August is the closing stretch of zone 4's season — the average first frost (Oct 1) is only weeks past month's end, so this is fall-sowing and garlic-planting territory.
| 🫛 Peas | Jul 23 – Aug 6 | 55–70 days to maturity |
| 🥬 Lettuce | Aug 6 – Sep 3 | 45–60 days to maturity |
| 🍃 Spinach | Aug 6 – Aug 20 | 40–50 days to maturity |
| 🌿 Arugula | Aug 20 – Sep 3 | 30–40 days to maturity |
| 🌈 Swiss Chard | Jul 23 – Aug 6 | 50–60 days to maturity |
| 🥬 Kohlrabi | Jul 23 – Aug 6 | 45–60 days to maturity |
| 🫒 Beets | Jul 23 – Aug 6 | 50–65 days to maturity |
| 🌶️ Radishes | Aug 20 – Sep 3 | 22–30 days to maturity |
| 🥔 Turnips | Jul 23 – Aug 6 | 40–55 days to maturity |
| 🧅 Scallions | Aug 6 – Aug 20 | 60–70 days to maturity |
| 🧄 Garlic | Aug 20 – Sep 17 | plant cloves; harvest next summer |
| 🥬 Bok Choy | Aug 6 – Aug 20 | 45–55 days to maturity |
| 🌿 Mustard Greens | Aug 6 – Aug 20 | 35–45 days to maturity |
| 🫘 Green Beans (Bush) | Jul 23 – Aug 6 | 50–60 days to maturity |
| 🌿 Cilantro | Aug 6 – Aug 20 | 45–55 days to maturity |
| 🌾 Dill | Aug 6 – Aug 20 | 40–55 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.
16 crops can go in the ground: peas, lettuce, spinach, arugula, swiss chard, kohlrabi, beets, radishes, and 8 more. Exact windows are in the tables above — early and late in the month can differ by a full frost date.
The spring window has passed; tomatoes set out this late won't beat the Oct 1 average first frost to ripeness. Plan for next spring's seed-starting instead.