Starting your own seeds indoors may seem like a complex process, but it really is very simple and will give you an endless range of flower and vegetable cultivars from which to choose.

Containers
Seeds can be germinated in an open flat, individual pots or sections of pots like six-packs or four-packs. Individual containers or sections of containers are preferable; the less new, tender roots are disturbed the better. Some containers, such as peat pots, paper pots, and soil blocks can go right into the garden with the plant during transplanting. Other pots must be slipped off the root ball before planting. Another consideration in choosing containers is bench space. Square or rectangular containers make better use of bench space than round containers. Want to recycle as you start the seedlings? Milk cartons and plastic pop bottles can also be cut down and recycled for use in seeding if drainage holes are made in the bottom of each container. To reuse any previously used container- wash them, then dip them in a solution of 1 cup bleach and 9 cups water.

Soil
Your growing media should be porous, with good air spaces and allow good water drainage. Don't use plain garden soil to start seedlings, it becomes a hard mass that is difficult for delicate seedlings to grow in. One or more of the following products either alone or in a mixture works well; vermiculite, peat moss, perlite or compost. Moisten the planting mix before filling the containers, especially if using peat moss. This makes the media easier to handle and easier to water after seeding. One good soil mix to try is 1 part commercial potting soil, 1 part vermicullite or perlite, 1 part peat moss and 1 tablespoon of bonemeal per quart of soil mix.

Planting & Germination
Plant 2-3 seeds in each pot (you will snip off the weaker seedlings later), according to the directions on the seed package regarding depth. If the seeds require light to germinate, like begonia, impatiens, petunia or snapdragon, then do not cover them with soil just gently pat the surface of the media so the seeds have good contact with the media surface. Be sure to label each type of plant so that no mix-ups occur. After seeding, set the pots in a shallow container of water and let the planting media soak up the water until the surface looks moist. This will prevent the seeds from being washed away at the first watering. After the initial watering, use a large round nozzle on a watering can to apply a gentle stream of water to the seedlings.

Cover the containers with newspaper initially to help preserve moisture. If the seeds need light for germination, a clear plastic wrap can be used in place of newspaper. Check the pots daily for the first signs of germination and remove the newspaper or plastic immediately after germination has started. Until then keep the soil moist, but not waterlogged and temperatures at 72-75 degrees Fahrenheit. 

Light Requirements
As soon as new seedlings begin to emerge from the soil, they need to receive good, strong light. Sixteen hours of light is ideal. More than sixteen hours of light is OK, but no additional benefits will be seen in the plants. Plants that do not receive enough light, or strong enough light, will become tall, thin, leggy and pale green. Ideally your plants should be short, stocky and dark green. This can be accomplished with a combination of good light and cool temperatures.

Winter daylight hours will only provide a portion of the light your plants need. Grow-lights can be used to extend the "daylight" your plants receive or intensify the quality of light, but they can be expensive. Fluorescent lights and cool-white fluorescent lights will also produce good plants and are less expensive. Incandescent light bulbs do not work as well. Plants can be grown in windowsills, but keep in mind that the air next to the window may be too cold for new plants especially at night. Pulling a shade down between the window and the plants at night or placing a piece of cardboard over the window will help to protect your plants. The plants should also be rotated or turned continually so that all receive the same amount of light and don't start to lean towards the light source.

Temperature & Watering
After germination, your plants require daytime temperatures of about 65-70 degrees Fahrenheit and nighttime temperatures about 10 degrees lower. Lower temperatures will help to produce shorter, stockier plants; temperatures above 75 degrees will tend to produce weak, spindly plants. The 10-degree nighttime temperature difference is also very important in producing quality transplants.

Indoor humidity levels during the winter are very low and can quickly pull moisture away from your seedlings. Provide the plants with a steady supply of water, allowing them to dry out partially between waterings. Use lukewarm water and water delicate plants from the bottom by placing the containers in a tray of water and allowing it to be pulled up into the container.

Fertilization
Seedlings can be damaged by fertilizer applied during the seeding process or before they have produced their first true leaves. "True leaves" are leaves that look like miniature replicas of the mature plant's leaves. The first set of true leaves is produced after the "seed leaves"; the first two leaves the seedling produces. Use a balanced fertilizer at half strength for the first 3 weeks, applied once a week. After that, use the fertilizer full strength, applied every 10-14 days.

Transplanting
If the plants were seeded into a flat instead of individual containers, they should be transplanted when the first pair of true leaves appears, giving them enough space to develop properly. Handle the seedlings gently by the leaves and not by the stem. Use a knife or wooden plant label to gently ease the seedlings apart, damaging the roots as little as possible. A 2-4" pot is big enough to grow most seedlings suitable for planting in the garden. Fill the containers with a commercial soil-less potting media and punch a hole in the media in which to place the plant. Water the seedlings immediately after transplanting, and continue to care for them as usual until 2 weeks before planting in the garden.

Preparing for the Garden
Hardening off is a process that causes a change in the quality of growth the seedlings produce. It is accomplished by gradually changing the environmental conditions around the seedlings from the high humidity and warm temperatures they have been accustomed to indoors, to the lower humidity levels and colder temperatures they will experience once planted outside. If plants are not hardened off and are placed directly in the garden from the greenhouse or home, they could be severely affected. Sunburn, wind desiccation, cold injury and death are just a few of the ill affects the seedlings would experience. Hardening off makes the plants stronger, more cold tolerant and able to withstand outside conditions.

Hardening off should be started at least 2 weeks before the plants are scheduled to be planted in the garden. If possible, plants should be moved to an area with 45 to 50° F temperature indoors or outdoors in a shady location protected from strong winds. A cold frame is excellent for this purpose. When put outdoors the plants should be shaded then gradually moved into stronger sunlight. Each day, gradually increase the length or quality of sun exposure. Don't put tender seedlings outdoors on windy days or when temperatures are below 45° F. Even cold-hardy plants like cabbage can be hurt if exposed to freezing temperatures before they are hardened off. After proper hardening, however, they can be planted outdoors and light frost will not damage them. Gradually reduce the frequency of watering to slow the seedlings' growth, but don't allow the plants to wilt.

A seedling that is ready to be transplanted into the garden should be 4-6" tall and have 2-4 pairs of true leaves. It should be strong, stocky and a good dark green color.