | Leaf & brassicas | Arugula, Broccoli, Cabbage, Cauliflower, Kale, Kohlrabi, Radish, Turnip | Hungry for nitrogen; clubroot spores persist in soil for years. |
| Legumes Fabaceae | Legumes | Bush bean, Pea, Pole bean | Host nitrogen-fixing Rhizobium bacteria in root nodules. |
| Cucurbits Cucurbitaceae | Fruiting | Cucumber, Melon, Winter squash, Zucchini | Sprawling, thirsty and prone to powdery mildew and cucumber beetles. |
| Roots & umbellifers Apiaceae / Amaranthaceae | Roots & alliums | Beet, Carrot, Parsnip | Light feeders; fresh manure makes carrots fork. |
| Alliums Amaryllidaceae | Roots & alliums | Chives, Garlic, Leek, Onion | Shallow-rooted; onion white rot survives in soil for many years. |
| Salad & greens Asteraceae / Amaranthaceae | Leaf & brassicas | Lettuce, Spinach, Swiss chard | Quick crops that fill gaps between slower ones. |
| Grasses Poaceae | Fruiting | Sweet corn | Wind-pollinated; plant in blocks, not single rows. |
Questions gardeners ask
How does crop rotation work?
You group vegetables by plant family and move each group to a different bed every year. Pests and diseases that attack one family lose their host, and crops with different nutrient needs follow each other so the soil isn't drained of the same thing year after year.
What is a 4-year crop rotation?
The classic sequence is legumes (peas, beans), then leafy crops and brassicas, then fruiting crops (tomatoes, squash, corn), then roots and alliums, then back to legumes. Each family returns to the same bed only every fourth year.
Is crop rotation worth it in a small garden?
Yes, though beds a few feet apart give less protection than fields, since soil and insects move. Rotation still helps against soil-borne diseases like clubroot and onion white rot, and it makes feeding the soil more deliberate.
Can I plant tomatoes in the same spot every year?
You can, but early blight and soil-borne wilts build up. If you must, choose resistant varieties, mulch to stop soil splashing onto leaves, and add plenty of compost. Rotating is easier.
Where do herbs and flowers go in a rotation?
Annual herbs and companion flowers can fill gaps in any bed. Perennials such as asparagus, strawberries and woody herbs get a permanent spot outside the rotation.