Give seedlings a good start

Sowing a packet of seeds in the dead of winter is uplifting—the smell of damp soil fills the air, and spring doesn’t seem so far off. But in reality, spring may be months away and until it’s reliably warm in the garden, many plants started from seed need to be cared for indoors. Here you’ll need to provide them with an environment where they can flourish.

I raise seedlings on a three-tiered stand with fluorescent bulbs hung by chains so the lights can be raised as the seedlings grow. Keeping the lights an inch or two  above the plants makes them strong and stocky. Without a good light source, phototropism will cause seedlings to reach for light and become weak and spindly.

Once seedlings have one or two sets of true leaves, it’s time to start fertilizing. Many gardeners use a weak solution of water-soluble fertilizer like Miracle-Gro; fish-emulsion or seaweed products are good organic alternatives. Either way, regular feedings will encourage strong growth. I like to use a liquid fertilizer with more phosphorus (the middle number of the N-P-K formula) than nitrogen or potassium. The additional phosphorous promotes strong root development. My pots sit in plastic trays so I can water and fertilize from below.

Pot on, pinch back, and toughen them up

Whether you start your own seeds, or buy seedlings at a local garden center or by mail, chances are they’ll need to be potted on before you can get them in the ground. This is especially true of those crops that can’t be planted until the soil has warmed up, like tomatoes and peppers. Cramped, crowded roots will send seedlings into quick decline. So move them up to larger pots where root growth can continue to pro­gress with leaf development. Three- or 4-inch pots are a good size for little plants that have outgrown six-packs. If you’re separating seedlings started in a flat, gently tease apart roots with your fingers or a pencil. Be sure to label the transplants.

Given good conditions, seedlings grow quickly. The plant hormone auxin is present in a seedling’s terminal bud and assists in growth by making cell walls more elastic. Auxin, however, suppresses growth at a seedling’s lower lateral buds. If you pinch out the terminal bud, and thus the auxin, side shoots will grow. This results in bushy, many-branched plants and eventually more flowers and fruit. Once seed­lings are 3 or 4 inches tall with a good supply of true leaves, I pinch them back. You can use scissors or pruning shears, but thumb and forefinger work just fine.

While your seedlings are growing indoors, toughen them up by man-handling them a bit. Regularly run your hand over the tops of the little plants. This brushing or stroking will help ready the seedlings for the harsh outdoors.

Plant on an overcast day

A gloomy, cloudy day is the best time to plant seedlings in the garden. If it’s lightly drizzling, all the better. But if the forecast is for fair weather, avoid planting seed­lings in the hot, mid-day sun. Get an early start in the morning, or wait and set a few plants in the ground at the end of the day.

Slip the seedling out of its pot and gently loosen the roots if they’ve become pot-bound. If your seedling has been growing in a peat pot, peel away as much of the pot as possible without disturbing the root ball. It’s especially important to remove the top of the peat pot to prevent it from wicking moisture away from the plant’s roots once it’s in the ground.

Give seedlings some protection from sun and wind for a few days after they’ve been transplanted. Overturned pots or baskets, row covers, or shade cloth will shelter them temporarily while roots settle in. Water the seedlings every third day, or more often if it’s unusually hot, until they become established.

Provide additional protection from insect predators, depending on the plant. Cutworm collars are advisable for most seedlings. Cole crops are vulnerable to the larvae of cabbage butterflies and other moths, so many gardeners cover them with floating row covers to prevent the moths from laying eggs.

Be on the lookout for slugs and remove debris that gives them a place to hide. If you suspect slug damage, check the beds at night with a flashlight and hand pick the culprits.

It won’t be long until seedlings grow into big, robust plants. But in the meantime, a watchful eye and some doting care will help seedlings adjust to the wild world of the garden.

Learn more …

For links to articles, blog posts, and videos on starting vegetable and flower seeds, see All About Starting Seeds .