Tips and Tricks for Sprouting Seeds Indoors

Get that garden started!

With a simple set-up and a little know-how, anyone can get the hang of sprouting seeds indoors. To help out, we’ve dug up advice from old hands on the best practices for getting little plants going.

Keep lights close

Plant gurus emphasize that there’s no need to buy expensive “grow” lights for sprouting seeds. In fact, many gardeners swear by low-cost fluorescent shop lights. The tubes should be tagged T-12 or T-8, and the cool white 40-watts are said to work well. Shop lights are often suspended from open-link chains on “S” hooks so that the lights can be raised as plants grow.

Don’t raise the tubes too much! Lights should be kept close to the sprouted plants, lest seedlings become spindly. Burpee recommends a distance of 3 to 4 inches, while some hobbyists narrow the gap to 2 or less. Either way, we’re talking close, and lights should stay on for 16 to 18 hours a day.

Bottoms up

There is such a thing as too much water, so don’t let soil stay soggy. And when you water, bottom water, experts say, pouring the liquid into an unperforated tray or pan and allowing the soil to take it up. Burpee warns specifically against pouring water over the planting medium, which can dislodge delicate seedlings and foster disease.

But what should I start indoors?

Trying to decide where to focus your indoor-growing efforts? Which seeds are best sown outdoors and which need an early start?

In general, look at how manageable the seed size is — very tiny seeds are much easier to handle indoors — and the days to maturity specified for each variety of plant. Hot-weather lovers that need a long growing season benefit from an early start even in warm climates, so it makes sense to set out tomato, pepper and eggplant seedlings rather than direct-sow no matter where you live. On the flower front, snapdragons, pansies and zinnias, among others, appreciate a leg up.

Those handy little seed packets detail a variety’s recommended USDA growing zone, disease resistance and light requirements, along with days to maturity. Steve Albert, author of “The Kitchen Garden Grower’s Guide,” says the trick here lies in realizing that for long-season veggies such as tomatoes, the “days” number references time to harvest for a transplanted young plant rather than for a sown seed.

Getting started with starting

For seed-starting newbies itching to get growing, the basic supplies are easy to buy or salvage. Your seedlings’ requirements will demand careful consideration, however, and you’ll need to bring your own persistence and daily attention to the whole undertaking. If you are new to indoor starting, seed-business giant Burpee recommends beginning with only a couple dozen plants.

Here’s a look at the basics needed beyond the tiny bundles of life called seeds.

Space, light and warmth

A sunny windowsill might seem perfect for plant germination, but many seasoned seed-starters vote in favor of setting up fluorescent lights in an unused corner, spare room or basement. Avoid locating seed trays in unheated spots like garages — the space needs to stay near comfortable room temperature, around 65 degrees or up. To give germination an extra nudge, buy a heating mat made for growing setups.

Containers

Whether found or bought, a plant container can be most anything that will hold enough soil. Common choices include peat pots or expanding peat pellets, plastic pots and open “flats,” which are large, perforated plastic trays. Some gardeners plant first in flats, then transfer sprouts to individual containers. You’ll also need unperforated trays or pans to hold the planting containers and their water.

To go the re-use route now or in the future, save the cell-packs and plastic containers from nursery purchases, or collect yogurt containers, paper cups and other “found” items. Just be sure to clean them thoroughly, and punch a few holes in the bottoms for drainage.

Soil

We’re not talking dirt, but a special growing medium that’s sterile and airy, preferably a potting mix sold specifically for seed starting. When it comes time to use the soil, dampen it before filling containers — it should be moist but not soggy. Fill containers to about an inch below the tops and tap to settle the soil. Voila! You’re ready to plant.

Added fertilizer isn't required at planting because seeds contain the nutrients a seedling needs. Later, as seedlings develop and gain true leaves, you can begin feeding them diluted liquid fertilizer or fish emulsion.