Starting your plant seeds indoors is rewarding and economical. Most flower and vegetable seeds do not require special treatment to achieve good germination. First, read the seed packet for sowing dates, time to germination, and other information specific to that plant. Some seeds need light (press seed on top of soil) or darkness (plant to depth of seed size). Some very small seeds, such as begonias and petunias, are often available pelleted. Each seed is coated to make handling and germination easier.
Containers- Almost any container will do if it’s clean and about 3 inches deep. Yogurt cups, Styrofoam coffee cups, margarine cups are great choices, as well as peat pots and discs (which expand with the addition of water). Clean thoroughly and punch holes in the bottom for drainage. Flats may be used to start multiple seeds. Fill the cups with a commercial soil-less mix for best results. Do not use garden soil- it is usually too heavy and provides poor drainage, and it adds the risk of introducing weeds or disease organisms.
Temperature- Most seeds are genetically programmed to germinate in warm soil (70-75 degrees). Seed trays can be warmed on top of a water heater or refrigerator; most do not need light until the seed leaves emerge. Many gardeners use heating mats or cables under the containers to deliver a consistent temperature.
Moisture and Light- Seeds need to be constantly moist in order to germinate. Never let the growing medium dry out, nor let it get too wet! Moisten the growing medium thoroughly before sowing. Once the seeds have been sown, you may place a humidity dome or plastic wrap over your container. Check the moisture level daily; water from the bottom if possible and use tepid water. Seedlings need 14-16 hours of light and eight hours of darkness to process their food and grow. Windowsills rarely provide sufficient light, so most gardeners utilize fluorescent lighting or grow lights. The tops of your plants should be as two to four inches below the lights at all times. You may hang the lights on chains that can be raised as the seedlings grow. Cool light provides light in the blue/green range which encourages leaf growth, and warm light provides light in the red range which encourages flowering. Grow lights combine the two ranges. Replace bulbs annually as they begin to lose their intensity over several months.
Thinning- After the first set of “true” leaves appear some thinning may be necessary to provide sufficient space for the plants to prosper. Cut off the weakest and spindliest seedlings at soil level to allow the other seedlings to grow stronger. Seedlings grown in seed flats need to be transplanted into individual containers when they have four “true” leaves. Place them slightly deeper than in their flats, gently firm the soil around the seedlings, and water immediately.
If your soil mix does not contain a starter fertilizer, fertilize weekly with a well-balanced fertilizer at half strength to promote healthy growth. If seedlings begin to look leggy, pinch back the growing tips to promote more branching and increase the light intensity. In a few weeks you’ll have compact bushy plants ready to harden off for transplanting into your spring garden. To harden your seedlings, gradually expose
