Crop Rotation Planner
Lay out a four year rotation of plant families across your beds, so no family repeats too soon.
Most soil disease is a scheduling error. Blight, clubroot and onion white rot all build up when a family returns to the same soil too soon, and all fade when it stays away for three to four years. This planner takes the family in your first bed this year and rotates every bed through the families in a fixed, sensible order for four years, so the plan writes itself.
The order used here feeds the soil as well as resting it: legumes first (they leave nitrogen), then hungry brassicas to spend it, then fruiting crops, then the light-feeding roots and alliums. Within each family, the Companion Planting Tool arranges the neighbours.
How this rotation works
There are six family groups and four years on the table, which is the point: with more groups than years, no bed sees the same family twice inside the plan, and a six bed garden gets the full six year cycle by simply continuing. The order is the classic feeding sequence. Legumes leave the soil richer in nitrogen; brassicas, the hungriest feeders, follow and spend it; nightshades and cucurbits fruit in the middle; alliums and roots, light feeders with deep or shallow scavenging roots, close the cycle on leaner soil.
Assumptions:
- Beds are roughly equal. If one family always needs more room (potatoes, usually), that is fine: the rotation governs where, not how much, and a family can spill into a second bed in its year.
- Green manures and cover crops slot into any gap without breaking the plan; a legume cover even counts as the legume year if it grows a full season.
- The four year gap is the standard for clubroot and blight pressure; on land with known clubroot, brassicas want six years, which six beds give automatically.
Worked examples
1. Four beds, bed 1 in legumes this year. Bed 1 runs legumes, brassicas, nightshades, cucurbits. Bed 2 starts one step later at brassicas, and so on. Next spring every crop moves one bed along, and the notebook entry is one line per bed.
2. Three beds and a potato habit. Nightshades appear once in the cycle, so potatoes get one bed in three each year at most. Keen potato growers run a separate potato patch on its own longer rotation rather than distorting the main plan.
3. Six beds. Every family has a bed every year, and each bed cycles through all six families in six years: the deluxe version, worth it where clubroot or white rot has ever appeared.
Why families, not crops
Rotation is tracked by family because pests and diseases are family specialists. Potato blight takes tomatoes; clubroot takes every brassica from cabbage to radish; onion white rot takes the whole allium clan. Moving ‘the tomatoes’ achieves nothing if peppers and potatoes (same family) stay put. Grouping by family is also what makes the plan memorable: six groups are a system a gardener can hold in their head, while thirty crops are a spreadsheet nobody updates.
The second benefit is feeding. Families differ in appetite and in what they leave: legumes add nitrogen, brassicas strip it, roots break and scavenge deep. A rotation is a fertiliser plan written in beds instead of bags.
Common mistakes
- Rotating crops but not families. Tomatoes following peppers following potatoes is not a rotation; it is a nightshade residency with costume changes.
- Forgetting the volunteers. Self-sown tomatoes and stray potatoes in the wrong bed are small breaches, worth pulling where disease has been present.
- Letting the plan collapse in year two. Rotation fails by improvisation, not design. Write the four year table on the shed wall; the plan’s value compounds only if it survives contact with spring enthusiasm.
- Ignoring containers and grow bags. They do not rotate, they restart: fresh mix each year for hungry crops, and never tip spent tomato mix onto a bed earmarked for nightshades.
Putting the result to work
Label beds physically (a painted number on the frame beats memory) and keep a one line per bed log each year. When disease appears anyway, note which family and extend that family’s absence; the plan bends, it does not break. For what goes inside each family’s bed, the Plant Spacing Calculator sets densities, and the Seasonal Garden Calendar schedules the sowing year.
How do I plan a crop rotation?
- Count the beds you rotate (permanent beds and containers sit outside).
- Set bed 1’s family for this year; the others follow in the fixed order.
- Read the four year table: each bed moves one family step per year.
- Write the table down and label the beds.
- Keep each family out of a bed for at least three years; six is better where clubroot has appeared.
Why rotate by family instead of by crop?
Because the things rotation controls, soil diseases and pests, specialise by plant family, not by crop: blight moves between potatoes and tomatoes, clubroot between all brassicas. Rotating individual crops while keeping the family in place is the most common rotation mistake there is.
How many years should a family stay away?
Three to four years is the standard planning gap and handles most disease buildup, including potato blight’s soil phase. Clubroot is the exception: its spores persist far longer, and six years or more is the advice on infected land, along with liming toward neutral pH.
What order should families follow?
The classic feeding order used here: legumes (which add nitrogen), then brassicas (the heaviest feeders, spending it), then fruiting nightshades and cucurbits, then alliums and roots (light feeders that scavenge). Any consistent order that keeps families apart works for disease; this one also manages fertility.
Can I rotate in a small garden with two beds?
Yes, imperfectly: alternate the two halves by family groups, nightshades and brassicas swapping with legumes and roots each year, and lean on containers for the family that needs isolating most (usually potatoes or tomatoes). A two year gap beats none, and fresh mix in containers resets their clock completely.
Do cover crops break the rotation?
No. Cover crops fill gaps between family years without counting as a return of any family, unless the cover itself is a legume grown a full season (which can fairly count as the legume year) or a brassica cover like mustard on clubroot land, which should be avoided there.
Family groupings follow botanical families for the main vegetable crops. The four year minimum gap and feeding order follow standard US and UK extension rotation guidance.
