Watch the Weather for the Best Time to Sow Seeds
The key to direct sowing is to pick the right weather. Working back from your average last frost date, using the seasonal benchmarks below, will tell you approximately when you'll need to sow each type of seed. Watch the weather reports and plant promptly when proper conditions exist. Or put the information in the app which determines these dates based on your closest weather station, which provides more specific information than hardiness zones.
Seasonal Benchmarks
Early Spring: Soil temperature is cool, but past the last hard freeze or heavy frost. May still have light frost.
Late Spring: Soil has begun to warm, and danger of frost is past.
Early Summer: Soil temperature and night temperatures have warmed.
Late Summer: Soil and night temperatures have begun to cool, but still before first frost.
Fall: Soil temperature has cooled and light frosts occur, but before first hard freeze or heavy frost. Ground is not frozen.
Winter: Soil temperature is very cold or soil is actually frozen. Hard freezes and heavy frosts; soil may freeze.
It may be helpful to use a planning chart like the example given below: (Example for Lexington, Va.)
SeedType | TransplantSeason | Transplant Date in My Area | No. Weeks from Sowing to Garden-size Transplants | Date to Sow |
| Ageratum | Early Summer | May 1 - 15 | 6 to 8 | March 15 |
Or have the information calculated for you in the From Seed to Spoon app!
Seed Bed Preparation
Prepare the seed bed by turning the soil over to a depth of 6-8 inches with a spade or spading fork. (Be sure to call 811 to avoid damaging underground facilities.) Break up clumps with a rake (a rototiller does this job well mechanically). Rake the surface as level as you can with a steel-tined garden rake. Shape and smooth your beds so there are no large clods or dips on the planting surface, which should be level. Firm down the surface before planting. AVOID WALKING ON RAISED BEDS, as this results in over-compaction of the soil and hampers root development. Don't plow when soil is too wet. If soil does not crumble after squeezing, it is too wet.
Sowing Seeds Outdoors
See your packet for detailed sowing instructions, which vary with each type of seed. Make a furrow to the depth indicated on your seed packet. After sowing, fill in the furrow and firm down. EXCEPTION: Some smaller seeds such as lettuce prefer light to germinate and should barely be covered. This is noted on your seed packet.
Care After Sowing
Until seeds have sprouted, keep the seed bed moist, never allowing it to dry out. Water with a fine-spray hose nozzle or watering can which will provide a fine misty spray and not wash away the soil. Water often enough (usually about once a day) so that the soil surface never dries out, but remains constantly moist. Covering the bed with Park's Plant Protector helps in warming the soil and conserving moisture.
In spring, when weather is favorable, keeping soil moist is easily done; but in summer, the beds need to be shaded or mulched to slow evaporation.
As the seeds germinate, the seedlings may grow too close together. It is important that you thin them, according to the instructions on the seed packet. Do not be softhearted when it comes to thinning . . . too many plants too close together produce the same effect as a serious weed infestation.
Crops vary considerably in their requirements for nutrients and care; see Park's Vegetable Growing tips for some information concerning fertilization. Mulching will save time and effort, conserve moisture, keep soil cooler, and keep down weeds.
Sowing Perennials and Annuals Outdoors
Many types of flowers are sown outdoors in fall or spring, when changing weather encourages germination.
In the North, sow from early spring through summer. Allow at least 4 months from sowing till first killing frost, so plants will have time to grow big enough to endure winter weather.
In the South, sow seeds that require cool germination temperatures in spring or fall.
Seeds sown in hot weather may need shading. If a cold frame is used, cover the sash with burlap. Build a frame over your seed bed to support shading material like boards, burlap, or heavy cloth. Remove the shading material gradually as the seeds come up.
Perennials and Annuals for Fall Sowing
Your packets will recommend certain types of seed for late fall sowing. The purpose of this is not to have the seed germinate in autumn, but rather to give the seed a cold period to make it ready to grow with the first favorable weather of spring. Plant slightly deeper than you would in spring. Protect the sides of the bed with boards to prevent seeds washing away. Apply a protective mulch as soon as the ground freezes. Ideal sowing time is just before this happens.
From Philadelphia southward, flowers such as Larkspur may be sown in September so that the seeds will germinate in the fall. With a protective mulch applied after the ground freezes, they will live over winter and produce extra early, long-stemmed flower spikes. From Washington, D.C. southward, Sweetpeas can be handled this way. From southern Virginia southward add Dianthus, Phlox, Poppy, Calendula, Alyssum, Nemophila, Candytuft, Eschscholtzia, Bachelor's Buttons, Clarkia, Nierembergia, Gypsophila, and Nigella to the list.
Garden Care After Sowing
After your seedlings are up and established and your transplants have had a week or two to root in, you'll receive your greatest reward from gardening the time of bloom and harvest that you've been looking forward to. Here's what you should do to make your garden flourish during this time.
How Much Water Do Your Direct Sow Seeds Need?
The best source of water for your garden is rain; as long as rain keeps your soil moist beneath its mulch, no irrigation is needed. An actively growing garden requires at least 1 inch of rain per week; if such is lacking, or you see your plants wilt during the warmer part of the day, you probably need to irrigate. During the first 3 weeks after setting out, check soil moisture weekly. If the surface is dry beneath the mulch, dig down 6 inches with a trowel. If the soil is still dry at that depth, water your bed. Later in the season, after roots have reached deep into the soil, you need to water only if signs of wilting appear.
Water deeply but not too frequently. Soak the garden for up to 4 hours at a time, letting water soak deep, then let upper soil layers dry out before watering again. This promotes deep root growth, more lasting beauty and better harvest from your plants, and helps retard weed growth.
Several irrigation methods are effective. Ground watering, with trickle tubes or a carefully placed hose, soaks deep and avoids wetting foliage or flowers (which often encourages disease), but these devices are sometimes hard to set up or move. Impulse jet sprinklers lay down a lot of water fast and are easy to move around, but can beat small or tender plants down. A fine spray sprinkler of the oscillating or whirling type is both gentle and easy to move, but slower.
Feeding Your Plants
Generally, yellowish (not brown or wilted) leaves and slow growth mean more nutrients are needed. Your local county extension office can provide experitse on growing in your area. When fertilizing, use the side-dressing approach by leaving the granules 3-4 inches away from the plant.
