Zone 4 Planting Dates & Garden Guide Last frost ~May 10, first frost ~Oct 1

Gardening strategy for Zone 4

Zone 4 is where raised beds, a deliberate fall brassica program, and year-round soil cover turn a decent season into a reliable one. The 144 frost-free days between May 10 last frost and October 1 first freeze give you enough runway for main-season tomatoes and 90-day winter squash, but spring soil stays cold and wet long after air temperatures rise — raised beds six to twelve inches high drain faster and warm two weeks sooner than flat ground. Fill them with compost-heavy mix and top with dark mulch or IRT film to push soil past 60 F before you set out warm-season transplants in mid-May. Build your calendar around a fall brassica block: start broccoli, cabbage, and cauliflower indoors in late June, harden them off in July, and transplant into beds vacated by early beans or spring lettuce. Cool September nights improve brassica flavor and cut cabbage-worm pressure compared with spring plantings. Never leave soil bare through the Zone 4 winter. Sow oats or winter rye in late September on empty beds, or mulch heavily with straw and leaves — bare ground erodes during freeze-thaw cycles and bleeds nitrogen before spring planting. Spring peas and spinach go in mid-April, a month before last frost. Tomatoes and peppers started indoors in March transplant after May 10. When September forecasts trend toward frost, clear frost-tender crops first, then let kale and roots continue under a lightweight row cover until hard freeze.

Tips for Zone 4 gardeners

• Build raised beds with compost-rich soil — they warm faster and drain spring mud weeks before flat ground in Zone 4.
• Start fall broccoli and cabbage transplants indoors in late June for harvest in September before the October 1 average first frost.
• Sow a winter cover crop like oats or rye by late September on any bed not growing garlic — bare soil erodes over the long cold season.