Why Wont My Seeds Germinate?
Seeds can fail for several ordinary reasons: cold or waterlogged compost, dryness, excessive sowing depth or seed that has lost viability. Before sowing again, inspect the tray and packet rather than adding more water at random. A simple check of temperature, moisture and timing usually identifies the likely cause.
Begin with the sowing conditions. Tip a little compost from an unsprouted area into your hand: it should feel damp like a squeezed sponge, not dripping or dusty. Cold, saturated compost excludes air and can rot seeds before they sprout. Move indoor trays to a brighter, gently warm place, but do not place them directly on a hot radiator. Outdoors, wait until the soil has warmed enough for that crop, particularly for beans, courgettes and sweetcorn. In early spring, a cloche can warm a prepared bed, while a greenhouse or windowsill helps tender crops begin in module trays. Match your sowing date to the packet and your local conditions.
Check the packet for its sow-by date and how it has been stored. Seed kept cool, dry and dark generally lasts longer than seed left in a damp shed or warm greenhouse, but viability varies greatly between crops. If you are uncertain, place ten seeds on damp kitchen paper in a labelled container, keep it at the recommended warmth and check over the following days. This is a useful indication, not a laboratory test. If only one or two sprout, buy fresh seed from a garden centre. Do not assume old seed is always useless, but sowing more of it can create uneven spacing and wasted compost.
Use the correct depth instead of burying seed by habit. Very small seed, such as lettuce, is best sown on the surface or covered only lightly with fine peat-free compost. Larger seed needs a deeper covering, usually according to the packet instructions. A seed buried too deeply may exhaust its stored energy before reaching light and air; one left fully exposed may dry out or be moved by watering. Make a shallow, even drill outdoors and sow thinly. In trays, use individual modules where practical, then label each variety and date. Firm compost gently after sowing so seed has contact with moisture without being compressed.
Water gently and consistently from sowing until seedlings establish. A fine rose on a watering can, or watering the tray from below for a short period, prevents seeds being washed into corners. Check daily in warm weather because the top layer of peat-free compost dries first. Covering a tray with a clear lid can retain moisture, but remove it as soon as shoots appear and ventilate regularly to avoid stagnant air. Outdoors, protect freshly sown drills from heavy rain and birds with mesh or a light cover. Do not keep adding water when compost is already wet; allow surplus moisture to drain before watering again.
Consider whether the seed was sown at the wrong time for its temperature needs. Parsnips and some brassicas can germinate in cool conditions, whereas French beans and cucumbers may sit inactive or rot in cold soil. In southern Britain, outdoor soil often warms earlier than in exposed northern gardens, Wales or Scotland, but wind, shade and soil type matter as much as postcode. Delay tender crops until after the likely last spring frost and until days are reliably mild. If weather is unsettled, sow a modest number in modules under cover instead of risking the whole packet outside. Harden seedlings gradually before planting them out.
If seedlings have emerged but then disappeared, the problem is different from failed germination. Check for slugs, mice, birds, drying compost and overcrowding. Protect trays and rows with suitable barriers or mesh, and water before seedlings wilt rather than after. Avoid repeatedly disturbing the compost to search for seed, as this can damage emerging roots. Label every sowing so you know how long it should reasonably take; germination can be slow during cool spells. When resowing, use fresh compost, clean trays and a new position in the row. Keep notes, because a recurring problem may point to a cold or poorly drained site.
Frequently asked questions
Should I soak seeds before sowing?
Some large seeds can be soaked briefly if the packet suggests it, but soaking is not a cure for cold or waterlogged compost. Sow them into moist, free-draining compost straight afterwards. Small seed is usually easier to handle dry, and many crops germinate perfectly well without any soaking at all.
How long should I wait before resowing?
Use the packet's expected germination period, then allow extra time if conditions have been cool. Check one or two seeds carefully before resowing the whole tray. If they are soft, mouldy or absent, start again; if they are firm and beginning to sprout, improve warmth or moisture instead.
Can I use compost from last year's pots?
It is better to use fresh peat-free seed compost or fine multipurpose compost for sowing. Old pot compost can be compacted, unevenly fertile and home to pests or disease spores. Reuse it later as a soil improver or mix it into ornamental containers, provided it is free from obvious problems.
General guidance for UK home gardens and allotments. Conditions vary by region, soil and season; the RHS or a local garden centre can give site-specific advice. Page updated 19 Sep 2026.