Determining what seeds you can plant now relies entirely on your specific geographic location and the current stage of your local growing season. Successful gardening begins with a careful assessment of the climate conditions that dictate when tender young plants can safely thrive outdoors. This evaluation is necessary whether you plan to start seeds in a protected indoor environment or sow them directly into the garden soil. The timing of these initial planting decisions ultimately governs the health, maturity, and productivity of your entire garden throughout the season.
Defining Your Planting Window
The single most important factor for any gardener is the Last Average Frost Date (LAFD) for their region, which represents the approximate day in spring when the risk of a freeze drops to an acceptable level. This date is calculated using historical weather data, serving as a threshold for planting frost-sensitive crops. You can find this information by consulting your local cooperative extension office or by using online tools that reference NOAA climate data for your zip code.
While the LAFD dictates the start of the planting season, the USDA Plant Hardiness Zone Map provides a broader context by indicating the average annual minimum winter temperature in your area. This zone designation helps determine which perennial plants can survive the winter, but it is less precise for timing spring planting than the LAFD. Understanding both the LAFD and your hardiness zone allows for a localized and informed approach to the seasonal planting schedule.
Seeds Requiring Indoor Starting
Certain plants need an early advantage because their full life cycle demands a longer growing season than most climates provide. These crops must be started indoors, often six to ten weeks before your LAFD, to ensure they reach maturity before the first frost in autumn. This protected environment provides the consistent warmth and controlled conditions required for delicate or slow-germinating seeds.
Warm-weather vegetables like tomatoes, peppers, and eggplant require high, sustained soil temperatures, often 75°F or warmer, to germinate reliably and grow vigorously. Starting them indoors allows seedlings to develop a strong root system and several sets of true leaves before being subjected to the outdoor elements. Slow-growing plants, such as celery and cauliflower, also benefit from an indoor head start to maximize their time in the garden.
Most bell and chili peppers require a longer lead time, typically eight to ten weeks before the LAFD, due to their slower initial growth rate. Tomatoes are often started six to eight weeks before that date. Calculating this back-timing from your specific LAFD is the most precise method for determining your indoor sowing schedule.
Seeds Suitable for Direct Outdoor Sowing
The majority of seeds fall into two categories for direct outdoor sowing, depending on their tolerance for cool soil and frost exposure.
Cool-Season Crops
Cool-season crops are hardy and can be planted as soon as the soil is workable in early spring, often several weeks before the LAFD. These crops thrive in temperatures between 40°F and 65°F and will quickly bolt once the weather becomes too hot.
Very hardy vegetables can be sown directly into the soil approximately two to four weeks before the estimated LAFD. These include:
- Peas
- Spinach
- Radishes
- Lettuce
Root vegetables like carrots and beets also prefer direct sowing, as their taproots do not transplant well, and they should be planted when the soil temperature reaches about 40°F.
Warm-Season Crops
Once the danger of frost has completely passed and the soil has warmed, generally above 60°F, you can plant warm-season crops directly into the garden. This group includes vining plants and heavy feeders:
- Squash
- Melons
- Cucumbers
- Beans
- Corn
Corn requires warm soil, and planting too early will result in poor germination and stunted growth. Bush and pole beans germinate best when the soil temperature is consistently above 65°F.
Immediate Care Following Planting
Whether you have transplanted seedlings or sown seeds directly, the period immediately following planting requires focused attention to ensure survival. Seedlings that were started indoors must undergo a process called hardening off before being permanently moved to the garden. This transition involves gradually exposing the plants to outdoor conditions like direct sunlight, wind, and cooler temperatures over a seven to fourteen-day period.
Start by placing the seedlings outside in a shaded, protected spot for just one hour on the first day, increasing the exposure time daily while avoiding harsh winds or temperatures below 45°F. This slow acclimatization encourages the development of a thicker cuticle layer on the leaves, reducing the shock that often leads to stunting or death.
Simultaneously, for all newly planted seeds, consistent moisture is necessary, as the delicate germinating seeds and young roots will dry out quickly. Seedlings from direct sowing will eventually require thinning once they reach two to three inches in height. Thinning involves removing the weaker plants to ensure the remaining seedlings have adequate space and resources to mature fully, preventing overcrowding and competition for light, water, and nutrients. This focused care in the initial days establishes a strong foundation for the entire growing season.