In this video, Ask This Old House landscape contractor Roger Cook discusses foolproof tips and techniques for starting plants from seeds.
1. Packaged seeds are much cheaper than potted seedlings and come in many more varieties.
2. Planting seed allows you to harvest two to three weeks earlier than planting seedlings.
3. Seed-starting containers can be bought or made from virtually any type of carton or plastic tub. Just be sure to punch drainage holes in the bottom.
4. Biodegradable pots can be planted directly in the ground without first removing the seedlings.
5. A divided-cell planting tray has individual compartments; plant one seed per compartment.
6. An open-style planting tray allows you to plant many more seeds than a divided-cell tray. However, the seedlings are easier to extract from the divided cells.
7. Partially fill a small plastic bucket with a mixture of sphagnum moss and vermiculite.
8. Add water and mix with a garden trowel.
9. Fill the planting trays and containers with the hydrated mixture.
10. Make a hole in the soil two to three times larger than the size of the seed.
11. Drop in the seed, cover with soil, and press down to compact the soil.
12. Scratch a shallow trench in an open-style planting tray, then sprinkle in the seeds.
13. Cover the seeds with soil, then press down to compress the soil.
14. Lightly mist the trays with water. Or add water to a solid tray (no drainage holes), then set the planted tray into the solid tray.
15. To keep the soil moist and prevent evaporation, place a clear plastic cover on top of the tray.
16. Set the tray on an electric heating pad to encourage growth.
17. Once the seedlings appear, place the tray in a sunny window or under a grow light.
18. Set the grow light close to the tray, then raise the light as the plants grow taller. Expose the seedlings to 14 to 16 hours of light per day.
19. Don’t plant the seedlings in the garden until a week or two after the last frost in your region.
20. Harden the seedlings by putting the tray outdoors for 2 or 3 hours, then bringing them back inside. Repeat for several days, increasing the seedlings’ exposure to the weather each day.
21 When it’s time for planting, gently tug the seedlings out of the tray and plant in the garden.