The Easy Way to Start Seeds

Growing your own plants from seeds can be easy, economical and fun. It also gives you the freedom to choose from the hundreds of varieties available right now in catalogs, do you don’t have to wait for spring.

Here are some tips for starting seeds:

Plan ahead. Order or buy your seeds and supplies early so you can start them at exactly the right time. Be sure to read the seed packet to learn the best growing conditions for that particular plant. Hint: the last frost date in the Philadelphia is between May 1 and Mother’s Day, so count backward from then. If the packet directions read “start six weeks before last frost,” plan to plant around March 25.

Pick quality seeds. Choose from a reliable company and check the expiration date on the packet. Seeds from years gone by will germinate as well, so sow more thickly.

Use clean containers. Wash used ones with soap and water and rinse well. Make sure they offer good drainage or seeds can rot. Make sure you have a drainage tray underneath or you’ll ruin your windowsills.

Use sterile soil. Or a soilless potting mix. Also make sure the soil has no fertilizer in it, as that can cause tender seedlings to burn.

Think warm. Most seeds need warm soil to germinate. The top of the refrigerator is good spot, but do not use the radiator—it gets too hot. Some people use a plant heating pad; others count on the heat from a light unit to keep seeds warm once they sprout.

Lighten up. Seedlings need between 12 and 16 hours of light per day, so a light unit is better than a sunny windowsill. If you get that much natural light in your house, call me—I’m moving in with you for the winter! Keep the level of the lights about 6” above the tops of the plants.

Keep them moist, but not wet. If the soil stays wet, the rotting disease (“damping off”) can kill the plant’s stems. Water with room temperature tap water, unless you have rainwater stashed away. Keep tiny plants moist by covering with a plastic bag or dome. Make sure it doesn’t touch the leaves and remove it when the plants get bigger.

Feed them gently. Seedlings don’t need any fertilizer until they get their second true leaves; up until then, the food inside the seed will suffice. Use a half-strength dilution of your favorite plant food once a week.

Harden them off. Get your little plants ready for the great big outdoors. Four or five days before planting, take them outside for a few hours each day, then bring them back in at night. Increase the day length each day until you’re ready to plant.

by Sally McCabe, Project Manager
The Pennsylvania Horticultural Society