How to Plan a Crop Rotation

The bed count is the rotation

Move each crop family on by one bed a year and wrap around at the end. That's the whole mechanism, and it means:

With N beds, a family returns to where it started after exactly N years.

Four beds gives a four-year rotation. Three beds gives three. There's no planting order clever enough to change that, which is worth knowing before you design anything on paper.

Track one family — the rest follow

You don't need to model every group.

If you know where one family is, everything else sits in the same relative order and moves with it — the whole set shifts by one bed together. Pick the family you most need to keep away from itself, usually whichever one has given you a disease problem, and use it as your marker.

Bed it will be in does the arithmetic for any year ahead. At the defaults, a family in bed 1 goes to 2, 3, 4, and is back in bed 1 in the fourth year.

The one judgement, and why the tool won't make it

Rest interval you are working to is an input, and it's deliberately not a number this page supplies.

How long a bed needs before a family returns depends entirely on which problem you're managing, and the range is enormous — some soil-borne organisms clear in a season or two, others persist for many years.

A single number here would be confidently wrong for most readers, and wrong in the dangerous direction: it would tell someone their rotation is long enough when it isn't. Your national extension or horticultural service publishes intervals for specific problems in your area, and a local grower who's had the same problem is often better still.

What the margin tells you

Margin against your rest interval is your bed count minus that interval.

Margin	What it means
Positive	Room to spare
Zero	Exactly long enough, and one misplaced planting breaks it
Negative	Too short — the family comes back early every cycle

A negative margin isn't a planning problem, it's a structural one. If you need four years and have three beds, no arrangement fixes it. The real options are: add a bed, extend the gap with a fallow year or a cover crop, or stop growing that family for a while.

Zero isn't comfortable either. It means the rotation works only if nothing ever goes in the wrong bed.

Rotation manages a problem — it doesn't cure one

Worth being blunt about, because rotation gets talked about as though it were a fix.

It reduces soil-borne disease pressure and evens out nutrient demand. It will not clear a problem that's already established, does nothing about airborne disease, and works less well in a small garden than on a field — soil and spores travel a few feet on boots, tools and water splash far more easily than they travel a few hundred.

Treat it as one useful practice alongside variety choice, hygiene and drainage. Not a guarantee.

Two things about the plant counts

Plants per bed at that spacing assumes a square grid, which is the simple case rather than the best one.

Offset spacing fits roughly 15% more into the same bed, and it's worth using for anything you grow in quantity.

And treat the number as a maximum, not a target. A bed packed to its theoretical limit is one you can't weed or harvest without standing in it — which compacts the soil you spent effort improving. Leaving room to reach the middle isn't wasted space.

A few practical notes

• Keep perennials out of the rotation beds. Anything that stays put for years isn't rotating, and it blocks a bed permanently.
• Pull volunteers. A potato that comes up from last year's crop is that family back in the bed a year early, whatever your chart says.
• Move the whole set in the same direction every year. Reversing it or skipping a year quietly shortens the gap for everything.
• Unequal beds don't break it. The rotation depends on the count, not the dimensions — only the area and plant figures become averages.

The printable has a year-by-year table. Filling in what did badly and where is worth more after two seasons than any starting plan, because that's the data that tells you which family actually has the problem.