Planning tool

Soil Temperature Germination Planner

Use the catalog germination range on each seed entry as a go/no-go check before direct sowing outdoors, starting seeds indoors, or transplanting into cold beds.

Inputs

Soil temperature reading
Measure the bed with a soil thermometer placed about 4 inches deep, then compare that reading with local frost risk and the seed catalog range.
Catalog germination range
Each seed entry stores a low and high germination temperature so cold-soil and hot-soil mismatches are visible before planting.
Start method
Direct sowing depends on outdoor soil warmth; indoor starts depend on warm growing medium before hardening and transplant timing.
Season and frost context
Cool-season entries tolerate colder starts better than warm-season entries, but frost risk and local forecasts still control outdoor planting.

What it returns

Planning guidance

Field reading
Use a soil thermometer placed about 4 inches deep, then compare the reading with the catalog range instead of planting by calendar date alone.
Minimum threshold
Plant when soils reach minimum temperature measured at 8 a.m., 4 inches deep; CSU notes beans are measured deeper than most entries.
Cool-season start
Early cool-season crops can use 40-50F soil when beds are workable, but check frost forecasts before treating cold tolerance as complete safety.
Moderate warmth
Moderately warm-season crops often establish better once soil reaches 55-60F, especially when roots need stronger early growth.
Warm-season wait
Heat-loving crops should wait for 65F or warmer soil and passed frost risk before outdoor planting.
Indoor-start caveat
Indoor trays need moist growing medium, steady warmth, and light after germination; a germination range is not a transplant date.

Regional soil-temperature fallback

Cool-soil candidates

Warm-soil candidates

Supporting planning paths

Source basis