Crop rotation made simple: a four-bed plan
Moving crop families around your beds each season helps break pest and disease cycles and balances soil nutrients. A simple four-group plan, plus tips for small gardens.
4 min read 路 Patchmates
Crop rotation means not growing the same type of plant in the same spot season after season. It sounds technical, but at home it's just a simple habit: move things along.
Why rotate
- Pests and diseases. Many soil-borne problems build up when the same family grows in the same spot. Tomatoes, potatoes and their relatives share diseases, for example. Move them on and the problem has less to feed on.
- Nutrients. Different crops use soil differently. Leafy crops are hungry for nitrogen. Root crops prefer soil that isn't too rich, or they grow lots of leaf and hairy, forked roots. Legumes such as peas and beans work with soil bacteria to add some nitrogen back.
- Soil structure. Deep-rooted and shallow-rooted crops take turns working different layers of the soil.
Rotation won't fix everything, but combined with compost and mulch it keeps beds healthier over time.
The four groups
Most home gardens can use four simple groups.
| Group | Crops | What they like |
|---|---|---|
| Legumes | Peas, broad beans, climbing and dwarf beans | Average soil; they add some nitrogen |
| Brassicas and leafy greens | Broccoli, cabbage, cauliflower, kale, bok choy, lettuce, silverbeet | Rich soil, plenty of nitrogen |
| Fruiting crops | Tomato, capsicum, eggplant, chilli, potato, plus zucchini, pumpkin, cucumber and melons | Rich soil with lots of compost |
| Roots and alliums | Carrot, beetroot, parsnip, radish, onion, garlic, leek | Loose soil, not freshly manured |
Tomatoes, capsicums, eggplants, chillies and potatoes belong to one family (the solanaceae), and pumpkins, zucchini, cucumbers and melons belong to another (the cucurbits). Lumping them together in one group keeps things simple for a small garden, and both enjoy the same rich soil. If you have room, keep the two families apart too.
A simple four-bed plan
Number your beds 1 to 4. Each year, every group moves one bed along.
| Bed 1 | Bed 2 | Bed 3 | Bed 4 | |
|---|---|---|---|---|
| Year 1 | Legumes | Brassicas and leafy | Fruiting | Roots and alliums |
| Year 2 | Roots and alliums | Legumes | Brassicas and leafy | Fruiting |
| Year 3 | Fruiting | Roots and alliums | Legumes | Brassicas and leafy |
| Year 4 | Brassicas and leafy | Fruiting | Roots and alliums | Legumes |
After four years you're back where you started.
In Adelaide you can grow two main seasons a year, cool and warm. The order still works: in autumn a bed might have broad beans, and the next spring tomatoes go into the bed where the roots grew.
What comes after what
The usual order follows the soil.
- Legumes go first, into average soil, and leave a little extra nitrogen behind. Cut the plants at ground level when they finish and leave the roots in the soil.
- Brassicas and leafy greens follow, making good use of that nitrogen.
- Fruiting crops come next. Dig in plenty of compost or well-rotted manure before planting them.
- Roots and alliums follow, in soil that is still good but no longer freshly enriched. Fresh manure can make carrots fork.
Then back to legumes. A green manure crop, sown and dug in before it flowers, is a good way to refresh a tired bed between groups.
Small gardens: one or two beds
You don't need four beds to rotate. A few ideas:
- Rotate within the bed. Divide one bed into two to four sections and move each group along a section each season.
- Grow tomatoes in pots. Tomatoes and their relatives are the crops that benefit most from rotation. Growing them in large pots with fresh potting mix each year sidesteps the problem.
- Alternate seasons. If you only have one bed, avoid putting the same family back in the same spot two seasons running. For example, follow summer tomatoes with autumn peas or garlic, not more tomatoes.
- Leave the longest gap for the fussy ones. Try to give tomatoes, potatoes, capsicums and eggplants a few years before they return to the same spot.
- Feed the soil anyway. Even with perfect rotation, adding compost each season makes the biggest difference.
Keep notes
Rotation only works if you remember what grew where. A sketch in a notebook with the date and crops is enough. Patchmates keeps track for you: add your beds, log what you plant in each, and your planting history shows what grew there in previous seasons, so planning the next bed is quick.