Starting seeds indoors will give you earlier vegetables and flowers, and your cultivar choices will be endless. The process of germination may seem complex, but the act of seed planting is reassuringly simple. Just take it step-by-step, and you’ll soon be presiding over a healthy crop of seedlings.
Select your work area—a surface at a comfortable height and close to a water supply where you’ll have room to spread things out. Assemble your equipment: seed-starting containers, starting medium or soil mix, watering can, labels, marking pen, and seed packets.
You can start seeds in almost any kind of container that will hold 1 to 2 inches of starting medium and won’t become easily waterlogged. Once seedlings form more roots and develop their true leaves, though, they grow best in containers that provide more space for root growth and have holes for drainage.
You can start seedlings in open flats, in individual sections of a market pack, or in pots. Individual containers are preferable, because the less you disturb tender roots, the better. Some containers, such as peat pots, paper pots, and soil blocks, go right into the garden with the plant during transplanting. Other pots must be slipped off the root ball before planting.
Square or rectangular containers make better use of space and provide more root area than round ones do. However, individual containers dry out faster than open flats. Many gardeners start seeds in open flats and transplant seedlings to individual containers after the first true leaves unfold. Choose flats and containers to match the number and types of plants you wish to grow and the space you have available.
Excellent seed-starting systems are available from garden centers and mail-order suppliers. You can also build your own wooden flats. If you raise large numbers of seedlings, it’s useful to have interchangeable, standard-sized flats and inserts.
You can reuse your seedling containers for many years. To prevent problems with dampening off, you may want to sanitize flats at the end of the season by dipping them in a 10 percent solution of household bleach (1 cup of bleach plus 9 cups of water).
Homemade containers: You can recycle milk cartons and many types of plastic containers as seed-starting pots. Just be sure to poke a drainage hole in the bottom of each. Cut lengths of clothes hanger as a frame for your flats so you can wrap them in plastic to encourage germination. You can bend the wire to fit into a plastic flat filled with pots or six-packs, or staple the wire to the sides of a wooden flat as shown at right. Use clear plastic wrap or plastic bags (like the ones from the dry cleaner) to enclose the flat.
Two make-at-home seed-starting containers are newspaper pots and soil blocks. To make pots from newspaper, begin by cutting bands of newspaper about twice as wide as the desired height of a pot (about 4 inches wide for a 2-inch-high pot). Wrap a band around the lower half of a jar a few times, and secure it with masking tape. Then form the bottom of the pot by creasing and folding the paper in around the bottom of the jar. You can also put a piece of tape across the pot bottom to hold it more securely in place. Slip the newspaper pot off the jar. Set your pots in high-sided trays with their sides touching. When you fill them with potting mix, they will support one another. There are also commercial molds for making newspaper pots.
Soil blocks encourage well-branched roots and produce good seedlings. You can buy molds to make soil blocks, but making them is a messy, labor-intensive process.
Begin by mixing a wheelbarrow-load of potting soil. Use plenty of peat moss and lots of water to make a thick, wet, gummy mass with the texture of peanut butter. Jam the soil-block mold into the block mix. Press the mold hard against the bottom of the wheelbarrow, and then lift and eject the blocks from the mold onto a tray. Then arrange the blocks in flats and plant directly into them. Don’t let soil blocks dry out: Because of their high peat content, they don’t absorb moisture well once they have become dry. Water from the bottom or mist gently until roots grow. Once roots fill the blocks, they become solid and easy to handle.