Chapter 11 · Cool, dry, dark, named
Storing Seeds
Properly dried tomato seed keeps four to six years easily, and can sprout at ten. The enemies are moisture, heat, and an unlabeled envelope.
Zone 6: transplant Mid- to late April. Harvest June – October.
Once the seeds snap between your fingers they are ready for winter. Move them off the plate the day they are dry; they can take up kitchen humidity if they sit out.
Cool
A spare refrigerator (about 40°F) is ideal. A dark closet beats a kitchen counter. Avoid garages and sheds, where temperature swings.
Dry
Target well under 50% relative humidity. Put envelopes inside an airtight jar with a silica gel packet. Incomplete drying is the usual reason seed molds in storage.
Dark
Light ages seed. Opaque jars or a closed box in the fridge keep germination higher for longer.
Stable
Do not freeze unless seed is bone-dry and vacuum-sealed; condensation on thaw can ruin a batch. Do not store in the door of the fridge, where it warms every time you open it.
How long they last
Well-fermented, fully dry seed stored cool and dry germinates strongly for four to six years. At eight to ten years you may still get 50 percent. Unfermented seed, or seed stored in a warm cupboard, is a one- to two-year proposition. Use the oldest envelopes first. Each summer, replace what you sowed with a fresh lot from your best fruit.
A germination test in March
Ten seeds in a damp paper towel, inside a loosely closed bag, on top of the fridge. Count sprouts at day seven and day fourteen. Eight or more is a full sowing rate. Four to seven: sow thick and thin. Under four: use the backup packet.
The year as a circle
You started with a zone and a last frost date. You started seed in the weeks before it, planted after it, picked until the first freeze, and you put the best of that fruit back in a jar. Next year the plants will already know your garden. That is the whole book.
Label the envelope as if a stranger had to sow it. One day that stranger will be you, in March, holding a cup of coffee and a tray.