May is the pivot month in zone 3: the average last frost lands around May 15. Hardy crops go out all month; tender ones wait for the far side of that date.
| 🥬 Lettuce | Apr 17 – May 1 | 45–60 days to maturity |
| 🥬 Kale | Apr 17 – May 1 | 55–65 days to maturity |
| 🌈 Swiss Chard | May 1 – May 15 | 50–60 days to maturity |
| 🍃 Collard Greens | Apr 17 – May 1 | 60–75 days to maturity |
| 🥬 Cabbage | Apr 17 – May 1 | 65–85 days to maturity |
| 🥦 Broccoli | Apr 24 – May 8 | 60–75 days to maturity |
| 🥦 Cauliflower | May 1 – May 15 | 60–80 days to maturity |
| 🥬 Brussels Sprouts | May 15 – May 29 | 90–110 days to maturity |
| 🧅 Leeks | Apr 17 – May 1 | 100–120 days to maturity |
| 🥬 Celery | May 15 – May 29 | 100–120 days to maturity |
| 🍅 Tomatoes | May 22 – May 29 | 60–85 days to maturity |
| 🫑 Peppers | May 29 – Jun 5 | 60–90 days to maturity |
| 🍆 Eggplant | May 29 – Jun 5 | 65–80 days to maturity |
| 🍏 Tomatillos | May 22 – May 29 | 70–80 days to maturity |
| 🥒 Cucumbers | May 22 – May 29 | 50–70 days to maturity |
| 🥒 Zucchini | May 22 – May 29 | 45–60 days to maturity |
| 🎃 Winter Squash | May 22 – May 29 | 85–110 days to maturity |
| 🎃 Pumpkins | May 22 – May 29 | 90–110 days to maturity |
| 🍉 Watermelon | May 29 – Jun 5 | 75–95 days to maturity |
| 🍈 Cantaloupe | May 29 – Jun 5 | 75–90 days to maturity |
| 🍠 Sweet Potatoes | May 29 – Jun 12 | 90–120 days to maturity |
| 🌿 Basil | May 22 – May 29 | 30–60 days to maturity |
| 🌿 Parsley | May 1 – May 15 | 70–90 days to maturity |
| 🌱 Chives | May 1 – May 15 | 75–85 days to maturity |
| 🌿 Thyme | May 15 – May 29 | 90–120 days to maturity |
| 🌿 Oregano | May 15 – May 29 | 80–90 days to maturity |
| 🌸 Zinnias | May 22 – May 29 | 60–70 days to maturity |
| 🏵️ Marigolds | May 22 – May 29 | 50–60 days to maturity |
| 🥬 Lettuce | Apr 17 – May 15 | 45–60 days to maturity |
| 🥬 Kale | Apr 17 – May 1 | 55–65 days to maturity |
| 🌈 Swiss Chard | May 1 – May 15 | 50–60 days to maturity |
| 🍃 Collard Greens | May 1 – May 15 | 60–75 days to maturity |
| 🥬 Kohlrabi | Apr 17 – May 1 | 45–60 days to maturity |
| 🥕 Carrots | Apr 24 – May 15 | 60–75 days to maturity |
| 🫒 Beets | Apr 17 – May 1 | 50–65 days to maturity |
| 🥔 Turnips | Apr 17 – May 1 | 40–55 days to maturity |
| 🥕 Parsnips | Apr 24 – May 15 | 100–120 days to maturity |
| 🧅 Onions | Apr 17 – May 1 | 90–110 days to maturity |
| 🧅 Scallions | Apr 17 – May 1 | 60–70 days to maturity |
| 🥔 Potatoes | Apr 17 – May 1 | 70–100 days to maturity |
| 🥬 Bok Choy | Apr 24 – May 8 | 45–55 days to maturity |
| 🌿 Mustard Greens | Apr 17 – May 1 | 35–45 days to maturity |
| 🥒 Cucumbers | May 22 – May 29 | 50–70 days to maturity |
| 🥒 Zucchini | May 22 – May 29 | 45–60 days to maturity |
| 🎃 Winter Squash | May 22 – May 29 | 85–110 days to maturity |
| 🎃 Pumpkins | May 22 – May 29 | 90–110 days to maturity |
| 🍉 Watermelon | May 29 – Jun 5 | 75–95 days to maturity |
| 🍈 Cantaloupe | May 29 – Jun 5 | 75–90 days to maturity |
| 🌽 Sweet Corn | May 22 – May 29 | 65–90 days to maturity |
| 🫘 Green Beans (Bush) | May 22 – May 29 | 50–60 days to maturity |
| 🫘 Pole Beans | May 22 – May 29 | 60–70 days to maturity |
| 🌶️ Okra | May 29 – Jun 12 | 55–65 days to maturity |
| 🌿 Basil | May 29 – Jun 5 | 30–60 days to maturity |
| 🌿 Cilantro | Apr 24 – May 8 | 45–55 days to maturity |
| 🌿 Parsley | May 1 – May 15 | 70–90 days to maturity |
| 🌾 Dill | May 1 – May 15 | 40–55 days to maturity |
| 🌱 Chives | May 1 – May 15 | 75–85 days to maturity |
| 🌻 Sunflowers | May 22 – May 29 | 70–100 days to maturity |
| 🌸 Zinnias | May 22 – May 29 | 60–70 days to maturity |
| 🏵️ Marigolds | May 22 – May 29 | 50–60 days to maturity |
| 🌺 Nasturtiums | May 22 – May 29 | 55–65 days to maturity |
Windows use zone 3's typical frost dates (May 15 / Sep 20). For your own city's dates, run the frost lookup — the planting calendar then localizes everything automatically.
46 crops can go in the ground: lettuce, kale, swiss chard, collard greens, cabbage, broccoli, cauliflower, brussels sprouts, and 38 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 3 (May 22 – May 29).