Growing plants from seed is rewarding and a lot of fun. Sowing vegetables and bedding plant seeds gives us the opportunity to plant more varieties than what may be available as starters in May. A few seeds that can and should be started indoors early are the following: Tomatoes, peppers, eggplant, broccoli, brussel sprouts, cabbage and cauliflower.
A few supplies will be needed. They include a light source, seed starting soilless mix and containers, labels, plastic wrap, bottom heat, spray bottle and the seeds.
Growing plants from seed requires a reliable light source and bottom heat. A windowsill may not be an ideal location. Windowsills can be the coldest place in the house, especially at night, and then the hottest during the day. Sunlight in Ohio gains strength from mid-March through May.
Sunlight through a window is relatively weak compared to artificial light sources kept close to the plants. There are also many cloudy days of very low light levels during spring. It is much better to grow seedlings under lights than to rely solely on natural light.
An inexpensive set up is to hang a fixture with two cool white, fluorescent tubes. If you have a smaller area or are growing a few seedlings, then the compact fluorescent bulbs will also work. The newer light emitting diode or LED bulbs are also suitable for starting seeds. Install adjustable chains to keep light from 2 to 4 inches above the seedlings.
If you are after the best lights for producing seedlings, look for LEDs and fluorescent lights that include the cooler blue spectrum; these will often be marked as 5000-6500K (Kelvin). These bulbs are usually more expensive than the cool, white type. Plants need approximately 14 to 16 hours of light per day, utilizing a timer is an easy way to control the lights.
Seeds can germinate quicker and healthier when supplied with warm soil, obtained through a bottom heat source. Indoor soil is normally 5 degrees Fahrenheit cooler than the air temperature. For seed germination, ideal temperatures should range from 65 to 80˚F. consistent soil temperatures ; therefore, use of heat mats, with a timer, are not recommended. Electric heating mats specifically for seed starting are available from many garden centers and online suppliers.
Start seeds in new small, individual containers. It is best to use divided containers with a single seedling per container, rather than filling a larger container with potting mix and sowing many seeds, because the seedlings’ roots will grow into each other and are likely to be injured later during transplanting. Ideas for containers include plastic cell flats and egg cartons. Make sure they have drain holes for excess water to escape.
Soilless seed-starting mixes are usually composed of vermiculite and peat, without any true soil, and are recommended. Commercially available, they are sterile, lightweight, and free from weed seeds, with a texture and porosity especially suited to the needs of germinating seeds and tiny seedlings. Fill containers with potting mix, and water the mix before sowing seeds. The potting mix will settle down into the containers. Add more potting mix and water again, until the containers or cells are nearly full.
Sow fresh seeds individually into each container according to seed package directions. If you are unsure about seeding depth, a rule of thumb is to plant a seed four times as deep as its width. Identify each container or tray with a tag. Popsicle sticks work great for this, mark with a permanent marker. If the seed package says seeds need darkness for germination, cover with a few layers of newspaper until seeds sprout. After the seeds have sprouted, carefully remove the newspaper.
Keep the potting mix moist while the seeds are germinating. A spray bottle to water the surface gently without washing the potting mix out of the containers works well. Making a tent using taller popsicle sticks or plastic tags and covering it with plastic wrap will help retain moisture in the soil during the germination process. Remember to remove tent after seeds have germinated.
Seedlings draw energy for germination from nutrients stored in the seed. They do not need fertilizer until after germination and they have several sets of true leaves. Seedlings grown in a soil-less mix will benefit from a weak, general purpose water-soluble fertilizer mixed 1/4 strength. Fertilize only once a week, and water as needed the rest of the week with plain water.
Information for this article obtained from University of Minnesota Extension Fact Sheet Growing Seed indoors and the Old Farmer’s Almanac Planting Calendar for Bowling Green.