Stormi Greener, Star Tribune

Give plants a head start

  • Article by: DEB BROWN
  • Contributing writer
  • January 25, 2011 - 2:58 PM
Starting seeds indoors isn't terribly difficult, but is there any reason to do it? Yes. In fact, there are several:

• You can choose from a wider variety of flowers and vegetables than you'll find at even the best garden centers.

• Seeds are much cheaper than plants, so you can save money, especially if you have a big garden.

• Starting from seed allows you to get a jump on the season. In spring, you'll be able to put out seedlings rather than just sowing seeds.

• You'll experience the sense of accomplishment that comes from nurturing tiny seeds into healthy, productive plants.

• And starting seeds indoors can help banish the winter blues.

You can pick up seeds in plenty of places: catalogs, online and in garden centers. As spring approaches, you'll be able to find seeds at grocery, hardware and building supply stores. Even though seeds will be plentiful, don't buy more than you can use in two or three years. The longer you save them, the less likely they are to germinate.

The right light

Don't be tempted to start seeds using natural light, unless you're home during the day and have the time and patience to move your seedlings from window to window to keep them in bright sunlight. In Minnesota, our days are short and the angle of the sun means that the light coming through most windows is rather weak. Most seedlings that rely on sunlight will grow tall and spindly rather than developing the more compact form they need to thrive when transplanted outdoors.

For good growth, use fluorescent lights to provide the intensity and light spectrum seedlings need. You don't need special plant lights; most standard fluorescent lights will be fine. Position the tubes just 4 to 6 inches above the plants. As the plants grow, you'll need to raise the lights, but keep them 4 to 6 inches above your seedlings. If the lights are too high, the plants will get spindly.

Keep the lights on 12 to 16 hours a day. Putting your lights on an automatic timer will ensure that the seedlings get the light they need every day.

Contain yourself

Garden centers offer a wide variety of containers, some complete with trays meant specifically for seed starting. Containers that are divided into cubicles or cells make for easier transplanting because roots from one seedling won't become entangled with those of its neighbors. Compressed peat containers may be planted directly in the garden, though it's best to score the sides at transplanting, so roots can grow out freely. You can re-use containers from previous years as long as they're clean and free of debris. (Soak them in a 10 percent chlorine bleach solution for 30 minutes, then rinse them well.)

Going to pot

Use a fresh soil-less potting medium, ideally one designed for starting seeds. Fill the containers, then water the mix before planting one seed in each cell. Check the seed packet for planting depth.

Check to see if the seeds require light to germinate. Most don't, so they should be kept out of bright locations until they begin to germinate. (An electrified mat or cable that provides bottom heat will result in faster, more uniform seed germination.)

If your seeds need light, don't plant them too deeply. Place them on top of the potting mix and barely cover them with a little fine vermiculite.

Mist the soil, then cover the entire container with clear plastic. Keep the plastic in place until the seeds sprout. Keep the potting soil evenly moist, but be sure to drain off excess water that collects beneath the containers. Soggy soil can lead to rotting and damping-off disease; it also encourages the presence of fungus gnats.

After seedlings develop several sets of leaves, fertilize them very lightly once a week. Use an all-purpose liquid fertilizer mixed to one-fourth of the strength recommended on the label.

Good timing

Seed packets list the average number of weeks it takes to grow seeds to transplant size. Some seeds (including geraniums and begonias) need more than two months' head start. Others (tomatoes and marigolds) need only four to six weeks.

Don't start your seeds too early. It's best to transplant sturdy, compact plants into the garden rather than larger, more mature ones.

For a good seed-starting primer and a chart on when to start specific seeds, go to

Deb Brown is a garden writer and former extension horticulturist with the University of Minnesota. To ask her a gardening question, call 612-673-7793 and leave a message. She will answer questions in this column only.

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