Why Won't My Seeds Germinate?
Seeds usually fail to germinate because they are old or nonviable, planted at the wrong depth, kept too wet or too dry, or started in soil that is too cold. Begin with fresh seed, correct planting depth, clean seed-starting mix, and the crop's preferred soil temperature.
Check seed age and storage first. Viability declines at different speeds depending on the crop and storage conditions, and seed kept hot, humid, or exposed to repeated temperature swings loses vigor faster. Use current-season seed when possible, store unopened or well-sealed packets cool and dry, and test questionable seed by sprouting a small sample in a moist paper towel before planting the entire packet.
Planting depth matters because a seed has limited stored energy. A practical rule is to plant many seeds about two to three times as deep as their diameter, though fine seeds are often surface-sown or only lightly covered. Read the packet because some species need light to germinate, while others germinate best when covered.
Soil temperature, rather than air temperature, determines how quickly many seeds sprout. Warm-season crops such as peppers, tomatoes, beans, squash, and cucumbers can rot or germinate slowly in cold soil. Cool-season crops such as lettuce, peas, spinach, and many brassicas tolerate cooler conditions, but each crop still has a useful temperature range listed on its packet or by local Cooperative Extension resources.
Moisture should be steady but never waterlogged. The medium should feel like a wrung-out sponge, with enough air spaces for roots to develop. If a tray dries completely after sowing, a newly germinating seed can fail; if it remains saturated, fungal decay and poor oxygen availability can prevent emergence.
Use clean containers and a fresh, fine-textured seed-starting mix rather than dense garden soil. Garden soil can crust at the surface, drain poorly in small cells, and carry organisms that damage seedlings. Cover trays with a humidity dome only until most seedlings emerge, then remove it and provide bright light and airflow.
Finally, allow enough time before assuming failure. Germination can vary widely by species, temperature, and seed freshness, so compare the sowing date with the expected range on the packet. Dig carefully into a single cell to inspect one seed: an intact dry seed suggests inadequate moisture or temperature, while a soft, dark, decaying seed points to excess moisture, cold conditions, or poor seed quality.
Frequently asked questions
Should I soak seeds before planting?
Some large or hard-coated seeds may benefit from a short soak, but it is not required for most garden seeds. Follow packet guidance and plant promptly after soaking so seeds do not remain deprived of oxygen.
Why did my seeds sprout in a paper towel but not in soil?
The soil may have been too cold, too wet, too dry, planted too deeply, or crusted over. A paper towel test shows viability, but seedlings still need suitable soil conditions to emerge.
Can I reuse old potting mix for seed starting?
It is safer to use fresh seed-starting mix for germination. Reused mix may be compacted, retain salts, or harbor organisms that increase the chance of seedling problems.
General guidance for US home gardens. Conditions vary by region and season; check with your local Cooperative Extension office for site-specific advice. Page updated Aug 4, 2026.