Starting your own plants from seed is not only one of the most rewarding gardening experiences, but it can also save you a small fortune! Also, many species and varieties are simply unavailable unless you ‘grow-your-own’.
Choosing seeds is the first step and there are many reputable companies that offer catalogs. Besides the fun of browsing through them, mail-order companies are generally good about dealing with any problems you might encounter. When buying seeds through retail outlets, be choosy. Those 10/$1 seeds may not be such a bargain if they don't grow! Check the package for date and complete growing instructions. A reputable seed company will also list the Latin name and the germination percentage you can expect. If you've acquired seeds from a GardenWeb swap or other seed sources, don’t forget to ask for any information the grower can provide.
You can use almost any container as long as it will hold 3-4 inches of growing medium and has drainage holes in the bottom. Flats with liners are nice, but ‘recycled’ containers will also work. If you are reusing containers, follow these cleaning instructions to avoid contracting the dreaded damp-off fungus disease.
Seeds need a loose, porous, fine-textured medium, one that won't develop a crust on the surface that can interfere with emergence. ‘Potting soil’ is an extremely variable product, many retail brands (especially the bargain types) will give disappointing results in seed-starting. A 'soil-less’ mix will make your growing experience much easier. Some common ingredients in soil-less mixes:
Vermiculite - a heat-expanded rock that can be used alone or in combination.
Milled sphagnum moss (not the same as peat moss unless it says ‘sphagnum peat') - has the benefit of inhibiting damp-off fungus. Miixed with vermiculite it is frequently used by professionals.
Peat moss (sometimes called 'Michigan peat' or 'peat humus') - a heavier, more difficult to wet and more variable product than sphagnum moss. It is common in retail mixes sold for starting seeds, and is often used in combination with perlite or vermiculite. It’s (much!) cheaper than sphagnum-containing mixes, but can be more difficult to handle, especially for the beginner.
Don't start seeds too early. There's a wide variation in optimal indoor starting times and unless you have lots of room, starting too early can be stressful - for you and your plants! You may want to consider starting perennials in summer for fall planting, as many perennials don't bloom the first summer. You will save room for annuals and veggies that really need a head start in temperate climates.
Fill containers allowing an inch or so from the top for easier watering and moisten well. Allow excess water to drain. Your sowing medium should be moist, not soggy. Press the medium down lightly to eliminate air pockets.
Sow the seeds on the surface and cover with additional dry medium to the proper depth. A general rule is twice the diameter of the seed. Very tiny seeds, or those requiring light, are surface-sown without covering. Mist the medium well and cover with clear plastic. A 13-gallon clear kitchen trash bag fits a standard flat perfectly. (Look for the kind with handles and tie them loosely). Important note: Don't put a plastic-wrapped container in direct sunlight.
For plants that will benefit from transplanting - like tomatoes and lettuce - a number of seeds can be planted in larger containers and transplanted to individual pots when seedlings are large enough to handle. For those plants that dislike transplanting - such as melons - plant 1-3 seeds in individual containers. This can also save you time later on.
A temperature of 65-75 degrees is suitable for the vast majority of common plants, but there are many exceptions, so be sure to read your seed packet for the correction information. Check at least daily, and remove the plastic when seeds begin to sprout. Seedlings need intense light to grow strong and stocky, fluorescent lights are your best bet. Position so that seedlings are 2-4" from lights, 14-16 hours a day. A timer will help automate the process. If space under lights is limited, you can try rotating them in 12-hour shifts. Keep a close eye on them and adjust heights as needed.
Containers enclosed in plastic should not require watering until seeds germinate. Once plastic is removed, monitor closely. Seedlings should never be allowed to dry out completely and should be kept moist until roots begin to penetrate the medium. To allow air into the medium and encourage roots to spread, allow the medium to become dry 1/4-1/2" down before watering. If you've used a soilless mix, begin fertilizing 4-5 days after germination with a water-soluble 15-30-15 (or similar) fertilizer at half the recommended strength weekly. If you are interested in organic growing, try fish emulsion and seaweed extract at recommended rates.
When they're big enough to handle,usually when they have 2-3 sets of leaves, it's time to move them to individual containers or space them out if you have them in a community flat. Those sown in individual containers should be thinned to the strongest seedling by snipping off the extras with scissors. Now that damping-off disease is less of a risk, you may want to use a part-soil mix for ‘potting on’ - one part sterile potting soil to two parts vermiculite or perlite and/or sphagnum or peat.
Very carefully dig up the plants with a knife or wooden label, taking care to get under the roots. Separate them gently, handling them by the leaves rather than the easily-damaged stems . Use a pencil to help untangle the roots and use the same pencil to poke a hole in the soil. Your hole should be deep enough so that the roots can dangle and the seedling can be placed at the same depth it was growing previously. Firm the soil around the roots, and water well.
Weather permitting and after the danger of frost has past, seedlings at this stage may be moved outdoors or grown indoors for larger transplants. But before transplanting them permanently, seedlings or young plants must be ‘hardened off’ over a period of 10-14 days. Begin by putting plants out in the shade and provide some shelter from the wind. Gradually expose them to sun, an hour at first and increasing an hour each day. Cut back on watering, but don't let them go completely dry.
Once they're hardened off, they're ready to go outside permanently - where they belong! If possible, choose a cloudy day . Again, handle the roots with care and set the plant at their previous growing depth. (Tomatoes, however, benefit by being planted deeper as roots will form along the stem.) Firm the soil around the roots and water well. A dilute solution of water-soluble 15-30-15 fertilizer (a teaspoon to a gallon of water) will help stimulate the roots. When all your plants are in the ground, fix yourself a tall, cool one and celebrate!
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