It’s time to start those seeds! Depending on your climate zone, mid-March to early April is usually prime time for giving your seedlings a head start indoors (unless you live in a warm enough climate to start all your garden seeds directly outdoors).
Before you get started, there are a few basic seed-starting necessities that you will need to have on hand. While there are other items that can make your seed starting experience easier – such as a heat mat, or a soil blocker – the items below are essential for starting seeds successfully.
You can start seeds in almost any kind of container that will hold 1 to 2 inches of starting medium without becoming waterlogged. After seedlings form more roots and develop leaves, though, they grow best in larger individual containers that provide more space for root growth and have holes for drainage.
Flats are large, rectangular containers that hold many seedlings. Many gardeners start their seeds in them, then transplant the seedlings to individual containers after the first true leaves unfold. If you raise lots of seedlings, it’s useful to have interchangeable standard-size flats and inserts. You can buy flats at a garden center, or make your own by constructing a rectangular wooden frame, 3 to 4 inches deep. Nail slats across the bottom, leaving a space of ¼ inch between them for drainage.
Although individual containers dry out faster than flats, they are better for starting seeds because you don’t have to repot as often, so the seedlings’ tender roots are less likely to be damaged by constant handling. Some containers, such as peat pots, paper pots, and soil blocks, go right into the garden with the plant during transplanting so the plants’ roots are never disturbed.
Organic peat pots, made entirely of peat moss, are popular because you can plant them “pot” and all—you don’t have to worry about extracting the seedlings from the containers before you set them in the garden. Also, the peat absorbs excess moisture naturally, so seedlings are less susceptible to damping-off, a fungal disease that often occurs when soil is too soggy. But because peat pots do dry out faster than plastic containers, you’ll need to check their moisture level daily. Also, peat is not a sustainable resource, so the better option is paper pots.
Like peat, paper pots also break down in the soil, allowing you to place them right in the garden, pot and all. They also draw excess water away from the seed-starting medium, although not to the degree that peat does. You can buy pots made from recycled paper or make your own pots from newspaper strips.
2.) A Good Seed-Starting Mix
Seeds contain enough nutrients to nourish themselves, so a seed-starting mix doesn’t have to contain nutrients. But it should provide plenty of air spaces, hold moisture well, and be free of weed seeds and toxic substances. Peat moss, compost, perlite, and milled sphagnum moss—either alone or in combination—are all good materials for starting seeds. Don’t use plain garden soil, though; it hardens into a dense mass that seedling roots can’t penetrate.
When your seedlings have their first set of true leaves, you’ll need to transplant them to a nutrient-rich potting mix. You can either use a commercial mix (check the label to make sure it doesn’t contain a synthetic chemical fertilizer) or make your own. To make a basic mix, try this popular organic potting soil recipe: 1 to 2 parts good-quality garden soil, 1 part builder’s sand or perlite, 1 part compost.
Each component provides specific benefits to plants. Soil contains essential minerals. Sand and perlite assure good drainage. (Perlite, an expanded volcanic rock with many air spaces, will make the mix lighter than if you use sand.) And compost releases nutrients slowly, helps maintain proper soil pH, improves drainage, and holds moisture.
Seedlings need more intense light than full-grown plants. If they don’t get 14 to 16 hours of strong light a day, most become spindly and weak. Although many gardeners start their seeds on windowsills, the light from a window during the short days of winter often isn’t enough to grow strong, sturdy seedlings.
A grow-light system will provide seedlings started indoors with enough light to produce healthy, compact transplants for the garden. Keep in mind that growing seedlings need lots of bright light. Keep the lights on for at least 14 hours a day, and suspend the lights close to seedling leaves. Because tubes produce less light at the ends, choose the longest tubes you have room for and rotate seedlings at the ends into the middle every few days. Keep the tubes clean. Dust can decrease the amount of light available. To increase light from a fluorescent fixture, position a mirror or aluminum foil alongside it to reflect light back onto seedlings.
Most seedlings will do well if you grow them beneath fluorescent lights. You can buy expensive grow lights, but the 4-foot-long shop lights sold at hardware stores work just as well and cost much less…
4. Organic Seedling Fertilizer (Optional depending on your potting soil)
Seedlings growing in a soil-free or lean potting mix will need small doses of plant food, starting at the time the first true leaves develop. For the first 3 weeks, water them once a week with a half-strength solution of fish or seaweed fertilizer, compost tea, or one of the liquid organic fertilizers specially formulated for seedlings. After that, feed the seedlings with a normal-strength solution every 10 to 14 days. If you’re growing your seedlings in a potting mix that contains compost or other nutrients, you may not need to feed them as often.