By The National Gardening Association, Bob Beckstrom, Karan Davis Cutler, Kathleen Fisher, Phillip Giroux, Judy Glattstein, Michael MacCaskey, Bill Marken, Charlie Nardozzi, Sally Roth, Marcia Tatroe, Lance Walheim, Ann Whitman
You can plant vegetable seeds indoors or outdoors. If you plant seeds indoors, you transplant them into your garden later. With direct seeding, you skip the indoor step and sow the seeds directly in your garden. If you’re serious about growing vegetables, you’ll probably end up using both options. Consider these points when making your choice:
- You get a jump on the growing season when you sow seeds indoors. This process is called seed starting (or starting, for short). If you start at the right time, you can have vigorous seedlings ready to go into the ground at the ideal time. In areas with short growing seasons, starting seedlings indoors really gives you a head start.
- The best candidates for an early start are plants that tolerate root disturbance and benefit from a jump on the season, including broccoli, Brussels sprouts, cabbage, cauliflower, celery, eggplant, leeks, onions, parsley, peppers, and tomatoes.
- Seeds are easier to start indoors than outdoors. You can more easily provide the perfect conditions for hard-to-germinate or very small seeds, including the ideal temperature, moisture, and fertility.
- Some vegetables don’t like to be transplanted. These vegetables include many of the root crops, such as carrots, beets, turnips, and parsnips. They’re cold-hardy vegetables, so you can direct seed them pretty early anyway. Crops like corn, beans, and peas are also pretty finicky about transplanting and grow better when you direct-seed.
Transplanting seedlings into the ground
Harden off vegetable seedlings that have been grown indoors or purchased from a greenhouse before exposing them to the elements. Hardening off is a way of increasing your plant’s stamina before planting — similar to slowly acquiring a base tan before taking that outdoor, tropical vacation. Plants that have been growing outside at the nursery can go right into the ground, but greenhouse-grown plants are lush and soft and have never known a single day of sunshine in their lifetimes. You have to introduce them slowly to the harsh, real world.
To harden-off seedlings, leave the plants in their containers and put them in a shaded area with some indirect light for a few days. A north-facing, covered porch is ideal. Whenever a freeze is predicted, bring the plants inside overnight. If these are shade plants, you can leave them in this protected site for a few more days and then put them in the garden. For sunny-spot plants, give them a few days in the shaded area and then place the plants in a sunny location for an hour one day. Give them a couple of hours of sun the next day, and so on, increasing their exposure each day. At the end of a week, the plants are thoroughly accustomed to sunlight and wind and are ready to go into their new home.
Don’t overharden your plants. Certain crops, such as cabbage and broccoli, can bolt (flower before they’re supposed to) quickly if seedlings over three weeks old are repeatedly exposed to temperatures lower than 40°F (4°C) for a couple of weeks.
Before transplanting your seedlings, you need to prepare your soil and sculpt beds or rows, and your garden must be ready to plant. When setting out plants in biodegradable peat pots, make slits down the sides of the pots or gently tear the sides to enable the roots to push through. Also, tear off the lip (top) of the pot, so that it doesn’t stick up above the soil surface and pull moisture out of the soil. With premade growing blocks encased in netting, cut off the netting before planting.
Choose a calm, cloudy day to transplant, if possible. Late afternoon is a good time because plants can recover from the shock of transplanting without sitting in the midday heat and sun. If you don’t get an ideal transplanting day and the weather is hot and sunny, shade the plants until the sun goes down. Don’t be alarmed if your plants look a little droopy after you set them out because they’ll soon recover. Cabbage seedlings can droop and look almost dead, for example, and then be up and growing in a day or two.
Sowing seeds directly in your garden
Unless you live in an area where summers are really short, you’re better off sowing some types of vegetables directly in a garden. Large-seeded, fast-growing vegetables, such as corn, melons, squash, beans, and peas, usually languish if they’re grown in containers for even a day or two too long.
Before direct seeding, make sure that the soil has dried out sufficiently before you work it, and be sure that the soil is warm enough for the seeds that you want to plant. Pea seeds, for example, germinate in soil as cool as 40°F (4°C), and you can plant them as soon as you can work the soil in spring. Squash seeds, on the other hand, need warmth. If your soil temperature is much below 65°F (18°C), the seeds are likely to rot in the ground before they sprout. The best way to determine the temperature of your soil is to use a soil thermometer, which you can buy at a garden store.
You can plant seeds in a variety of patterns. The method that you choose depends on your climate, your tools, and your taste:
- Row planting: Mark the placement of a row within your garden, and then make a furrow at the correct depth along the row. Some seeds may not sprout, so sow seeds more thickly than you want the final spacing of the crops to be. Thinning rows is less of a chore if you space seeds as evenly as possible. Cover the seeds with fine soil and then firm them in with the back of a hoe to make sure that all the seeds are in contact with the soil. Water gently. If you plan to use furrow irrigation, fill the furrows with water first and then push the large seeds into the top of raised beds.
- Wide row planting: This method allows you to plant more seeds in less space by concentrating watering, weeding, and fertilizing in a smaller area. Rows are generally 10 to 16 inches (25 to 41 cm) wide. Sprinkle seeds over the entire row — with most crops, try to land the seeds about 1/2 to 1 inch (1 to 2 cm) apart. For peas and beans, space them 1-1/2 to 2 inches (4 to 5 cm). Cover small seeds with a thin layer of potting soil. Lightly pat the potting soil down again to bring the added soil into firm contact with the seeds.
- Bed planting: Planting in beds is essentially the same as planting wide rows.
- Hill planting: Plant seeds for vining crops that spread out, such as squash, melons, or cucumbers, in hills or circular groups. Loosen the soil in a 1-foot-diameter (30 cm) area, level the area, and then plant five to six seeds close together. Thin out all but the two strongest seedlings.
- If your soil is heavy, you may want to plant in a raised hill, or mound. The raised soil warms up more quickly than the surrounding soil and drains better. Just don’t let the mound dry out!
Soon after seedlings grow their second set of true leaves, you need to thin them out to avoid overcrowding. (The first set of leaves that a seedling produces are called seed leaves or cotyledon, which are followed by the true leaves.) When you thin plants, either discard the extra seedlings or move them to another part of your garden.
Newly transplanted seedlings need extra attention until they get established. Shade them from the hot sun for a day or two and be sure to keep them well watered.