How to Start Plant and Vegetable Seeds

One of the most hopeful—and wondrous—things any of us can do is to grow our own garden from seed. Whether we’re nurturing ‘Mortgage Lifter’ tomatoes, French marigolds, or garlic chives “from scratch,” the process brings us closer to nature—and teaches us a thing or two about patience, commitment, and luck.

Coddling tender seedlings is the trickiest part of seed starting but well worth the effort, considering the benefits of home-sown plants. The cost savings alone is a major perk. At big-box stores, tomato starts command up to $3 per plant—the same price as a packet of quality seed. Plus, “there are hundreds of hybrids and heirlooms available as seeds that you’ll never find at garden centers,” says Niki Jabbour, an author and radio host based in Nova Scotia, Canada, who grows enough produce in her backyard to keep her family stocked year-round. As a gardener who’s learned many lessons the hard way, Jabbour advises to “always plant fresh seed at the right time.” Germination rates decline as seeds age, and starting seeds indoors too early yields weak, wiry plants.

To figure out when to sow, use your region’s average last frost date as your planting (or transplanting) target and, if you’re starting seeds indoors, consult the seed packet for the number of weeks it will take the seedlings to mature. Germination time varies by crop, so don’t plan on sowing your entire vegetable garden on the same day. Then give the seedlings a solid start with the following step-by-step guide.

Shown: With each packet yielding dozens of plants, seeds are the most economical way to fill a garden fast.

Step 1

Decide Whether to Start Inside or Outside

Although heat-loving tomatoes, peppers, and eggplants need a head start indoors, you can sow most flowers and edibles directly into the garden once nighttime temperatures hover above 50 degrees F. Check the seed packet for details on spacing and planting depth, and sow sparsely in rows to make thinning less of a chore. A seed dispenser (shown) or folded postcard can make tiny seeds easier to handle.

Tip: To encourage seeds to sprout a little sooner, soak them in warm water for a few hours right before sowing.

Step 2

Prep Indoor Pots

If you’re starting seeds indoors, avoid exposing seedlings to pathogens by cleaning used containers with hot, soapy water and opting for a sterile soilless mix. Seeds will germinate in any container with drainage, from peat pots to plastic cell packs or even yogurt cups with holes punched in the bottoms. You might also try soil blocks, a potless option that involves cutting out brownie-like cubes of damp starter mix.

Shown: Hand-held Soil Blocker, about $30; johnnyseeds.com

Step 3

Sow With Care

Moisten your starter mix or garden bed before you sow. Take the time to place each seed individually, sowing as deep and far apart as the seed packet recommends. In a starter cup, one or two seeds is plenty. Otherwise, they’ll compete and struggle to germinate. For teeny-tiny seeds, like lettuce and carrots, simply sprinkle them over damp soil or mix, then mist with a spray bottle.

Step 4

Mimic a Greenhouse

Once your seeds are sown, keep them warm and moist. Indoors, water from below whenever the soil feels dry, and keep them covered with plastic wrap to boost humidity. For seeds planted outdoors, place a lightweight row cover over the sown plot to create a similar greenhouse effect. In both cases, the second you notice sprouts, remove all covers. Stale air and soggy soil invite fungal diseases.

Step 5

Ensure Adequate Light

For optimal growth, seedlings need 15 hours of bright light each day—a tall order in late winter. “Indoors, a sunny window works in a pinch, but consider investing in a grow light if you start seeds every year,” Jabbour says. Place the light 2 inches above the seedlings, raising it as they grow. Plenty of bright light, regular watering, and weekly feedings of diluted fish emulsion are the keys to growing healthy transplants.

Step 6

Limit The Competition

Once seedlings grow a second pair of leaves, it’s time to thin out the weaklings to achieve the desired spacing. Snip, rather than pull, the scrawniest sprouts to avoid causing root damage to the ones you want to keep. Indoors, leave just one plant per starter cup.

Step 7

Prepare to Plant

Indoor seedlings get pretty pampered on a windowsill, so you need to introduce them to the outdoors slowly. Once plants have three to four sets of leaves and a full tuft of roots, set them out in shade on a mild spring day. Gradually expose the seedlings to more and more sunlight, bringing them inside at night. Within a week, they’ll be ready to stay outside full time. If you can, wait for an overcast, even drizzly, day to plant in the ground. Gently ease the seedlings from their pots, starter mix and all, and settle them into moist holes. Peat pots and soil blocks can go directly into the ground.

Step 8

Protect Tender Plants With a Row Cover

Once the seedlings are planted, a lightweight row cover is your best defense against the elements. Use one to further harden off new transplants, shield them from late frosts, and guard against insects, such as cabbage worm and cucumber beetle. Just this little added protection could make the difference between a disappointing crop and a bountiful summer harvest.

Tip: Keep an oscillating fan running as the seedlings grow. The moving air helps prevent fungal disease and readies the stems for windy outdoor weather.