In the challenging climate of Zone 4, gardening is a race against time. With a tight window between the last spring frost and the first autumn freeze, every single day counts. This Zone 4 guide is specifically designed for this reality, offering two distinct timelines: an ‘Aggressive’ schedule to push the limits of our short season, and a ‘Safe’ schedule to guarantee a rewarding harvest. Find the perfect dates for your gardening style below.
Key Dates for Zone 4
Understanding the frost patterns in your area is fundamental to successful gardening. Here are the key baseline dates I use to create your planting calendar, offering both an early-start (“Aggressive”) and a safer approach:
Spring Planting Baselines
- Aggressive Spring Planting Baseline: May 9th
- Safe Spring Planting Baseline: May 15th
Fall Planting Baselines
- Aggressive Fall Planting Baseline: September 30th
- Safe Fall Planting Baseline: September 25th
Note: The “Aggressive” fall date is later because it aims to maximize the growing season, accepting a higher risk of an early frost.
The USDA Zone 4 Planting Calendar
This comprehensive calendar provides specific planting windows for a variety of common vegetables, taking into account both my Aggressive and Safe spring and fall planting baselines.
How to Use This Calendar
This calendar provides key planting dates for two gardening styles—Aggressive and Safe—to suit your tolerance for risk. The logic for spring and fall planting is different, so please read the descriptions below.
For Spring Planting:
- Safe: For gardeners who prefer a cautious approach. This means planting later to ensure minimal risk of frost damage to new seedlings from a late spring frost.
- Aggressive: For gardeners who want to get a head start. This involves planting earlier and being prepared to protect young plants from potential late frosts.
For Fall Planting:
Aggressive: For gardeners who want to maximize their harvest. This involves planting later to extend the growing season as long as possible, while being prepared to protect plants from an unexpected early frost.
Safe: For gardeners who prioritize a guaranteed harvest. This means planting earlier in the season to ensure crops are fully mature before the first frost of autumn arrives.
| Vegetable | Planting Method | Spring Planting (Aggressive) | Spring Planting (Safe) | Fall Planting (Aggressive) | Fall Planting (Safe) | Days to Harvest (days) | Notes |
| Radishes | Direct Sow Only | Mar 28 – Apr 11 | Apr 3 – Apr 17 | Aug 19 – Sep 2 | Aug 14 – Aug 28 | 21-35 | Cool-season crop; requires loose soil. For continuous harvest, sow every 1-2 weeks until weather warms. |
| Lettuce | Direct sow or start seeds indoors | Apr 11 – Apr 25 | Apr 17 – May 1 | Jul 22 – Aug 5 | Jul 17 – Jul 31 | 45−60 | For spring planting, you can direct sow on this date. To get a head start, start seeds indoors 3-4 weeks before this date for transplanting. |
| Bush Beans | Direct Sow Only | May 16 – May 23 | May 22 – May 29 | Jun 24 – Jul 8 | Jun 19 – Jul 3 | 50-60 | Warm-season crop; direct sow after frost. No support needed. |
| Zucchini | Direct Sow (recommended) | May 16 – May 23 | May 22 – May 29 | N/A | N/A | 45-60 | For an earlier harvest, start seeds indoors 2-4 weeks so they are ready to transplant on the ‘Safe’ planting date. |
| Tomatoes | Start indoors, then transplant | May 16 – May 23 | May 22 – May 29 | N/A | N/A | 50-90+ | Dates are for transplanting outdoors. Start seeds indoors 6-8 weeks prior. |
| Peas | Direct Sow Recommended (Can start indoors) | Mar 28 – Apr 11 | Apr 3 – Apr 17 | Jul 22 – Aug 5 | Jul 17 – Jul 31 | 55-70 | Frost-hardy: plant early & provide a trellis. Harvest daily to maximize yield before summer heat ends the season. |
| Spinach | Direct Sow (recommended) | Mar 28 – Apr 11 | Apr 3 – Apr 17 | Aug 5 – Aug 19 | Jul 31 – Aug 14 | 40-60 | Very cold-hardy; plant early. Keep soil moist to prevent bitterness. Harvest outer leaves for a continuous supply before summer heat arrives. |
| Kale | Direct sow or start seeds indoors | Apr 11 – Apr 25 | Apr 17 – May 1 | Jul 2 – Aug 1 | Jun 27 – Jul 27 | 55-75 | Very cold-hardy. Frost improves flavor, making fall harvests sweeter. Harvest outer leaves to allow the plant to keep producing. |
| Basil | Start Indoors or Direct Sow | May 16 – May 23 | May 22 – May 29 | Jul 8 – Jul 22 | Jul 3 – Jul 17 | 60-75 | Spring date is for transplanting; start seeds indoors 6-8 weeks prior. Fall date is for direct sowing. |
| Mint | Transplants or Cuttings | Apr 25 – May 9 | May 1 – May 15 | Aug 5 – Aug 19 | Jul 31 – Aug 14 | 30-40 | Dates are for transplants (not seed). Harvest continuously once established. |
| Garlic | Direct Sow Only | Apr 11 – Apr 25 | Apr 17 – May 1 | Aug 19 – Sep 2 | Aug 14 – Aug 28 | ~270 | Plant from cloves; harvest time shown is for fall planting. Fall planting is strongly recommended. Use Hardneck cloves & apply a thick winter mulch (4-6″). Spring planting yields much smaller, often undivided bulbs. |
✔ Accuracy is my priority. The key planting dates in this calendar are calculated based on representative Aggressive and Safe frost date baselines established for each zone. Because your garden’s microclimate may vary, I strongly recommend that you verify your local frost dates for the most accurate timing. Learn My Methodology & Find a Frost Date Tool Here.
The Science Behind My Calendars
My calendars are built upon a rigorous, data-driven process. By analyzing historical frost data for several populous and representative cities within each USDA zone, I establish both an average and a conservative “safe” frost date. This ensures the planting windows you see here are both accurate and reliable.
To see the full list of cities and data points used in my research, please visit the My Research Data page. For a complete explanation of the calculation process, you can read about My Methodology.
Your Next Step: Learn How to Grow
Now that you know when to plant in Zone 4, the next step is learning how to grow each vegetable from seed to a successful harvest.
My complete guides provide detailed, step-by-step instructions for everything you’ll need. Explore the full library to turn this calendar into a thriving, productive garden.
