When Seeds Fail to Sprout

Seeds require many things to thrive: right watering, optimal temperatures, planting medium, moisture, air circulation, macro/micro elements and light among other things.

When vegetable seeds fail to sprout, what could the problem be? Often the answer is simple and is likely one of these:

• Temperature is either too low or too high. Check the seed packet for the seed’s optimal germination temperature. Most vegetable seeds prefer soil temperatures between 70° and 80°F for germination.

• Seed medium drying out. Seeds must absorb moisture to begin germination. The seed coat expands with water and allows the embryo to begin growth. Sometimes, seed from agri-supply is coated with fungicide, so it must be rinsed first.

• Seeds planted too deep. As a rule of thumb DO NOT plant seeds greater than the width of their diameter; this is often just ¼ to ½ inch deep and sometimes less. Most seeds require light to germinate.

• Too much water. Watering caused seeds sown just below the soil surface to become exposed and float away. Dampen the soil before you sow seed then be careful not to overwater after sowing. Or better yet, use a water sprayer, the one used for orchids will do.

• Insufficient soil contact. Seed coats are tough. Beneficial bacteria in the soil along with moisture help break down the seed coat and allow germination and growth to begin. Gently press down on the soil after you sow seed to make sure the seed and soil come in contact with each other.

• Poor soil. The best soil is half solid matter and half pore space –the pore space contains air and water.

·      Clay soil is flat with no space for air.

·      Sandy soil is too loose and does not hold moisture well.

·      Best soil should be rich in decomposed organic matter or compost (properly aged); this soil will have just what seeds and seedlings need. If you suspect the soil is poor, amend the soil with aged compost and re-sow.

• “Damping-off” disease

·       Damping-off is a fungal disease that can attack just germinated plants. It is often a sign that the soil is too moist or too rich in nutrients. Use a sterile seed starting medium or a soil substitute such as vermicompost or coco coir dust.

• Light and Dark

·      Most seeds require light to germinate; some seeds require darkness. Seeds are light sensitive. Germination often depends on exposure to red light waves–even through soil cover. Check seed packets or grower’s guides to see if special light conditions must be present for germination.

Special thanks to: 

     Steve Albert

       Master Gardener for the University of California

       www.harvesttotable.com