Growing Vegetable Transplants: Lights, Containers, Media, Seed

by Franklin D. Schales.

Franklin D. Schales is an Associate Professor of Horticulture at the University of Maryland, Salisbury.

Most experts on vegetable plants agree that the ideal vegetable transplant should be stocky, have good color, be disease-free, and be at the proper stage of development for best growth when set in the garden.

How can you grow such a transplant? Ideally, the best place to grow vegetable plants is in a greenhouse equipped with automatic controls for heating and ventilating. There are several kinds of hobby-size greenhouses available from commercial sources. If you prefer to build your own, plans are available from several State Agricultural Experiment Stations.

Hot beds and cold frames also are suitable for plant growing, but require more attention than greenhouses since they are not constructed to allow for automatic ventilation. Also it is more difficult to work in these structures than in a greenhouse.

It is possible though more difficult to grow vegetable transplants indoors if you do not have a greenhouse, hot bed, or cold frame. The best place to grow plants indoors, if you are depending on sunshine as the only source of light, would be in a large window facing south or southwest. This should be in a room where it is possible to have the night temperature no higher than 60 F. The window should not be shaded by trees or otherwise since the plants will require all the light that reaches them. High night temperatures will result in tall, soft, and spindling plants.

Cool white fluorescent lamps provide good supplementary light for plants. These are available in prewired lamps and ballasts in various sizes and types. Best illumination is obtained if the lamps are spaced 2 inches apart, center to center. Since fluorescent tubes are relatively cool they may be placed close to plants without danger of burning them. An adjustable support for the lamps makes it possible to adjust lamps to differing plant heights.

If you construct a chamber for growing plants, all inside surfaces should be painted white or made of reflective materials to increase the light available.

Length of lighting each day should be controlled manually or by using a time clock. Usually 12 to 16 hours light each day is sufficient for growing plants.

Vegetables for Transplanting

Many kinds of vegetables can be satisfactorily transplanted. Usually these are classified as being either warm season or cool season vegetables, depending on tolerance to cold weather.

All the cucurbits which include cucumber, squash, watermelon, and muskmelon are warm season vegetables. For satisfactory results with them, plant the seed in containers that will be set in the garden without disturbing the plant's root system.

Other warm season vegetables such as pepper, eggplant, and tomato may be transplanted bare-root. However, it is also best if these are grown in a type of container that will allow transplanting with the root ball essentially intact.

Cool season vegetables include cabbage, cauliflower, brussels sprouts, broccoli, lettuce, and onion. These may be transplanted in containers or bare-root.

Containers

Those wishing to grow vegetable transplants have a wide choice of containers to choose from. Compressed peat pellets, peat pots, plastic pots and fiber blocks are some of the types available for growing single plants in. Multi-plant containers include various size cell packs and open containers of various sizes in which more than one plant can be grown.

With most of the containers available, choose the larger sizes in the single-plant growing containers and don't crowd plants too close in the multi-plant containers. As a general rule, allow 6 to 9 square inches per plant for most vegetable transplants.

Tomato sprout emerging from a starter container.

Compressed peat pellets will not allow this much space if placed against each other in the flat. However, they can be spaced further apart, and are satisfactory if the plants are set in the garden before they become too large.

The space between the peat pellets should be filled with peat moss or a soilless growing medium.

If peat pots are used, when the plant is set in the garden be sure that the entire pot is buried. If the top of the pot is exposed to air and sunlight, it will act as a wick, removing moisture from around the plant roots. Sometimes it's a good idea to break the bottom out of peat pots when setting plants in the garden.

Remove plants from plastic pots or trays before putting them in the garden. If the plant has a very extensive root development, with almost a solid mass of roots, you should slightly break the root ball apart, or make several shallow cuts with a knife along the edge of the root ball. This will stimulate new root development into the soil after the plants are set.

Other plant-growing containers are available such as milk cartons and clay pots, but the types previously discussed are either more readily available or have proven more satisfactory for most growers.