In my life the earliest harbinger of spring is the appearance in late March of the long folding table, the kind you see at potluck church suppers, against one wall of the dining room. Marjorie drags it up from the basement and soon it is covered with trays of cell-packs planted to seeds of sweet peas and nasturtiums, onions and tomatoes.

So begins two months of indoor gardening, of watering, fertilizing, transplanting, adjusting lights, moving trays of plants to and from the porch, until finally the sturdy little transplants are set out into the garden beds. When asked why she goes to all of this effort, considering the variety of transplants available from nearby garden centers, Marjorie gives the only honest answer: You either start gardening in March or go insane.

Experience sets the schedule if you have been growing your own transplants for years. Newcomers should rely on the seed catalogs for planning information. For example, seeds of onions and pepper need a long time to germinate, so the seed catalog will tell you to sow onion seeds indoors in late February or early March, peppers eight weeks before transplanting outdoors. Producing sturdy tomato transplants, on the other hand, takes only five to six weeks.

Backward planning is the key. Identify the last frost date for your garden site and schedule the seed-sowing based on the timing recommended by the seed catalog. Despite the incipient insanity, don’t start too early! The resulting pot-bound, leggy transplants will remain stunted after planting in the garden and produce poorly.

Here are some keys to success in growing your own:

. Seeds planted in cold, wet soils tend to germinate slowly if at all. Reduce the germination time with bottom heat, maintaining a soil temperature between 65 and 70 degrees Fahrenheit. Heating mats and soil thermometers are available from mail-order garden supply houses.

. Use a sterile growing mix with a starter nutrient charge and a wetting agent. I recommend both Fafard No. 2 and Pro Mix. Wet the mix ahead of use to the moisture content of a wrung-out sponge.

. Use new or sterilized 2- to 3-inch peat pots or cell packs with similar size cells. Seeds and seedlings stay too wet for too long in larger pots.

– . Sow two to three seeds per pot or cell, planning to thin to the sturdiest seedling after the first set of true leaves develop. (Don’t mistake the early leaf-like “seed leaves,” or cotyledons, for true leaves.) When thinning, remove unwanted seedlings by cutting them at the soil surface rather than pulling them out.

. Sow the seeds on the surface of the growing mix and cover with a thin layer (about twice the diameter of the seed) of a fine-textured germinating mix such as Ready-Earth. Particles in the courser growing mix can impede germination when used to cover small seed.

. Cover the pots or cell packs with a loose layer of clear plastic (shrink-wrap works well) to maintain uniform moisture.

. Once the seeds have germinated, remove the cover and the bottom heat. Optimum growing temperatures, both in the air and soil, are 65 degrees Fahrenheit during the day, 60 degrees at night.

. Provide supplemental lighting as soon as the seedlings emerge; window light alone is too low in both duration and intensity. Standard fluorescent tubes are adequate. Keep the lights on for 14 hours each day, maintaining the tubes 2- to 4-inches above the growing seedlings.

. Water the pots gently and thoroughly on planting day, then as often as necessary to avoid excessive drying. Be careful, however, not to keep them too wet; let the surface of the soil dry between watering. When you do water, use a half-strength solution of water-soluble fertilizer to provide essential nutrients. Water from above to leach excess nutrients from the pot.

. Before transplanting your seedlings to the garden, they must be hardened off with a slow transition to outdoor conditions. Begin by setting them outside (temperature above 45 degrees) in partial shade for one or two hours per day, gradually increasing both the light and the length of exposure over a two-week period.

Additional tips and suggestions, including plans for an inexpensive support for growing lights, are contained in an excellent publication “Jump Start Your Garden” available from University of Maine Cooperative Extension’s Home Horticulture Program in Hancock County. To receive a copy, call 1 (800) 287-1479. I also recommend “The New Seed-Starters Handbook” by Nancy Bubel (Rodale Press, 1988).

Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to reesermanley@shead.org. Include name, address and telephone number.