Saving bean seed
The most generous seed crop in this catalogue. Strictly self-pollinating, annual, and the pods dry on the plant with no intervention from you.
- Life cycle
- Annual
- Pollination
- Strictly self-pollinating
- Isolation
- 3–5 m (often unnecessary)
- Seed life
- 4–6 years
- Yield
- 1 plant gives 50–100 seed
Beans are the ideal first seed crop if you want volume. The flower fertilises itself before it opens — crossing is genuinely rare, not just unlikely — so you can grow several varieties and still get seed that comes true. One plant yields enough seed to plant a row next year.
The process is almost entirely passive: leave the pods on the plant until they are brown and rattling, then shell them.
The protocol
- 1
Stop harvesting
Choose your seed plants early and pick nothing from them. A bean plant kept in production will never commit to maturing its pods.
- 2
Wait for brown, rattling pods
Pods go from green to yellow to brown and papery. Shake them — if you can hear the seed rattle, they are ready.
- 3
Pull the whole plant if rain threatens
Beans mould inside damp pods. If wet weather is coming, pull the entire plant and hang it upside down indoors to finish drying.
- 4
Shell and inspect
Split the pods by hand. Discard any seed with a round hole — that is bean weevil, and the larva is inside. Also discard shrivelled or discoloured seed.
- 5
Dry further, then freeze
A week on a plate after shelling, then 48 hours in the freezer to kill any weevil eggs, then store in a sealed jar.
What goes wrong
Picking from the seed plants. The most common mistake. A plant harvested for green beans keeps producing them and never matures seed.
Bean weevil. Small round holes in stored seed. Inspect before storing and freeze the dried seed for two days to break the cycle.
Storing before fully dry. Bean seed that dents under a fingernail is not dry enough.
Saved seed from this crop?
Germination rates, what came true and what crossed — post it and let other growers learn from it.
All 14 protocols
Annual, biennial and vegetative crops all save differently. The index compares them side by side.