Direct-Seeding Guidelines from Johnny's • How to Direct-Sow Your Seeds in the Garden or Field

Before seeding ensure that soil temperature and moisture are adequate, to promote consistent and even germination. Identify your plant hardiness zone beforehand or contact your local Cooperative Extension Service to determine appropriate planting date, to avoid late-spring and early-fall frosts that can damage or destroy your crop. Seeds planted in soil that is too wet or cool may rot or germinate poorly.

Soil Temperature & Johnny's Germination Guides

Air temperature (ambient temperature) and soil temperature usually differ. For direct sowing, focus on the correct soil temperature.

Germination Guide for Carrots

See each variety's product description webpage or the catalog for its optimum germination range.

For most crops, a soil temperature of 55–65°F (13–18°C) is an acceptable range for germination, though some prefer or require cooler or warmer soil temperatures.

For best results, refer to the Germination Guides shown on each product page and in our catalogs for optimum temperature range. In the example shown here for carrot, germination can take place within the wide range of 41°F to over 95°F, but peaks between 68°F to 86°F, with an optimal temperature of 77°F.

Check the soil temperature with a soil probe thermometer prior to sowing to avoid poor germination.

Special Seed Treatments Prior to Planting

Certain crops, especially many flowers, need an extra step prior to sowing, to help the seed overcome dormancy barriers. Treatments can include soaking the seed, stratifying the seed, or scarifying the seed.

For instance, sweet peas benefit from soaking for 24 hours prior to sowing. Should soaking the seeds prove insufficient to break dormancy, the seeds can be nicked with a small file or rubbed with sandpaper.

In many though not all cases, pelleted seeds are primed during the pelleting process, to increase germination uniformity and break thermal or light dormancy. (To learn more, read About Our Seeds.)

Sowing Seeds

Sow each crop at its appropriate sowing rate, depth, and spacing between rows. When direct seeding, the sowing rate is typically higher than when seed-starting indoors for transplants. Direct seeding exposes the seeds to the elements, and seeding at the recommended rate can ensure there are enough seedlings for a good stand.

As a rule of thumb on seeding depth, most small-seeded crops can be sown ⅛–¼" deep and larger seeded crops ½–1" deep.

Watering

Once sown, water in the seeds so that there is adequate and even moisture and seed-to-soil contact. Mist or lightly water small seeds to avoid displacing them. Ensure even and consistently moist, but not overly wet conditions until germination. The germinating embryos and small seedlings are delicate and need consistent moisture to fully germinate and complete the earliest life stages; a dry period can kill them. Note that pelleted seeds require more water initially to split or dissolve the pellet and allow for germination.

Watering

Water as necessary to prevent the soil from drying out. This could be as often as once per day or not at all, depending on rainfall, temperature, and sunlight levels.

Weeding

Weed regularly. Weeds compete with crops for nutrients, water, and space. It is critical to keep the crop weeded until the seedlings are large enough to outcompete weeds.

Mulching

Mulching can reduce weed pressure and conserve moisture. Once the seedlings are well-established, a layer of mulch can be added. Mulching materials can include straw, grass clippings, leaves, or many other readily-available materials. Avoid materials that harbor weed seed. Alternatively, lay paper or plastic mulch prior to sowing. (Note that only jab-type seeders can be used to direct-sow through plastic.)

Thinning

Thinning is the process of removing excess seedlings in high-density stands once they have developed their first set of true leaves. This allows the other seedlings room to grow and access to nutrients. Thin the crop to the correct stand by cutting or pinching out the stem to prevent disturbing the root system of the remaining seedlings. Thinnings can be left in the soil or composted.

Fertilizing

If needed apply a soluble fertilizer about 4 weeks post-germination. Follow the instructions on the label. Fertilize about once per week. If the crop looks green and healthy there is usually little or no need to fertilize.

• Poor germination and thin stands. These can be caused by a number of factors, including the following.
• The soil could have been too cold or damp at time of sowing.
• If a seeder was used for sowing, it may not have been correctly calibrated to the size of the seed, resulting in skipping and/or the seeds being planted too shallow or too deep.
• Insects, birds, or other pests or pathogens could have damaged the planting.
• Too much water could have caused the seed to rot.
• Birds and other animal pests. One of the earliest challenges when direct-seeding crops is to prevent the seeds from being eaten by birds, mice, and other small rodents.
• Shield newly-sown seeds with bird netting or row cover if birds are an issue.
• Repel rodents by applying Plantskydd^®.
• Slow maturity. Seedlings started indoors for later transplanting receive ideal conditions during the germination and early-growth stages, leading to faster initial growth. In contrast, the date for direct-seeded crops is limited by acceptable planting temperatures at the beginning of the growing season. Ensure an early planting for long-season crops, or grow transplants.
• Weed competition. Newly-germinated and young seedlings may have trouble competing with weeds, as they won't have extensive root systems to reach nutrients or a large canopy to shade out weeds. Remain attentive to weed pressure to prevent weeds from overtaking the crop.
• Elevated insect pressure. Small direct-sown seedlings are at greater risk of succumbing to insect pressure than transplanted seedlings. Their leaves are more tender and feeding by insects can do a lot more damage to a small plant. Row covers may offer some protection plus additional warmth for direct-sown crops.

• Key Growing Information for Vegetables, Fruits, Herbs, Flowers & Farm Seed  • Index
• Direct-Seeded Vegetable Crops • Seed Quantities Needed for Sowing & Average Yield per 100' Row/Acre • Chart
• Eliot Coleman's 6-Step Bed Preparation Method • Article
• Guide to Choosing a Small-Scale Seeder • Article
• Guide to Small-Scale Bed Preparation Tools  • Article
• Guide to Small-Scale Weeding & Cultivation Tools • Article
• Plant Hardiness Zone Map
• Cooperative Extension Service
• Downloadable, printable version of this article  • PDF