Vegetable Gardening (90 page)
4. Water the seeds gently with a mister or spray bottle.
A stronger stream of water can wash seeds into one section of the container or move them too deeply into the soil.
5. Cover the container with a sheet of clear plastic or a plastic bag to hold in the moisture.
If necessary, use small stakes to prop up the plastic so it doesn't rest on top of the soil.
6. Place the planted containers in a warm spot.
The cooler the temperature, the longer it takes for the plants to emerge, so keep 'em warm and toasty! Some warm spots include the top of your refrigerator or near your furnace. But be careful how you water around electrical appliances. You also can buy heating cables or mats that keep the soil warm from below. Follow the package instructions carefully.
7. Check the containers daily to make sure they're still moist but not so wet that they mold.
If you see signs of mold, loosen the cover and let air in; the mold should disappear. You also can hook up a small fan to gently blow across the seedlings (without the plastic cover on), keeping the soil on the dry side. However, be careful not to dry out the seedlings.
8. As soon as you see the first green shoots emerge, remove the plastic cover and move your seedlings to a spot that provides plenty of light and the proper growing conditions for that vegetable.
Refer to the chapter covering that vegetable for information about the proper growing conditions. Until seedlings emerge from the soil, light is unnecessary, with the exception of lettuce and celery seeds. Sow these seeds by lightly pressing them into the soil or covering them very lightly with 1/8 inch of fine potting soil, and then place the containers in a bright spot or position them under a 40-watt incandescent light.
Providing the right amount of light and heat
The light that your young seedlings receive is one of the most important factors in good growth. Placing the seedlings in a south-facing window is one option but not always the best one. Even in a sunny window, plants get only a fraction of the light that they would get outside. Windowsill plants often get tall and spindly because they get too warm in relation to the light they receive.
Try to keep your seedlings on the cool side — 60 to 65 degrees Fahrenheit (75 degrees maximum) — to encourage slower growth; cooler temperatures give you sturdy, stocky plants that transplant well. Although a 10- to 15-degree drop in temperature at night is beneficial, a windowsill can get pretty chilly at night when it's wintry outside. Place a blanket between the plants and the glass to keep windowsill seedlings warm on frosty nights, or move plants away from the window at night.
Growing seedlings under fluorescent lights is a good way to keep light-hungry plants happy. Ordinary cool-white, 40-watt fluorescent bulbs are fine for starting seedlings. If possible, set up your lights near a window so the plants can receive both natural and artificial light. The more expensive grow lights that you can purchase at a nursery or through a mail-order seed catalog produce the broader spectrum light that plants need for flowering and fruiting (although your seedlings will be in the garden before they're ready to flower).
No matter what kind of light you have, use one set of lights (usually 2 bulbs to a set) for every 1-foot-width of seedling-growing area and keep the bulbs 2 to 4 inches from the tops of the seedlings at all times. Keep the lights on for no more than 16 hours per day so the plants can get their natural rest period. Inexpensive timers that turn the lights on and off automatically are available at nurseries and hardware stores.
Watering your seedlings
Water fragile seedlings carefully, or you risk uprooting them. Mist them with a gentle spray, or water them from the bottom by setting your container in a pan of water just long enough for the soil surface to wet (keeping them in water longer than this can damage the plants' roots). After the surface is wet, remove the container from the water and let it drain. Keep the soil surface lightly moist but not soggy. Always water with lukewarm water, and try to do so early in the morning, if possible. This way the foliage can dry off quickly during the day to avoid disease problems.
As your plants get sturdier, you can water with a sprinkling can that has a
rose,
a nozzle that breaks the water into many fine streams. After the plants grow their first set of true leaves (the first leaves to open as the seed germinates are called
seedling leaves,
and the next set are
true leaves
) and have a bigger root system, let the soil dry out slightly between waterings.
Give the plants enough water at one time so that some of it runs out the drainage holes in the bottom of the container, but never leave the container sitting in water. Overwatering promotes damping-off disease (see the sidebar "Dealing with damping off") and decreases the amount of air in the soil, resulting in a weaker root system.
With soilless mixes, you may have a difficult time deciding when to water, because the soil looks dry on the surface even though plenty of moisture is still present. To check whether the soil has moisture, take a small amount of soil off the top 1/2 inch of mix and squeeze it between your fingers. If you can squeeze out any water, hold off watering. The difference in a container's weight when the soil is moist compared to when it's dry can also indicate when to water. Dry soil is very light. Finally, wilted seedlings also are a sure sign that you've waited too long to water (unless, of course, your plants have damping off).
Certain types of containers require more frequent watering. For example, soil in clay pots dries out faster than soil in plastic pots. Peat pots dry out fast and are difficult to rewet. Try putting your peat pots or growing-cubes in a tray and packing moist peat moss between them to keep them from drying out too quickly.
Self-watering seed starting kits that reduce the need for checking your seedlings daily for dryness are now available. These kits have a reservoir of water in the bottom of the tray that wicks into the pots when the soil is dry. See the appendix for companies carrying seed starting supplies.
Thinning and transplanting indoors
After seedlings develop their first set of true leaves (or when onions or leeks, which send up a single blade, are 2 inches tall), you need to thin them or move them from shallow flats to larger quarters. Thinning is an important step, and timing is crucial. If you let your seedlings grow too large in a small container, their growth is stunted. And if you don't space them out at all, you end up with weak plants.