The short version
Root crops and fast growers are better sown where they will stay. They dislike root disturbance, and the time saved indoors is lost again to the check of transplanting. Soil temperature, not the date, decides when to start.
What you need
A prepared seedbed
Raked to a fine crumb. Big clods leave air pockets that dry seed out.
A soil thermometer, or patience
Most seed needs the soil at 7°C to 10°C (45°F to 50°F) at minimum. Cold wet soil rots seed rather than germinating it.
Something to mark the row
A line and a cane. Straight rows make it obvious what is a seedling and what is a weed.
How to do it
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Wait for the soil, not the calendar
Soil warms weeks later than air. Squeeze a handful: if it holds together in a wet ball, it is too early.
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Rake to a fine tilth
Break the surface down to crumbs. Firm it lightly so seed sits in contact with soil rather than air.
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Draw a shallow drill
Use the corner of a hoe or a cane. Depth is the seed's own size two or three times over.
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Sow thinly
Thick sowing wastes seed and guarantees a thinning job. Space as the packet says, then space again.
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Cover, firm and water
Backfill, tamp gently with the back of the rake, and water with a fine rose so you do not wash the row out.
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Thin without regret
Thin to the final spacing while they are small. Every seedling left too close makes all of them smaller.
When it goes wrong
Patchy germination
- Soil
- Water
Dry patches, cold soil, or seed sown too deep. Keep the drill damp until the row is up.
The whole row disappears overnight
- Slugs
- Birds
Slugs on a mild damp night, birds by day. Netting handles birds; slugs need a torch after dark.
Weeds outrun the crop
- Timing
Weed the row before sowing, and hoe between rows while weeds are still seedlings.
Frequently asked questions
How do I know the soil is warm enough?
A soil thermometer at 5 cm (2 in) is the reliable answer. The traditional one is whether weed seed has started germinating on its own.
Why did nothing come up?
In cold soil, seed sits and rots. In dry soil, it germinates and then dies. Both look identical from above.
