Skip to main content
Calcimator

Frost Date Planner Calculator

Plan planting dates around your frost dates. Calculate when to start seeds indoors, transplant, and direct sow.

Inputs

days
weeks

Results

Start Seeds Indoors (day)

92

Transplant Day (day of year)

134

Direct Sow Day (day of year)134
Last Planting Day (day of year)210
Growing Season160 days
How to Use This Calculator
  1. Enter your last spring frost date as a day of the year (e.g., April 30 = day 120) — find yours on the USDA Plant Hardiness Zone map.
  2. Enter your first fall frost date (e.g., October 7 = day 280) to calculate your growing season length.
  3. Enter the days to maturity from your seed packet and the crop's cold hardiness (1=Tender, 2=Semi-hardy, 3=Hardy).
  4. Enter the number of weeks you plan to start seeds indoors (0 for direct-sow crops).
  5. Review the Indoor Start Day, Transplant Day, and Last Planting Day outputs to build your complete planting calendar.

How the result changes with Last Spring Frost (day of year)

Last Spring Frost (day of year)Start Seeds Indoors (day)Transplant Day (day of year)
21-735
714385
130102144
180152194

What each input means

Last Spring Frost (day of year)
Day of year for average last frost (e.g., April 30 = day 120).
First Fall Frost (day of year)
Day of year for average first fall frost (e.g., October 7 = day 280).
Days to Maturity
Days from transplant/sow to harvest (check seed packet).
Cold Hardiness
1=Tender (tomato, pepper), 2=Semi-hardy (lettuce, beet), 3=Hardy (kale, peas).
Indoor Start Weeks
Weeks before transplant to start seeds indoors. 0 for direct-sow crops.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Last Spring Frost (day of year) = 120, First Fall Frost (day of year) = 280, Days to Maturity = 70, Cold Hardiness = 1 = 5 input(s) provided
  2. Calculate Start Seeds Indoors
    Start Seeds Indoors
    92 = 92
  3. Calculate Transplant Day
    Transplant Day
    134 = 134
  4. Calculate Direct Sow Day
    Direct Sow Day
    134 = 134
  5. Calculate Last Planting Day
    Last Planting Day
    210 = 210

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Garden Planning

Succession Planting Calculator

Plan continuous harvests by calculating planting intervals for succession planting throughout the season.

Garden Planning

Garden Yield Calculator

Estimate your garden harvest in pounds, retail value, calories, and meals based on growing conditions.

Garden Planning

Seed Starting Calculator

Find out when to start seeds indoors, when to transplant, and when to expect your harvest based on plant type and last frost date.

Weather & Climate

Frost Date Calculator

Find estimated last spring frost and first fall frost dates by USDA hardiness zone. Plan your garden planting window with confidence.

More in Home, Garden & Maintenance.