Starting garden plants from seeds indoors can be an enjoyable project for any gardener. It's a relatively inexpensive way to get a wide variety of plants. Many garden favorites are found in a greater variety of colors, sizes and growth habits as seeds than as started plants. For the price of seeds, an adventurous gardener can experiment with raising unusual plants.

Buying Seed
Seeds are available from many sources ranging from your local building supply store to garden centers and mail order catalogs. Their prices vary greatly. The newest hybrids command higher prices, as do seeds of rare or unusual plants. Some small seeds are pelletized, coated in clay, to make them easier to handle. Others are treated with fungicide, usually a pink powder, or an inoculant to promote germination.

Packaging costs also affect price. Name brand seed companies may package their seeds in moisture-resistant envelopes inside the seed packet to prolong germination capability. Planting and care information is often more complete on name brand seed packets. If name brand and "off brand" seed varieties are the same for a given flower or vegetable, there shouldn't be any difference in the plants' ultimate quality. The percentage of germination and seed purity is governed by law.

Many companies sell different sizes of seed packets, from mini-packs for small space gardeners to seeds by the pound. Don't buy more seed than you feel you will use in two or three years; many won't be good much longer than that.

When selecting vegetable varieties, check packets for the number of days until harvest to be sure your choices will ripen before frost. Many long season vegetables must be started indoors in early spring.

Containers
Start seeds in cell packs with four or more divisions or use small peat pots. Peat pots are particularly good for raising seedlings that don't transplant well or are known to outgrow cell packs quickly. Plastic cell packs and trays are available from garden centers as well as discount and building supply stores. Cell packs from purchased plants can be re-used once they're cleaned. It's best to use divided containers, rather than open ones such as milk cartons or ice cream pails because seedlings' roots will grow into each other and may be injured during transplanting.

Seed starting mixtures
Commercial seed-starting mixes are usually composed of vermiculite and peat, without any true soil. They're sterile, light weight and free from weed seeds.

Sowing Seeds
Sow fresh seeds individually into each cell of your plastic packs according to package directions. The rule of thumb is to plant a seed four times as deep as its diameter. Think of it as planting a seed deeply enough that three more seeds could be placed directly above it. Mark each pack with a tag. Tags can be made by cutting strips from plastic milk jugs and writing on them with a permanent marker.

Some seeds require light to germinate. Cover them with a thin layer of fine vermiculite, porous enough to permit light to penetrate yet keep the medium moist enough to encourage seed germination. Place cell packs containing seeds that need darkness for germination in dark plastic bags or cover them with several layers of newspaper until seeds sprout.

When using older seeds with lower germination rates, plant two or more seeds per cell. Once the seedlings have developed true leaves, cut all but the healthiest seedling off at the ground with scissors. If you try to separate seedlings, you're likely to damage all of them.

Most seeds can be saved from year to year. As soon as you're done planting, store seed packets in an air-tight container in a cool place. To keep the humidity low in the container, add a packet of silica gel. You may use a teaspoon of powdered milk in a piece of facial tissue or paper towel instead of silica gel.

Seeds germinate more quickly in warmer soil than cool soil. Grow mats can be used to maintain an even bottom heat of 70ºF. Seed trays set on top of a refrigerator will also stay warm enough to speed germination. Once seeds sprout, move the trays to a brighter growing area. Seedlings will grow reasonably well at temperatures starting in the mid 60's; cool temperatures will help keep plants compact.

Light
If you're starting only a few plants and have roomy window sills, a south-facing window may be all the growing space you need. But it's much better to grow seedlings under fluorescent lights. Grow lights are designed to provide light in specific ranges required by plants, but standard shop lights with two fluorescent tubes per fixture also give plants adequate light and are inexpensive. Use cool white fluorescent tubes or a combination of cool white and warm or natural daylight tubes.

Hang lights from chains to ease raising them. Keep lights no more than 4" above the tops of your seedlings as they grow; lack of light is the major cause of elongated, skinny stems.

Plants need 12-16 hours of light daily. Don't leave lights on continuously as many plants need some dark period each night to develop properly.

Fertilizing
Seedlings draw energy for germination from food stored in the seed. They don't need fertilizer until they have several sets of true leaves. Seedlings grown in a soil-less mix need a weak fertilizer such as fish emulsion or general purpose water-soluble fertilizer mixed 1/4 strength. Fertilize only once a week. Water as needed the rest of the week with plain water. Drain excess water that accumulates in the tray, to prevent root rot.

Transplanting
Transplant seedlings that outgrow the cell packs into larger containers. Larger peat pots or styrofoam or plastic cups with holes punched in their bottoms are excellent. Lift seedlings by a leaf and support the rootball from below with a spoon when transplanting. Never hold the seedling by its stem, as you may crush it.

To eliminate the need for tags, write the plant's variety on masking tape stuck directly onto each cup or pot. Wash and re-use plastic and styrofoam cups as long as they last. Sterilize previously used cups and cell packs by soaking the cleaned cups in a bleach solution (1 part bleach to 9 parts cool water) for 30 minutes, then rinse.

Moving Outdoors
A week or two before planting outdoors, start hardening off seedlings by moving them outside for increasingly longer periods each day. An easy way to harden plants off is to place them in a coldframe* and adjust the lid of the coldframe every few days. If you don't have a coldframe, find a sheltered spot where you can put the trays of plants. Remember, these plants have not been exposed to full sun or widely fluctuating temperatures. If plants are not adequately hardened off, their leaves may be scorched by sun or wind; plants might even wilt and die.

Once hardened off, seedlings can be set out in the garden. Transplant on a cloudy day or late afternoon when the sun has passed its peak. Even hardened off plants may wilt when first exposed to full sun but they generally recover within a day or so.

When transplanting seedlings grown in peat pots, trim the pots down to soil level. Peat pot collars exposed to drying air will wick water away from the root zone, To encourage roots to spread out, carefully tear holes in the bottoms of the peat pots because they usually don't break down completely in the soil.