The best time of year to plant vegetables varies based on what you grow. Cool season crops go in 2-6 weeks before your last spring frost while warm season crops wait until 1-2 weeks after frost danger passes. Fall plantings need to start 8-12 weeks before your first frost to mature in time.
I used to guess at planting dates and lost many crops to frost or heat before I learned to use a calendar. Now I mark my frost dates and count backward from there to plan every planting. A cheap soil thermometer helped me stop planting seeds in ground too cold to sprout them.
When to start planting vegetables depends on your local frost dates and soil conditions. I check soil temp at 2-3 inches deep before sowing any seeds. Cool season crops sprout once soil stays above 40°F (4°C) for a week. Warm season seeds need soil at 60°F (16°C) or higher.
Your vegetable planting schedule should follow this pattern for spring. Plant peas, spinach, and lettuce 4-6 weeks before the last frost. Add broccoli and cabbage transplants 2-4 weeks before frost. Wait until after frost danger for tomatoes, peppers, and squash since cold kills them fast.
Regional variations affect your timing even within the same state. Iowa State Extension notes that southern areas of a state can plant about one week earlier than central areas. Northern regions should wait one week longer than average dates suggest. Microclimates in your own yard matter too.
Fall planting requires backward math from your first expected frost. Find the days to maturity on your seed packet and count back from frost date. Add 10-14 extra days since plants grow slower as daylight decreases in autumn. This cushion prevents the disappointment of crops that almost reach harvest.
Succession planting extends your harvest window for fast-maturing crops. Plant lettuce every two weeks from early spring through mid-summer for continuous salads. Do the same in late summer through early fall. Radishes, spinach, and beans all benefit from staggered planting dates too.
Find your local frost dates through your county extension office or online databases. The USDA Plant Hardiness Zone Map helps but frost dates matter more for vegetable timing. Average last spring frost and first fall frost dates tell you when to plant better than zone numbers alone.
Keep a garden journal to track what works in your specific spot. Record planting dates, harvest dates, and weather each year. After a few seasons, you build a custom vegetable planting schedule. Your own records beat any generic guide out there.
Read the full article: Cool Season Vegetables: Complete Growing Guide
