Starting seeds indoors in plastic flats or small pots filled with sterile soil is one way to get your garden off to an early start. Once the seedlings have reached a suitable size and the weather is right, you transplant them outdoors to where they will grow to maturity. Another option is to plant seeds directly into soil outdoors. Planting seeds this way is called direct sowing or direct seeding, and it can yield great results.
Unlike starting your seeds indoors, direct sowing involves dealing with unpredictable elements, such as weather, wildlife, and insects. Despite that, many vegetables, flowers, herbs, and even some native trees and shrubs, sprout easily from seed sown directly into garden soil.
Some vegetables, such as carrots or radishes, have long tap roots that can be damaged when transplanted as seedlings. These are best planted by direct sowing. Beets can be successfully transplanted, but they prefer growing in cool soil so there’s no reason to start them indoors.
Heat-loving crops that need a long growing season to mature or are slow to germinate, such as tomato, pepper, or eggplant, often don’t produce as well as when they’re direct-sown, especially in regions with short growing seasons. Start these seeds indoors where you can provide more exacting conditions or purchase transplants. Other heat-loving crops with large seeds that germinate quickly, such as pumpkin, squash, cucumber, beans, and melons, thrive when direct-sown after all danger of frost is past.
Some flowers, including Sweet Pea, Larkspur, and Bachelor’s Buttons, and many wildflowers, germinate best in cool soil. They should be direct-sown early in the growing season. Or, in mild winter climates, such as the South and the Southwestern United States, you can plant in fall. The seed will germinate in autumn and then mature the following spring. Even in colder climates, some hardy flowers, including many wildflowers, can be sown in fall. The seeds will germinate when conditions are right the following spring. You should also direct-sow flowers that don’t transplant well as seedlings, such as Morning Glory, Nasturtium, Poppies, and Moonflower.
Annuals that need a long time to grow from seed, or have exacting germination requirements, are best started indoors or from transplants. These would include Cleome, Petunia, Impatiens Nicotiana, and Amaranth. Other heat-lovers, such as Coreopsis Cosmos, Marigold, Sunflower, and Zinnia, grow quickly from direct-sown seed.
Direct Sowing, Step-by-Step
Prepare the seedbed. This will be easiest to do if the ground has been watered and then allowed to dry for a few days. Level the ground with a steel rake, break apart large soil clumps and remove debris, such as sticks, weeds, rocks and roots. Spread a 2-3-inch layer of organic matter, such as compost, over the area and apply fertilizer according to label instructions. Turn the soil with a spade or hand fork, thoroughly working in the organic matter. Finish by raking to create a level planting surface.
Plant at the right depth | Planting depth is very important. Plant too deep and the seedlings won’t be able to reach the surface; not deep enough and the seeds will dry out before germinating. Check the seed packet for proper planting depth. The general rule of thumb is to plant at a depth equal to three times the seed diameter. However, there are many exceptions. Some seeds require light to germinate and should not be covered with soil. Press such seeds firmly against soil using a board or trowel to ensure they remain in good contact with moist soil.
Important Readings for seed-sowing outdoor
- If your soil has a high clay content and tends to crust over as it dries, cover seeds with potting soil or weed-free compost.
- When sowing extremely small seeds, such as carrots or nicotiana, mix seeds with sand so they are easier to spread evenly.
- When sowing larger seeds, including peas and beans, create a long furrow and sprinkle seeds at the proper spacing. Or you can use a stake, dibber or pencil to form individual planting holes. Once the seeds are in place, cover with the appropriate amount of soil.
Keep seeds moist | After planting, wet the seedbed with a gentle mist or shower. A strong splash or spray will likely dislodge the seeds. It’s very important to keep the soil consistently moist and not let the seeds dry out. In a sunny spot, this may mean watering at least twice a day.
Mark the planting area | This is especially important if the seeds have been sown between existing plantings. You want to know exactly where they are so you can water properly and check germination progress. Use garden markers, stakes, and string, tall sticks, plastic cutlery — whatever will clearly define where the seeds were sown.
Know your seedlings | The seeds should all germinate about the same time, so it should be easy to distinguish what you planted from weeds simply from your planting pattern. If not, try to learn what your seedlings should look like so you don’t mistakenly pull them. Check seed packets or look for illustrations or photos online. When in doubt, let all the seedlings be until you know for sure what’s friend or foe.
Thin the ranks | No matter how careful you are, some seedlings will come up too close together. If you don’t thin your seedlings as directed on the seed packet, they won’t mature properly. You’ll disturb roots less if, instead of pulling seedlings by hand, you snip them at the soil line with a fingernail or a tiny pair of snips or scissors.
Watch for pests | Tender seedlings are easy prey for insects. Protect against Slugs, Snails, Cutworms, and other insect pests with appropriate Natria Products. Always read and follow label instructions.