Crop Rotation: A Simple 3-Year Plan
Growing tomatoes in the same bed year after year is the fastest route to tired soil and thriving diseases. Crop rotation — moving plant families around the garden so none returns to the same spot more than one year in three — is the oldest free fertiliser and pesticide in gardening. Here is a simple plan that fits on an index card.
Crop rotation means never growing the same vegetable family in the same soil more than one year in three. Sort crops into four groups — legumes, brassicas, roots & onions, and fruiting crops — and move each group one plot forward every year, so every group returns to its starting plot only after three years away. The plan below fits four plots (split a bed if you have three), starves out soil-borne diseases, and lets nitrogen-fixing legumes feed the hungriest crops.
Why rotation matters: the 3-year rule
Three enemies build up when one family stays put. Soil-borne diseases — fusarium wilt in tomatoes, clubroot in brassicas, white rot in onions — overwinter in the soil and strike harder each year. Pests that feed on one family, from carrot fly to cabbage root fly, learn where dinner is. And nutrients deplete one-sidedly, because each family draws most heavily on the same elements.
The 3-year rule answers all three: a family should not return to the same soil until three full growing seasons have passed. (Clubroot can persist even longer — up to 7 years in bad cases — which is why brassicas get extra caution and lime.)
Rotation also manages fertility for free. Legumes — peas and beans — fix nitrogen from the air through nodules on their roots, leaving richer soil for whatever hungry crop follows them.
The four crop groups
Nearly every vegetable slots into one of these groups. Learn the groups and the plan runs itself:
| Group | Plant family | Crops | Appetite |
|---|---|---|---|
| Legumes | Pea family | Peas, broad beans, dwarf and climbing beans | Light — fixes its own nitrogen |
| Brassicas | Cabbage family | Cabbage, broccoli, cauliflower, kale, radish, turnips | Heavy |
| Roots & onions | Carrot and onion families | Carrots, parsnips, beetroot, onions, garlic, leeks | Light — hates fresh manure |
| Fruiting | Nightshade, cucurbit and grass families | Tomatoes, potatoes, peppers, eggplant, courgettes, squash, cucumbers, sweetcorn | Heaviest |
The 3-year rotation grid
Four plots, three years, one rule: each group moves one plot forward every spring.
| Plot 1 | Plot 2 | Plot 3 | Plot 4 | |
|---|---|---|---|---|
| Year 1 | Legumes | Brassicas | Roots & onions | Fruiting |
| Year 2 | Brassicas | Roots & onions | Fruiting | Legumes |
| Year 3 | Roots & onions | Fruiting | Legumes | Brassicas |
| Year 4 | = Year 1 — the cycle repeats | |||
Follow any single group across the row: legumes sit in Plot 1 in Year 1 and do not return until Year 4 — three full years away. Notice the elegant bit: brassicas follow legumes every year, cashing in the nitrogen the legumes fixed.
Map the maths of your beds
The Calculators hub holds every GardenMathLab tool — size new beds for your rotation, balance the compost that feeds each group, and schedule watering through the season.
Drawing your own plan
- Sketch your plots and number them 1–4. Only have three beds? Split the largest bed in half lengthways — each half counts as a plot.
- Write this year’s groups into the grid above, starting wherever suits what is already planted.
- Pin the plan in the shed. Future you — ordering seeds in January — will be grateful.
- Place overwintering crops carefully. Garlic planted in October belongs to the roots & onions group, so plant it in whichever plot holds that group next spring.
Feeding each group
Rotation and feeding work as a pair. Each group wants different treatment:
| Group | At planting | During the season |
|---|---|---|
| Legumes | Nothing — or a light dusting of compost | Leave roots in the ground after harvest; the nodules release nitrogen as they decay |
| Brassicas | 1–2 in of compost; lime if the soil is acidic (clubroot fades above pH 7) | Net against pigeons; water generously — they are thirsty |
| Roots & onions | Last year’s compost only — fresh manure forks carrots | Thin ruthlessly; weed little and often |
| Fruiting | Rich compost plus a balanced fertiliser | Mulch, and feed tomatoes every 2 weeks once fruit sets |
Rotation in small gardens and containers
- Two beds? Split each in half and rotate the halves — four plots from two beds.
- One bed? Divide it into quarters and rotate the quarters.
- Containers? The soil is the plot: either replace the mix every 2–3 years or rotate crop families between pots — and never follow tomatoes with potatoes in the same pot.
- The minimum viable rotation: never plant the same family in the same soil two years running. Even this halves disease pressure.
Frequently asked questions
Do I need to rotate in raised beds with brand-new mix?
Less urgently — fresh mix starts disease-free — but begin rotating from year one anyway. By year three the pathogens will have arrived, and a plan already in motion beats one started in crisis.
What about perennial vegetables?
Rhubarb, asparagus, artichokes and perennial herbs stay put permanently — they are outside the rotation. Plan your annual plots around them.
Can tomatoes follow potatoes?
Never — both are nightshades sharing blight and wilt diseases. The tomato-potato pairing is the single most important one to avoid, which is why both sit in the fruiting group.
How do I keep track of the plan?
A sketch in a garden journal, a phone photo of a labelled plan each spring, or chalk labels on the bed frames. The system only works if you can read last year’s notes.
Does companion planting replace rotation?
No. Companion planting helps within a season; rotation protects across years. The two stack — use both.
Related guides
Succession Planting: Keep Harvests Coming All Season
Rotate plant families between successions within the year, not just between years.
How to Compost at Home for Beginners
Brew the compost that feeds each rotation group — greens, browns and the 30:1 ratio.
Easiest Vegetables to Grow for Beginners
Choose one reliable crop for each group of the plan and start rotating this spring.
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