February 7, 2001
Stillwater Gazette
Betsy Halden

A fresh start: Starting seeds

It is a treat to sit down and look at the seed catalogues which are arriving daily. I like to see the new varieties of annuals and perennials, many with exotic colors and names to match. I like to look at the pictures of the vegetables, especially the tomatoes, and I wonder if they could really be much better than the ones we grew last season.

As the gardening season approaches here are some suggestions which should help in raising strong healthy plants for enjoyment during the summer growing season.

Seeds are amazing. Each seed is an embryo which comes pre-packaged with a food supply and the vital genetic information needed to become a plant like its parents. Seeds exist in a state of dormancy, absorbing oxygen, giving off carbon dioxide, and slowly using up stored food reserves. During this process each seed continually monitors the external environment and waits for ideal conditions. When the ideal conditions occur, the seed breaks dormancy and germinates. The seedling gathers energy through its leaves by the process of photosynthesis and absorbs nutrients and water from the soil through the roots. As gardeners we can provide the optimal environment for germination and seedling growth.

If you are selecting seeds or plants from a catalogue it is good to remember we are in United States Department of Agriculture (USDA) Zone 4. 4a or 3b, depending on how far north in the county you live, and on the microclimates surrounding your garden. We also have, conservatively, about 110 days in our growing season. Plants grown for Zone 7 and for areas where there are 150 days in the growing season, will probably not do well here. However, I do know gardeners who have had Zone 5 plants live for a number of seasons. Gardeners can experiment with what will grow in their garden.

To germinate seeds indoors, select a well-drained potting medium designed specifically for germinating seeds. Potting soils are readily available at local and area gardening stores. Select clean containers with drainage holes in the bottom. Wash used containers with warm soapy water and rinse with a dilute bleach solution (1 part bleach to 9 parts water). Slightly overfill containers with the potting soil and tap bottom and sides to encourage even settling. Create a level surface on top of the container by scraping off excess soil with a board or a knife. Do not pres or compact the sol which will make it harder for the seeds to get started. Some gardeners will lightly firm the soil with a board to create a level surface. Moisten the soil either by watering carefully from the top or letting the water soak up through the bottom. Allow excess water to drain away.

Seeds require a certain temperature in order to germinate. Each plant has a specific optimum and a range within which germination will occur. The closer temperature is to optimum the quicker seed germination will occur. Most seeds germinate when the soil temperature is between 68 and 86 F. Once germination occurs, the optimum growing temperature for the seedling is about 10 F cooler than the optimum germination temperature.

Moisture is critical for germinating seeds. Seeds like a moist but not soggy environment. Seeds require oxygen and if kept in a waterlogged state they may rot. On the other hand, if the soil dries out, the seed will lose whatever water it has absorbed and will die. Finding the middle ground can be difficult and comes easier with practice. After sowing the seeds, mist the tray with water and cover with plastic wrap, a plastic bag, glass or plexiglass to seal in moisture. As soon as seed germinates, remove the covering. Check the seedling twice a day for moisture. Allow the soil surface to dry between waterings. Ventilation and air circulation are also important to discourage damping off diseases.

Some seeds need light in order to geminate, but many do not. Seed packages will usually indicate what your seed collection specifically needs. It is important to follow the directions given on the seed package for planting depth. In addition to light requirements, seeds that are planted too deep will not have enough stored energy to reach the soil surface and may die in the process. After germination occurs, seedling require about 12 to 16 hours of light a day. Intense light is necessary to prevent spindly or leggy seedlings. If you are growing under lights, make sure the light source is 4 to 6 inches above the plants. In they are in a sunny window, turn the seedlings regularly to avoid leaning.

If you are sowing seeds in flats, transplant individual seedling into cell packs when the first true leaves appear or when the seedlings are large enough to handle.

Seedlings started indoors should be fertilized regularly with a dilute (1/4 strength) water soluble fertilizer. This will help to produce stockier transplants provided the seedlings have had enough light.

Before planting them in the garden, gradually acclimate the transplants to the outdoors. Start by putting them outside on cloudy days or in a shaded location. After a few days work them into more light and exposure. Remember to bring the plants in at night if the nighttime temperatures dip below 32 F.

When danger of frost is past, usually between May 15 and May 30, you can put the young plants in the garden. Overcast skies or late afternoon provide the best conditions for planting. Water immediately after transplanting. If plants wilt, provide some protection with an open milk carton or a board for a few days

Betsy Halden is a Master Gardener with the University of Minnesota Extension Service. University of Minnesota Extension Service materials were consulted in the preparation of this column. You can reach Betsy Halden at eahalden@comcast.net