Why have my seeds not come up?
A checklist in the order that finds the fault fastest — depth, temperature, moisture, age, and the seeds that need special treatment.
- Difficulty
- beginner
- Time
- 20 min
- Read
- 3 min
Short answer
Sown too deep is the most common cause. Cover a seed to about twice its own diameter and no more, and leave very fine seed uncovered on the surface. After depth, check soil temperature, then whether it dried out at any point, then the age of the seed.
Different species need very different conditions, and the packet is usually right about them. Most failures come from a small number of repeated mistakes rather than from anything exotic.
What you'll need
- Seed packet
- Thermometer
- Fresh compost
Step by step
- Check the sowing depth.Roughly twice the diameter of the seed. Large seeds like beans and squash 40 to 50mm; medium seeds 25mm; small seeds 10mm; very fine seed such as lettuce, foxglove and begonia pressed onto the surface uncovered.
- Check whether it needs light.Some seed will not germinate in the dark — lettuce, foxglove, snapdragon, begonia and busy lizzie among them. Covering those with compost stops them entirely.
- Check the temperature.Most vegetables want 15 to 20C. Parsnip, carrot and lettuce germinate in cooler soil; aubergine, pepper and cucumber need 20C or more. Lettuce actually refuses to germinate above about 25C.
- Check the moisture was constant.A seed that has taken up water and then dried out is dead. The compost needs to stay evenly damp throughout, not wet then dry.
- Check the seed is not too old.Parsnip and onion seed is effectively one-year seed. Most vegetable seed keeps two to four years in cool dry conditions. Seed kept in a damp shed fails much sooner.
- Test viability on kitchen paper.Ten seeds on damp kitchen paper in a bag on a warm shelf. If none germinate in the expected time, the seed is at fault rather than your conditions.
- Check for special requirements.Some seed needs cold treatment, some needs scarifying, some needs soaking. Sweet peas, hardy trees and many perennials fall into this group and the packet will say.
- Consider what ate it.Mice take peas, beans and sweetcorn from the ground. Birds take large seed. Slugs take seedlings the night they emerge. Missing seed is not failed seed.
- Check it is not simply too soon.Parsnip takes three weeks, parsley can take a month, carrots two to three weeks in cool soil. Give the packet time before resowing.
- Resow into fresh compost with the corrections made.Fresh seed compost, correct depth, correct temperature, even moisture, and a cover if birds or mice are the problem.
Tips
- Twice the seed's own diameter, and no deeper. Most failures are here.
- Lettuce will not germinate in hot compost — sow it somewhere cooler in July and August.
- Ten seeds on damp kitchen paper tells you in a week whether the seed is the problem.
Common mistakes
- Covering fine seed with compost — Fine seed has no reserves to push through soil and several species need light to germinate at all. Press it onto the surface and keep it damp instead.
- Sowing outdoors as soon as the packet's earliest date arrives — The dates assume workable soil at a reasonable temperature. Cold wet soil in March rots seed rather than germinating it, whatever the packet says.
If it doesn't work
Nothing at all after the expected time
Cause: Too deep, too cold, or dead seed — Fix: Test viability on kitchen paper, then resow shallower and warmer.
Patchy germination
Cause: Uneven moisture or uneven depth — Fix: Sow into a level firm surface and water evenly with a fine rose.
Seed germinated then vanished
Cause: Slugs, birds or mice — Fix: Protect with fleece, cloches or netting from the moment of sowing.
Only germinated where the compost was thin
Cause: Sown too deep across the rest of the tray — Fix: Resow at half the depth.
Questions people ask
How deep should I sow seeds?
About twice the seed's own diameter. Very fine seed goes on the surface uncovered, large seed like beans goes 40 to 50mm down. Depth is the single most common cause of failure.
How long does seed last?
Most vegetable seed two to four years stored cool and dry. Parsnip and onion are the notable exceptions and are best bought fresh each year.
Why did my carrots not come up?
Usually cold or dry soil, or the seed dried out mid-germination. Carrots take two to three weeks and need constant moisture over that time, which in a dry spring means watering the drill.