When to Plant Tomatoes Outdoors
Plant tomatoes outdoors only after the danger of frost has passed and nighttime temperatures are reliably above about 50°F. For fastest establishment, wait until soil has warmed and daytime weather is settled, rather than planting on the calendar date alone.
Find your area's average last spring frost date through a local Cooperative Extension office, weather service, or garden calendar. Treat it as a planning guide, not a guarantee. Delay planting if a late frost, cold rain, or extended cool spell is forecast.
Tomatoes are warm-season plants and grow slowly in cold soil. A soil thermometer is useful: soil around 60°F or warmer is a better target for transplanting than merely frost-free air. Raised beds and black plastic or other approved soil-warming mulch can help soil warm earlier in cool regions.
Harden off indoor-grown transplants for about seven to ten days before planting. Start them in a sheltered outdoor location for a short period, then gradually increase exposure to sun, wind, and outdoor temperatures. Bring them under protection if frost or harsh weather is expected.
Choose stocky plants with sturdy stems and healthy green leaves. Avoid setting out plants that are severely root-bound, wilted, or carrying obvious disease symptoms. If transplants already have blossoms, planting them carefully and keeping them evenly watered helps reduce stress.
Plant in full sun, generally at least six to eight hours daily, in well-drained soil amended according to a soil test. Set tomatoes deeply, burying part of the stem after removing leaves that would be below the soil surface. Many tomato varieties form roots along a buried stem, which helps anchor the plant.
Provide support at planting time for varieties that need it, then water the root zone thoroughly. Use mulch after the soil has warmed to moderate moisture loss and soil splashing. Keep row covers or other frost protection available early in the season, and follow local Cooperative Extension guidance for your climate.
Frequently asked questions
What temperature is too cold to plant tomatoes?
Frost can kill tomato plants, and repeated nights near or below 50°F can slow and stress them. Wait for frost-free weather and reliably mild nights.
Can I plant tomatoes before the last frost date with protection?
Only if you can reliably protect plants from frost and cold conditions. For most home gardens, waiting until after the frost risk is simpler and more dependable.
Should tomato seedlings have flowers before planting outside?
They may, but flowers are not required. Healthy, hardened-off plants establish well whether or not they have begun flowering.
General guidance for US home gardens. Conditions vary by region and season; check with your local Cooperative Extension office for site-specific advice. Page updated Aug 4, 2026.