Grow Your Garden From Seeds

By Barbara Perry Lawton

(This article first appeared in The Gateway Gardener January/February 2006 issue.)
a picture of sunflower seedlings

Sunflower seedlings

Many gardeners have never tried growing annuals, vegetables and even perennials from seed, believing the process too daunting a task. Yet there are some good arguments for starting your garden from seeds. Plant propagation from seeds is, to be sure, the most economical method. Often growing from seeds is the only way to get many new introductions or rare and unusual plants. Further, garden centers and nurseries could not possible carry the wide variety of plants you can find at seed displays and in seed catalogs.

In addition, many garden plants, including radishes, beans, peas, leaf lettuce, dill and basil, are so easy to grow from seeds that there’s no reason to choose another means of propagation. Then there are those ornamentals and vegetables that will flower sooner if given an early start indoors each spring. These include many favorite annuals such as marigolds, zinnias, snapdragons and bachelor’s buttons. Tomatoes, peppers and eggplants will bear fruit earlier if started from seed indoors. You can even start cucumbers and melons indoors from seeds if you grow them in individual pots to keep from disturbing sensitive roots.

First Select the Seeds
Buying seeds of the current year that are produced by reputable seed houses pays off. These seeds will be of high quality—the seed companies want you to succeed. And no less important is that the back of each seed packet will contain the growing information, such as when to plant, how to plant, how long it will take to flower or fruit, and many other bits of information guaranteed to make you a better gardener. After sowing seeds, keep the seed packet in case you need information later.

Containers and Moisture
Containers should have drain holes. Punch holes every few inches if they are not already there. You can use anything from foil roasting pans to commercial nursery flats. For small numbers of seeds, use cottage cheese containers or even foam plastic cups. Place containers on drain pans or put them where water will not harm the surface underneath. To hold in the moisture, cover the containers with clear plastic wrap until the seeds have germinated and begin to push at the cover. You can prop up the plastic cover with pencils or some other handy tool. Keep the medium moist but not soggy. Apply water gently. Label the growing containers so that you don’t forget what you have planted. (A failing that most of us have made at one time or another—a failing that results in “plant roulette.”)

Growing Medium
For best results, a commercial medium that has been formulated for starting seeds would be best. These are fine-textured soilless mixes of peat moss or sphagnum moss mixed with horticultural vermiculite or perlite. To further diminish the chances of having seedlings keel over from the fungal diseases we call damp-off, do not over-crowd seedlings, do not over-water and provide good air circulation. Before sowing the seeds, drench the medium, and then let it drain thoroughly.

Soil Temperature
A home kept at a comfortable temperature may provide the right temperature for most seeds to germinate. Again, read the back of the seed packet for information on soil temperature. Some seeds need a cool temperature to germinate—55 to 60 degrees Fahrenheit—while others require a medium temperature of 70 or above. The temperature of the medium will not be the same as the temperature of the air. Gentle bottom heat is easy with the use of modern heating trays or mats that have built-in thermostats. A soil thermometer is handy for double-checking the warmth of the medium.

The final needed environmental factor is light. Some seeds need to have light in order to germinate while others do not. Again, read the seed packet for information. Once the seeds germinate, the tiny plants must have light. Many gardeners set up benches under fluorescent lights to start their plants early. A spot near a bright window also may be adequate. Fluorescent bulbs can boost the natural light if it seems inadequate.

Once the seedlings have developed four true leaves, you can thin them or transplant them into pots or larger flats. Water the medium thoroughly and also water the pots the plants will go into. Use a pencil, spoon handle or table fork to “prick” the plants from the original container. Handle seedlings by their leaves, not by their stems. Work quickly so that they aren’t in the open air very long. Once transplanted, begin using a dilute solution (about one half the recommended rate) of liquid fertilizer weekly.

Planting into the Garden
Once spring weather warms up, begin to harden off the seedlings by exposing them to outdoor conditions gradually before planting them into ornamental containers or the garden. A soil thermometer will help you know when garden beds are warm enough to plant. Soil temperatures need only be 40°F in order to plant radishes and peas, a minimum of 50°F degrees for tomatoes and corn, and at least 60ºF for peppers, beans, cucumbers and squash.

Barbara Perry Lawton is a writer, author, speaker and photographer. She has served as manager of publications for Missouri Botanical Garden and as weekly garden columnist for the St. Louis Post-Dispatch. The author of a number of gardening and natural history books, and contributor to many periodicals, she has earned regional and national honors for her writing and photography. Barbara is also a Master Gardener and volunteers at the Missouri Botanical Garden in St. Louis, MO.