Harvest Date & Sowing Planner

Planning Harvest Windows

Days to maturity (DTM) describes how long a crop typically takes to reach harvestable size after sowing. However, actual harvest timing depends on weather, soil temperature, and cultivar. Instead of a single date, many crops have a harvest window where quality is optimal. This planner creates a harvest start date at DTM and extends it by a configurable window length, so you can manage harvest labor and succession planting.

Frost risk is a critical factor for cool-season and warm-season crops alike. If the projected harvest window extends beyond your first frost date, cold-sensitive crops may suffer damage or fail to ripen. The planner highlights this risk so you can adjust sowing dates, select faster-maturing varieties, or use season extension techniques like row covers or high tunnels.

Use this tool for homesteading, market gardens, or precision farming schedules. For succession planting, simply input a series of sowing dates and compare harvest windows to ensure steady production. By pairing harvest windows with irrigation planning and nutrient management, you can align inputs with peak crop demand and optimize yield and quality.

Remember that DTM values on seed packets often assume direct sowing and ideal temperatures. Transplants can shorten field time, while cool soil can slow emergence. Some growers use growing degree days (GDD) to refine timing, but DTM is still a practical planning benchmark. If your crop is sensitive to day length or heat stress, consider shifting sowing dates or selecting varieties bred for your season. This planner gives a clear baseline so you can make those adjustments with confidence.

For long-season crops, it can help to count backward from a target harvest date, especially if you are planning for markets or community-supported agriculture boxes. Enter a tentative sowing date, check the harvest window, then adjust earlier or later until it aligns with your sales calendar. If you use transplants, you can subtract nursery days from the DTM to reflect the time plants already spent growing. Combining this planner with local frost data and variety-specific notes creates a resilient, repeatable planting schedule year after year.

Formula

Harvest start = sowing date + DTM. Harvest end = harvest start + window. Days remaining is the difference between today and harvest start. Frost risk is flagged if harvest end is after the first frost date.

Example Calculation

If you sow on May 1 and DTM is 75 days, harvest start is July 15. With a 14-day window, harvest end is July 29. If first frost is October 10, the crop is safe; if frost is August 1, the tool flags a risk.

FAQs

What is days to maturity (DTM)?

DTM is the typical number of days from planting to harvestable size.

Why include a harvest window?

Many crops have a harvest window rather than a single day, often 7–14 days.

How does frost date affect planning?

If harvest ends after first frost, cold-sensitive crops are at risk.

Can I use this for succession planting?

Yes. Stagger sowing dates to plan continuous harvests.

Are results private?

Yes, everything runs locally in your browser.

How it works

This calculator performs simple date arithmetic to produce harvest windows and frost risk warnings. All computation runs client-side for privacy and speed.

Disclaimer

DTM values vary by cultivar and climate. Use local extension guidance and adjust for real field conditions.