Seedling Transplant Calculator

Perfect Timing for Seedling Success

Starting seeds indoors extends your growing season and saves money compared to buying nursery starts. However, timing is everything—start too early and seedlings become leggy and root-bound; start too late and you miss peak growing season. Our seedling transplant calculator uses your last frost date and specific plant requirements to determine optimal seed starting and transplanting dates.

Different vegetables have different timelines. Tomatoes and peppers need 6-8 weeks indoors before transplanting, while cucumbers and squash only need 3-4 weeks (they grow fast and dislike root disturbance). Cool-season crops like broccoli and cabbage can be transplanted 2-4 weeks before last frost, while heat-lovers like basil and eggplant must wait until soil warms to 60°F+.

Hardening Off for Transplant Success

Hardening off is critical but often overlooked. Seedlings grown indoors are tender—direct transplanting into garden sun and wind shocks them severely. Our calculator provides a hardening-off schedule: gradually expose seedlings to outdoor conditions over 7-10 days, starting with 1-2 hours of morning sun and increasing daily. This process toughens cell walls and prevents transplant shock.

Succession planting maximizes harvests by planting the same crop at 2-3 week intervals. Our calculator helps plan multiple plantings for continuous harvest rather than one overwhelming glut. For example, plant lettuce every 2 weeks from early spring through early summer, then resume in late summer for fall harvest. This strategy ensures fresh produce throughout the season rather than feast-or-famine cycles.