Seedling Guide from Mulhalls Nursery in Omaha, NE

Starting Plants from Seeds
Growing plants from seeds started indoors can be rewarding and cost effective. Many annuals, perennials, vegetables and herbs can be started 6 to 12 weeks prior to planting in the garden. Do not attempt to save seeds from hybrid plants you may have grown in your garden. The results will be disappointing in quality, color, and size of bloom or fruit.

Containers for Sowing Seeds
Containers for starting seeds should be clean, sturdy, and fit into the space available for growing plants in the home.
Clay and plastic pots are both excellent for growing transplants. Seeds may be planted directly into them.

Peat pots: These popular pots are made from peat or paper waste fibers. They are porous, and provide excellent drainage and air movement. The entire pot can be planted, so there is minimum root disturbance at planting time.

Compressed Peat Pellets: Expandable Jiffy 7 peat pellets are about the size of a silver dollar, but somewhat thicker. When placed in water, they swell to form a cylindrical container filled with peat moss, ready for seeding or transplanting. Use the pellets in trays so that they are easily watered and held upright. After plants are hardened off , peat pellets can be planted direcctly into the garden.


Soil Mixes and Other Growing MediaThe medium used for starting seed should be loose, well drained, and of fine texture.
Milled Sphagnum Moss: Can be used by itself or as top dressing to cut down on damping off.


Growing SeedlingsAfter seeds have germinated, they must be promptly given the best possible growing conditions to ensure stocky vigorous plants for outdoor planting. Cultural requirements must be considered carefully.
Light: After germination seedlings must receive bright light. Place them in a bright, south window if possible. If a large, bright window is not available, place the flats under fluorescent or grow lights. Place the seedlings about 6 inches from the tubes, and keep lights on for 14 to 16 hours each day. As seedlings grow, the light fixture may need to be raised to prevent leaf burn.

Temperature: Most annual plants and vegetables prefer night temperatures between 60 and 65ºF. Day temperatures may run about 10 degrees higher. If temperatures are warmer than this, leggy plants result. Cool season vegetable crops and a few flowers prefer night temperatures no higher than 55ºF, and day temperatures near 65.

Moisture and watering: Keep plants consistantly moist by misting and watering but never wet.

Fertilization: Seedlings planted in soil free mixes need prompt and regular fertilization. Use a soluble plant fertilizer. Young, tender seedlings are easily damaged by too much fertilzer. Apply fertilizer at about half of the recommended rate a few days after seedlings have germinated. After that, fertilize at 2-week intervals with the dilution recommended by the manufacturer.

Damping Off: When seedlings fall over at the soil line, they are being attacked by a fungus disease known as Damping-off. If only a few seedlings are attacked, dig out and discard the infected plants. Drench the entire soil mass with a fungicide solution, mixed according to the directions on the label. High temperature, poor light and excess moisture weaken plants and stimulate the spread of the disease. The best control is cleanliness and prompt action when the disease appears.


Moving Plants Outdoors-Hardening Off
Plants which have been growing indoors cannot be planted abruptly into the garden without injury. To prevent any damage, seedlings should be hardened off before planting outdoors.
This process should be started at least 2 weeks before planting into the garden. If possible, plants should be moved to cooler temperatures outdoors in a shady location. A cold-frame is excellent for this purpose. When first put outdoors, keep plants in the shade, but gradually move them into sunlight for short periods each day. Gradually increase the length of exposure. Do not put tender seedlings outdoors on windy days, or when temperatures are below 55ºF. Reduce the frequency of watering to slow growth but don't allow plants to wilt. Even cold hardy plants such as cabbage and pansies will be hurt if exposed to freezing temperatures before they have hardened off. After proper hardening, however, they can be planted outdoors, and light frosts will not damage them.