Seasons and Greenhouses
Frost Free Growing Season Calculator
Planning frost-free season starts with consistent values for first fall frost day and last spring frost day. This calculator performs that arithmetic.
Enter values for frost-free season
Frost Free Growing Season needs first fall frost day and last spring frost day from one case.
Scope of this frost-free season calculation
The planning question for Frost Free Growing Season is whether you can calculate days between average spring and fall frost dates. Frost Free Growing Season measures this portion as Frost-free season. A separate estimate of accumulated GDD comes from Growing Degree Day Accumulation Calculator.
Record adjustments outside Frost-free season separately. Transmitted light? See Shade Cloth Light Reduction Calculator.
Frost Free Growing Season beyond the formula
Average frost dates are probabilities, not guarantees.
Formula for frost-free season
Frost Free Growing Season finds the difference using First fall frost day and Last spring frost day. Heat loss: Greenhouse Heat Loss Calculator handles this follow-up.
For the prefilled measurements—first fall frost day at 285 day and last spring frost day at 110 day—the calculated answer is 175 days.
Reading frost-free season
Frost-free season carries the planning decision here. Keep the measurement basis consistent across alternatives.
Before entering first fall frost day
Prepare First fall frost day and Last spring frost day for Frost Free Growing Season. Keep unrelated records separate.
- First fall frost day
- Default in Frost Free Growing Season: 285 day.
- Last spring frost day
- Default in Frost Free Growing Season: 110 day.
Field notes for Frost Free Growing Season
Place sensors near the crop zone and away from direct heater discharge or unrepresentative sun. Several points may be needed in a large structure.
Documenting frost-free season
Retain a dated Frost Free Growing Season worksheet containing First fall frost day and Last spring frost day.
Save Frost-free season before adding a reserve, purchase rounding, or another practical adjustment.
Document the final field outcome and compare it with frost-free season without changing the first record.
A second Frost Free Growing Season scenario
Test Frost Free Growing Season with First fall frost day at 313.5 day rather than 285 day. The displayed frost-free season becomes 204 days instead of 175 days.
The test holds last spring frost day constant.
Test a measured range for first fall frost day when it may alter the decision.
Questions about Frost Free Growing Season
How does “Average frost dates are probabilities, not guarantees.” affect frost-free season?
Account for it in the source measurement for first fall frost day; the formula has no additional correction for it.