Mendel’s Gardens

Sowing planner

Everything below is worked backwards from the day seedlings can go outside.

Your last spring frost

A zip code, or a date if you already know it. The lookup is a static file — nothing is sent anywhere and no service is called.

or

Showing the national default of May 3, which is wrong for most places.

32,883 zip codes, from NOAA's 1991–2020 climate normals matched to the nearest weather station. A station can sit a long way below you: the one used, and how far away it is, are named when you look a zip up.

Species

Leave everything unticked to plan all of them.

For a May 3 2027 last frost, across 4 protocols, earliest first.

Acacia cyanophyllaprotocol 2

N. C. Deno, 1998

Dated steps for Acacia cyanophylla, earliest first, ending at the last frost.
StartStepDetail
Sow and coverTemperature: 70°F 21°C Light: dark
May 3, 2027Plant out

Acacia cyanophyllaprotocol 1

N. C. Deno, 1998

Dated steps for Acacia cyanophylla, earliest first, ending at the last frost.
StartStepDetail
Nick or sand the seed coat
Sow and coverTemperature: 70°F 21°C Light: dark
May 3, 2027Plant out

Actaea rubra

N. C. Deno, 1993

This one takes three seasons. Start in August 2027 to plant out in May 2029.

Too late for spring 2027 — that plan needed starting on August 17, 2025. Here is the plan for 2029.

Dated steps for Actaea rubra, earliest first, ending at the last frost.
StartStepDetail
Clean the flesh off the seed
Leach in running waterDuration: 7 days
Cold moist stratificationDuration: 90 daysTemperature: 40°F 4°C
Warm moist stratificationDuration: 90 daysTemperature: 70°F 21°C
Cold moist stratificationDuration: 90 daysTemperature: 40°F 4°C
Warm moist stratificationDuration: 90 daysTemperature: 70°F 21°C
Cold moist stratificationDuration: 90 daysTemperature: 40°F 4°C
Warm moist stratificationDuration: 90 daysTemperature: 70°F 21°C
Cold moist stratificationTemperature: 40°F 4°C
May 3, 2029Plant out

Actaea pachypoda

N. C. Deno, 1993

This one takes two seasons. Start in August 2027 to plant out in May 2028.

Too late for spring 2027 — that plan needed starting on August 19, 2026. Here is the plan for 2028.

Dated steps for Actaea pachypoda, earliest first, ending at the last frost.
StartStepDetail
Clean the flesh off the seed
Leach in running waterDuration: 7 days
Cold moist stratificationDuration: 90 daysTemperature: 40°F 4°C
Warm moist stratificationDuration: 90 daysTemperature: 70°F 21°C
Cold moist stratificationTemperature: 40°F 4°C
May 3, 2028Plant out

No protocol to plan for Abies alba — the records held are not reviewed yet.