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germinationUpdated Apr 2026

Why aren't my seeds germinating?

Cold soil is the most common culprit — most vegetable seeds stall below 60°F, and old or improperly stored seed may not be viable at all.

Soil temperature is the variable most gardeners overlook. A packet of tomato or pepper seed that germinates in 5 days at 80°F may take 20 days at 65°F or simply fail. Most warm-season crops need soil between 70°F and 85°F to germinate reliably. A cheap soil thermometer tells you more than any calendar date.

Seed viability drops with age and poor storage. Onion and parsnip seed are typically only good for one season. Tomato and pepper seed stored in a cool, dry place can last 4–5 years. If you're unsure about a batch, do a germination test: fold 10 seeds in a damp paper towel, seal it in a bag, and keep it at room temperature for the number of days on the packet. If fewer than 6 sprout, the seed is marginal — plant more densely or buy fresh.

Damping off is the third possibility: the seeds germinated, the seedlings emerged, and then a fungal pathogen (most often Pythium or Rhizoctonia) rotted the stem at or just below the soil line. You may see a ring of collapsed seedlings that look pinched off at the base. Prevention is a combination of sterile seed-starting mix, good airflow, and not overwatering — the pathogen thrives in soggy conditions.

Planting depth also matters. Most small seeds need only light covering — 2–3 times their diameter. Tiny seeds like lettuce and basil often need light to germinate and should be barely pressed into the surface, not buried.

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