May is the pivot month in zone 4: the average last frost lands around May 5. Hardy crops go out all month; tender ones wait for the far side of that date.
| 🌈 Swiss Chard | Apr 21 – May 5 | 50–60 days to maturity |
| 🥦 Cauliflower | Apr 21 – May 5 | 60–80 days to maturity |
| 🥬 Brussels Sprouts | May 5 – May 19 | 90–110 days to maturity |
| 🥬 Celery | May 5 – May 19 | 100–120 days to maturity |
| 🍅 Tomatoes | May 12 – May 19 | 60–85 days to maturity |
| 🫑 Peppers | May 19 – May 26 | 60–90 days to maturity |
| 🍆 Eggplant | May 19 – May 26 | 65–80 days to maturity |
| 🍏 Tomatillos | May 12 – May 19 | 70–80 days to maturity |
| 🥒 Cucumbers | May 12 – May 19 | 50–70 days to maturity |
| 🥒 Zucchini | May 12 – May 19 | 45–60 days to maturity |
| 🎃 Winter Squash | May 12 – May 19 | 85–110 days to maturity |
| 🎃 Pumpkins | May 12 – May 19 | 90–110 days to maturity |
| 🍉 Watermelon | May 19 – May 26 | 75–95 days to maturity |
| 🍈 Cantaloupe | May 19 – May 26 | 75–90 days to maturity |
| 🌶️ Okra | May 26 – Jun 2 | 55–65 days to maturity |
| 🍠 Sweet Potatoes | May 19 – Jun 2 | 90–120 days to maturity |
| 🌿 Basil | May 12 – May 19 | 30–60 days to maturity |
| 🌿 Parsley | Apr 21 – May 5 | 70–90 days to maturity |
| 🌱 Chives | Apr 21 – May 5 | 75–85 days to maturity |
| 🌿 Thyme | May 5 – May 19 | 90–120 days to maturity |
| 🌿 Oregano | May 5 – May 19 | 80–90 days to maturity |
| 🌸 Zinnias | May 12 – May 19 | 60–70 days to maturity |
| 🏵️ Marigolds | May 12 – May 19 | 50–60 days to maturity |
| 🥬 Lettuce | Apr 7 – May 5 | 45–60 days to maturity |
| 🌈 Swiss Chard | Apr 21 – May 5 | 50–60 days to maturity |
| 🍃 Collard Greens | Apr 21 – May 5 | 60–75 days to maturity |
| 🥕 Carrots | Apr 14 – May 5 | 60–75 days to maturity |
| 🥕 Parsnips | Apr 14 – May 5 | 100–120 days to maturity |
| 🥒 Cucumbers | May 12 – May 19 | 50–70 days to maturity |
| 🥒 Zucchini | May 12 – May 19 | 45–60 days to maturity |
| 🎃 Winter Squash | May 12 – May 19 | 85–110 days to maturity |
| 🎃 Pumpkins | May 12 – May 19 | 90–110 days to maturity |
| 🍉 Watermelon | May 19 – May 26 | 75–95 days to maturity |
| 🍈 Cantaloupe | May 19 – May 26 | 75–90 days to maturity |
| 🌽 Sweet Corn | May 12 – May 19 | 65–90 days to maturity |
| 🫘 Green Beans (Bush) | May 12 – May 19 | 50–60 days to maturity |
| 🫘 Pole Beans | May 12 – May 19 | 60–70 days to maturity |
| 🌶️ Okra | May 19 – Jun 2 | 55–65 days to maturity |
| 🌿 Basil | May 19 – May 26 | 30–60 days to maturity |
| 🌿 Parsley | Apr 21 – May 5 | 70–90 days to maturity |
| 🌾 Dill | Apr 21 – May 5 | 40–55 days to maturity |
| 🌱 Chives | Apr 21 – May 5 | 75–85 days to maturity |
| 🌻 Sunflowers | May 12 – May 19 | 70–100 days to maturity |
| 🌸 Zinnias | May 12 – May 19 | 60–70 days to maturity |
| 🏵️ Marigolds | May 12 – May 19 | 50–60 days to maturity |
| 🌺 Nasturtiums | May 12 – May 19 | 55–65 days to maturity |
Windows use zone 4's typical frost dates (May 5 / Oct 1). For your own city's dates, run the frost lookup — the planting calendar then localizes everything automatically.
33 crops can go in the ground: swiss chard, cauliflower, brussels sprouts, celery, tomatoes, peppers, eggplant, tomatillos, and 25 more. Exact windows are in the tables above — early and late in the month can differ by a full frost date.
Yes — May is tomato transplanting time in zone 4 (May 12 – May 19).