Getting started
Sowing and space
Use vigorous transplants timed so head development avoids the strongest heat and severe cold.
Allow about 13.8 in (35 cm) of usable depth and roughly 19.7 in (50 cm) between plants.
Watering reference: frequent and even. Adjust to rain, heat, wind, growth stage and container volume.
Planting windows by broad profile
These original editorial windows compare thermal groups, not live weather. Check current frost, heat, rainfall and packet directions.
Very cold, short season
Use actual frost-free conditions, soil temperature, and short-season cultivars; a listed month alone is not enough.
Cold winter, warm summer
Local last and first frost, lake effects, elevation, and urban heat can move the usable window by weeks.
Match cultivar maturity to the available spring or fall cool period.
Hot and humid
Favor cool crops outside peak heat and protect warm crops from the last local freeze rather than following the month alone.
A narrow cool-season window and heat spikes can disrupt heading.
Mild marine
Watch soil warmth, drainage, direct sun, and local wind; inland valleys can differ markedly from the coast.
Dry summer, mild winter
Use cool months for leafy crops and account for heat waves, wildfire smoke, irrigation rules, and local frost pockets.
Arid or high desert
Treat windows as irrigated-garden references and verify elevation, frost, extreme heat, wind, and current water rules.
Tropical or frost-light
Choose timing around local rainfall, disease pressure, storms, and heat; high-elevation tropical sites may belong elsewhere.
Practical care
- Maintain even moisture and adequate root volume.
- Inspect the growing point without damaging it.
Points to check
- Stress can cause small or malformed heads.
- If pest control is needed, use only a correctly labeled product.
Provenance and confidence
This rule is an original editorial synthesis and no independent local agronomic review is claimed.
United States home food garden editorial synthesis — version 1
Global Garden Planner
Original seven-profile model and localized corpus. It remains an editorial draft until an independent U.S. agronomic review is recorded.
2023 USDA Plant Hardiness Zone Map — map creation and interpretation
United States Department of Agriculture, Agricultural Research Service
Supports treating average annual extreme minimum temperature as one cold-risk reference, not a complete planting calendar or current forecast.
U.S. Climate Normals
NOAA National Centers for Environmental Information
Supports the use of long-period climate context and the warning that station and regional conditions vary; it does not supply operational month rows.
Vegetable Gardening
USDA National Agricultural Library
Supports the planning sequence of site selection, soil or mix preparation, planting, maintenance, and harvest, plus referral to Cooperative Extension.
Introduction to pesticide labels
United States Environmental Protection Agency
Supports the instruction to use a registered product only in a manner consistent with its complete labeling; the project does not prescribe pesticides.
Use it in context
A month alone cannot resolve cultivar, soil, microclimate or a current extreme.
Use reputable planting material. Use reputable domestic seed or plants and check current USDA APHIS and state restrictions before moving or importing plant material.
If a pesticide is considered, use only a product registered for the site and crop and follow the complete EPA-approved label and applicable state requirements.