The REASONS - There are many benefits to the practice of starting seeds of both vegetables and ornamentals indoors, well ahead of their safe outdoor planting time. As well as the obvious antidote to "Old Man Winter" and cabin fever, raising your own plants adds extra weeks - sometimes months - to summer's productivity, gives far greater choice of plants/varieties, saves money, and allows you to customize the timing of your planting schedule precisely to your needs.
The INGREDIENTS - The necessary elements in this venture are simple: A growing medium, containers and labels, seeds, light, nourishment and water.
The growing medium used in the initial stage - germination - is usually not "soil," definitely not ordinary garden soil. The germinating seed needs only a medium to support it and requires excellent drainage and lots of air spaces, the pores through which water, oxygen and roots move. These necessities can be supplied by a totally soilless mixture of equal parts milled sphagnum moss, vermiculite and perlite. Garden soil alone - even your best - tends to compact and/or crust over, with not nearly the friability needed by tender new stems and roots.
Photo by Lynn Bliven
With the right ingredients such as soil, containers, seeds, light, nourishment and water, garden plants can be started indoors.
Containers and Labels - Containers to plant and grow your seeds are limited largely by your ingenuity, tempered by reasons of space, available light and the tolerance of your family. Do keep in mind that any container must have drainage holes, and if possible, set in a larger container to allow bottom watering. All must be scrupulously clean. If reusing old plastic or ceramic pots, scrub in soapy water (use an old bottle brush), and rinse in a solution of nine parts water to one part chlorine bleach. A fungal disease known as "Damping Off" is perhaps the number one enemy of young seedlings. It attacks quickly and is irreversible once symptoms show - the lower plant stem will appear shriveled, though the leaves appear healthy; the plant will topple over and die. The fungus thrives in overwatered, overcrowded conditions, especially when too heavily fertilized (nitrogen in particular). It can overwinter in old containers, or be carried by non-sterile soil mixes. If you see it, remove affected plants immediately, increase air movement, decrease water and hold off on fertilization for a few days or more.
Labels can be popsicle sticks, strips of metal from old window blinds, plastic strips cut from milk jug ... use a wax pencil or indelible marker to record plant name, date sown and perhaps expected germination date.
Seeds - Your seed packets or catalog should list the variety's growth and needs. You'll want to know: light or darkness requirements for germination, temperature needs for germination and growth, anticipated number of days for germination, and number of weeks before planting out into the recommended outdoor conditions. The first two are fairly general. Most vegetable seeds require darkness (soil coverage) to break dormancy. Flowers are more varied in their demands. Most seeds of both flowers and veggies need 70 degrees to 80 degrees temps (soil temp) for germination; once the seeds have germinated the plants then prefer 60 degrees to 70 degrees for continued growth, with 10 degrees lower at nighttime.
Next, get out a calendar and count back the recommended number of weeks from the date of the last frost anticipated for your area (CCE Master Gardeners can help if you don't know this critical date) and sort your collection of seed packets into groups which require approximately the same number of weeks to planting out. Don't be tempted to plant everything at once. Ideally, you want to grow plants that are mature enough to endure the fickle conditions of life in the real world once set out, but not so old as to be "stagnating" in their restricted indoor growing environment. Plants should be able to grow on unchecked from germination to planting out. Some plants, cauliflower for one, may not ever recover if its growth is held back by a long spell of waiting for the weather to settle out
Light - An ideal arrangement of a few double-tube florescent light fixtures in an out-of-the-way place is well within most people's reach. Plant "grow lights" aren't necessary, unless you need your seedlings to be in bloom before planting out. A fixture with one cool white and one warm white tube is best, but even that isn't critical. You can make better use of available light by covering sheets of cardboard with aluminum foil to reflect more light rays onto your plants rather than it dissipating into surrounding low light areas. Prop these around the seedling flats. Lights should be close to the tops of your plants without touching them, from 2 to 4 inches above is best. Sunny windowsills are rarely suitable. Often drafty, the plants will receive weak light for part of the day, then occasionally hot, baking conditions which can dry soil too quickly. Wintertime sunlight is, at best, of a low intensity.
The PROCESS - Spread a sheet of newspaper out on your table, fill all containers to within 1/4 inch of their tops with your growing medium and set them in shallow pans of warm water until the soil appears darker, the water will be taken up through the drainage holes in your containers. It is much easier to thoroughly moisten the soil before sowing than to have to water afterward, displacing your carefully positioned tiny seeds. Place the labels you have already made and insert them in the appropriate place. It's quite easy to get carried away placing seeds, only to forget which variety you put where.
Place 2 to 3 seeds per pocket, if using divided packs; sparsely in rows if using flats. Seed should be covered (I use pure vermiculite; It doesn't crust over and combats the damping-off fungus) to a depth of no more than three times their size. (Fine, dustlike seed should be merely pressed gently into the soil surface.) This covering needn't be moist as it will absorb enough moisture from the soil below. Cover the flat with a sheet of newspaper for darkness, and/or plastic to retain moisture, creating the humid environment needed for germination. Set flats in a warm place - above your refrigerator or hot water heater, near a wood stove, over a radiator. (Remember that nothing is quite so appealing to a house cat as a tray of loose soil!!) Check daily for the first signs of growth and remove the covering as soon as several green "elbows" appear. If only a few seeds have germinated, find a way to keep a covering over those which haven't yet come up. If all the seeds planted in the same flat have approximately an equal number of days to germination, this should not be a problem.
Set flats immediately under lights; they should get 12 to 16 hours of good light per day. Darkness is equally important, as plants "digest" the energy they've gathered during light hours, growing more on the sides away from the light source. That is why, if your light source is strongly lopsided, so will your plants be!
Water and Fertilizers - As soon as seedlings grow their first "true leaves" (not the "cotyledons," or seed leaves), they require supplemental fertilization. Water-soluble plant foods are perfect for seedling programs. For the first week or two, this should be diluted to half strength. Water only when the soil is dry! The over zealous gardener often kills or weakens their young plants by overwatering. If your setup uses holeless trays beneath the seedling flats or packs, bottom watering works beautifully. If water remains in the bottom tray hour after watering, drain it off. Next time use less. As seedlings grow, fertilize every third or fourth watering but no more than every 10 days.
Thinning and Transplanting - With the of the seedling's first true leaves, it's time to thin or transplant. To thin-pinch off or snip with a small sharp scissors, any seedling which crowds its neighbors closer than a inch spacing, leaving the strongest plants. Don't pull up the extras as this can cause root disturbance for the remaining seedlings.
Before transplanting seedlings within containers, first water the flat well. Seedlings experience less shock if their stems are turgid. Using a table fork or pencil, gently pick out a group of seedlings; separate out only one and, holding it by a leaf, not the tender stem, move it to a new pot. Settle the seedling at least as deep as it was previously growing, deeper if it is a tomato, pepper or marigold. These have the ability to grow roots all along the stem as it is buried, giving greater growth potential. Plants which have a leafy crown, such as lettuce, cabbage and many flowering plants should never have soil pushed into that crown as it encourages rot.
Hold off on watering for a day, shading the new transplants from strong light if they appear wilted. They'll resume their routine and GROW ON!! Transplant seedlings as often as they need more space (root space especially) until ready to plant outside. Remember: Sow sparsely, thin ruthlessly, transplant early and often, if needed.
Many flowering plants, but few vegetable seedlings, benefit from being "pinched" as they grow, encouraging compact, bushy growth and therefore more flowers. Simply pinch above a leaf node, removing the tip growth; this signals the plant to branch out. Plants also benefit from the loving touch of the gardener. Every few days, lightly brush your hand over the growing seedlings. This, as well as the gently moving air from a fan, encourages stocky, healthy growth - a little early "hardening off." Now that you have all of the basics down, try starting some seeds indoors this year.
Debbie MacCrea is a community educator with Cornell University Cooperative Extension of Allegany and Cattaraugus counties.