Why are my seeds not germinating? 10 common causes

Why are my seeds not germinating?

Seeds that fail to emerge are not necessarily poor quality. Temperature, moisture, sowing depth and the crop’s natural germination time frequently matter more than the age of the seed.

Ten common causes

1. Conditions are too cold. Peas and spinach tolerate cool soil, while peppers and aubergines require consistent warmth. Measure the compost temperature rather than relying on room temperature.

2. Conditions are too hot. Lettuce and some leafy crops germinate poorly in very warm compost. Move summer sowings to a cooler position.

3. The compost dried out. Once germination begins, complete drying may kill the developing seed. Fine surface-sown seeds are particularly vulnerable.

4. The compost is waterlogged. Excess water removes oxygen and may cause seeds to rot. Use free-draining compost and containers with drainage holes.

5. Seeds were sown too deeply. As a general rule, cover seeds to two or three times their own thickness.

6. Seeds have poor contact with the compost. Very shallow seeds may dry rapidly. Firm the surface gently after sowing.

7. The normal germination time has not elapsed. Radishes emerge quickly, while parsley and parsnips may require several weeks.

8. The seed needs special treatment. Some species require chilling, soaking or exposure to light to break dormancy.

9. The seed was stored badly. Heat and humidity gradually reduce viability. Store packets somewhere cool, dry and dark.

10. The seed has aged. Viability declines at different rates. Parsnip seed is relatively short-lived, while tomato and squash seed often remains viable for longer.

How to perform a germination test

Place ten seeds between sheets of moist kitchen paper. Keep them inside a container or bag that limits evaporation and maintain the recommended temperature.

Eight germinated seeds indicate approximately 80% viability. With a lower result, sow more densely or replace the seed for an important crop.

Should you sow again?

First allow the crop’s normal germination period to pass. If nothing emerges, correct the likely problem before resowing. Repeating the same method under unchanged conditions is likely to produce the same result.