Starting plants from seed in your home is a good way to get a head start on the growing season.
Growing Medium
Various books and internet sites provide recipes for mixing your own growing mediums. Soilless recipes are usually a combination of sandy loam, sand, vermiculite, perlite, fertilizers and peat. It’s only economical if you mix a large quantity. It is messy and it’s recommended that the growing medium be pasteurized to kill harmful fungi, bacteria, weed seeds and nematodes which it may contain. This is done by placing the soil mix in a shallow metal pan, covering the pan tightly with aluminum foil and heating the soil to 160oF in an oven. Be prepared for a rather unpleasant odour to fill your house during the soil sterilization process. Most people can’t be bothered.
Premixed growing mediums (soil and soilless mixes) can be bought in nurseries and stores. Soilless mixes may be a little more expensive than the home mix, but they are convenient and can be used right from the bag.
Containers
Any shallow container at least three inches in depth makes a suitable plant growing box. Recyclers can use milk cartons, foam cups and yogurt containers. Punch holes in the bottom of any container to allow water to drain from the soil. If you don’t have enough containers on hand, you can purchase windowsill seed starter packs.
Sow seeds in rows 2 inches apart, or one or two seeds per section. If enough growing space is available, plant seeds directly into individual pots thereby eliminating the initial transplanting. Crowded seedlings become weak and spindly and are more susceptible to disease. Wider spacing or larger containers permit stronger growth. If seedlings touch, remove some and transplant to give them more room to grow.
Seedings
Check the seed package to determine the optimum seeding date. Seedlings are ready to transplant when they have the first set of true leaves. Peppers generally require 7 to 8 weeks and tomatoes 5 or 6 weeks to grow to transplanting size. Squash and cucumbers require only 2 to 3 weeks to grow to an ideal transplant size. Flowering annuals also vary in the time required to produce a size suitable for transplanting.
Transplanting
When working with transplants, always hold them by the root ball or by the leaves, never the stem. Space transplants so that the leaves of one plant do not touch those of another. Set the seedling at the same level it was in the seedling flat. When firming the soil avoid injuring tender stems.
Immediately after transplanting, water each seedling container thoroughly. Wilting at this point can damage young plants. To prevent excessive wilting, shade plants from strong sunlight for a couple days after transplanting.
Both heat and light are needed for plant growth, and the relationship between the two is critical. A common mistake among home gardeners is to keep plants at too high a temperature for the amount of light they receive. The result is limp, leggy seedlings.
