Growing seedlings is a big part of the excitement of gardening. When you start your own seeds, nurture, and watch the plants grow to maturity in your garden, you'll be amazed.
Growing your own plants may be the only way to get unusual cultivars for your garden. Plus, it's also much less expensive than buying transplants from the garden center each spring!
Seedlings need more light than adult plants. Ideally, they should get 14 to 16 hours of light every day. Without enough light they become leggy, spindly, and weak.
A windowsill is not the best place for most young plants. In many areas, a windowsill will not get 14 hours of sunlight every day. In others, the sunlight will be too strong and will scorch the emerging plants. If you do raise plants on a windowsill, be sure to rotate them regularly, so they don't grow sideways.
Fluorescent shop lights are a good solution. They can be suspended over the flats about 2 or 3 inches above the new plants and raised as the plants grow larger. Expensive full-spectrum lights are not necessary for growing seedlings, although they are beneficial for adult plants.
Young plants require constant even moisture, and seed flats can dry out quickly. Very young plants should be misted or sprayed lightly, because it is easy to dislodge them from the growing medium. As they develop, switch to bottom watering to encourage their roots to extend downward. Use tepid water, not cold water. If your water source is heavily chlorinated, you may need to purify it before watering.
Most seedlings grow well with a temperature of 60 to 70 degrees during the day and 50 to 60 degrees at night. "Cool weather plants" like it a bit colder after they've gotten two or three inches tall.
Moving air is good for young plants! Air movement strengthens their stems and gets them ready for outdoor breezes. It also keeps pests away and reduces the likelihood of damping off. If the air around your plants is always very still, set up a small fan to improve air circulation.
Pricking Out Seedlings
The first "leaves" that appear after seeds germinate are cotyledons, also called seed leaves. They look like leaves, typically growing in pairs, but they are different from true leaves. True leaves appear a little later.When their first set of real leaves has developed, the new plants will need more space. They're usually two or three inches tall by this time.
If seed was direct sown in the garden, the plants should be thinned by removing some to leave more space for the others. If the seeds were started indoors, the new plants should be removed from the seed tray and placed in individual small pots.
Fill the new pot with moist compost or pre-moistened soil, and make a small hole right in the center. Many gardeners use a pencil to do this.
Gently lift from the seed tray. Handle it carefully to avoid damaging the roots. Drop it in the hole. Add soil and firm it down gently. Try to plant the seedling at the same depth it had in the seed tray.
It's simple to prick out large seedlings. Small ones are easier to handle with a tool - experiment to find out what tool you prefer. Some gardeners use a screwdriver, some use chopsticks, and some like a metal fingernail file.
Really tiny seedlings are often potted in small clumps. Disentangling individual plants would damage their tiny roots.
Lift seedlings by their leaves instead of their stems. At this young age, the stems are very easy to break or bruise. Replant each seedling as soon as you move it out of the seed tray, because the roots will dry out quickly if they are exposed to air.
After the seedlings are in their individual pots, water them gently but thoroughly. Sometimes, a few plants will fall over sideways. Just straighten it up gently and firm the soil around its base.
Now your new plants can grow large and strong until they're ready to be planted in the garden!