Frost Dates & Planting Calendar for Mercerville-Hamilton Square, NJ
Plan your garden around Mercerville-Hamilton Square, NJ's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
April 25
Safe May 12
Typical Apr 25
Risky Apr 12
First Fall Frost
October 16
Safe Oct 4
Typical Oct 16
Risky Oct 29
Growing Season
173 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 7a
Mild winters and a long growing season, room for both cool- and warm-season crops.
Data: NOAA station HIGHTSTOWN 2 W, NJ US, 10 km away.
—
days until the typical last spring frost
Monthly Temperatures
Avg. high
Avg. temp
Avg. low
Planting Calendar
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Tomato | Feb 28 – Mar 14 | — | May 2 – May 9 | — | 60–85 days | Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed. |
| Pepper | Feb 14 – Feb 28 | — | May 2 – May 16 | — | 60–90 days | Slow to germinate; start indoors 8-10 weeks before last frost. Transplant only once nights stay above 55F, 1-3 weeks after last frost. |
| Eggplant | Feb 14 – Feb 28 | — | May 9 – May 16 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Mar 28 – Apr 4 | May 2 – May 9 | May 2 – May 9 | — | 50–65 days | Can be started indoors 3-4 weeks before transplanting, or direct-sown 1-2 weeks after last frost once soil is warm. |
| Zucchini | Apr 4 – Apr 11 | May 2 – May 16 | May 2 – May 9 | — | 45–55 days | Fast-growing squash; direct sow 1-3 weeks after last frost, or start indoors 2-3 weeks early for a head start. |
| Winter Squash | Mar 28 – Apr 4 | May 2 – May 16 | May 2 – May 9 | — | 80–110 days | Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates. |
| Pumpkin | — | May 2 – May 16 | — | — | 90–120 days | Direct sow 1-3 weeks after last frost; back-time from your first fall frost so the 90-120 day maturity window lands before it. |
| Watermelon | Mar 28 – Apr 4 | — | May 9 – May 16 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Mar 28 – Apr 4 | — | May 9 – May 16 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | Apr 25 – May 9 | — | — | 60–100 days | Direct sow at last frost to 2 weeks after, once soil reaches 60F; does not transplant well. Succession sow every 2 weeks. |
| Green Bean | — | Apr 25 – May 9 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Mar 14 – Mar 28 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Mar 28 – Apr 11 | — | Aug 21 – Sep 4 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Mar 14 – Mar 28 | — | Aug 21 – Sep 4 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Mar 28 – Apr 11 | — | Aug 7 – Aug 21 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Mar 28 – Apr 11 | — | Sep 4 – Sep 11 | 30–40 days | Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks. |
| Swiss Chard | — | Apr 4 – Apr 18 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Mar 7 – Mar 21 | — | Apr 4 – Apr 11 | Aug 14 – Aug 21 | 55–80 days | Start indoors 5-7 weeks before last frost; transplant out 2-3 weeks before last frost (hardens off to light frost). |
| Cauliflower | Mar 7 – Mar 21 | — | Apr 11 – Apr 18 | Aug 7 – Aug 14 | 55–85 days | Fussier than broccoli about temperature swings; start indoors 5-7 weeks before last frost, transplant 1-2 weeks before last frost. |
| Cabbage | Mar 7 – Mar 21 | — | Mar 28 – Apr 11 | Aug 7 – Aug 21 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Mar 7 – Mar 21 | — | Apr 4 – Apr 18 | — | 90–110 days | Long-season crop best timed to mature after a light fall frost for sweetest flavor; start indoors 5-7 weeks before last frost. |
| Carrot | — | Mar 28 – Apr 11 | — | Jul 24 – Aug 7 | 60–80 days | Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked. |
| Beet | — | Mar 28 – Apr 11 | — | Aug 7 – Aug 21 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Mar 21 – Apr 4 | — | Sep 4 – Sep 18 | 22–30 days | Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked. |
| Turnip | — | Mar 28 – Apr 11 | — | Aug 7 – Aug 21 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Feb 14 – Feb 28 | — | Mar 28 – Apr 11 | — | 90–120 days | Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings. |
| Garlic | — | — | — | Sep 18 – Oct 2 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Mar 28 – Apr 11 | — | — | 70–120 days | Plant seed potatoes 2-4 weeks before last frost, as soon as soil can be worked and is above 45F; light frost on emerging foliage is usually tolerated. |
| Sweet Potato | — | — | May 9 – May 23 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Mar 28 – Apr 11 | — | 730–1095 days | Perennial; plant crowns 2-4 weeks before last frost as soon as soil can be worked. Takes 2-3 years to full production. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Basil | Mar 14 – Mar 21 | — | May 2 – May 9 | — | 50–70 days | Very frost/cold sensitive; start indoors 5-6 weeks before last frost, transplant only after all danger of frost (1-2 weeks after) and nights stay warm. |
| Cilantro | — | Apr 4 – Apr 18 | — | Aug 21 – Sep 4 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Feb 28 – Mar 14 | — | Apr 11 – Apr 18 | — | 70–90 days | Slow to germinate; start indoors 6-8 weeks before last frost, transplant 1-2 weeks before last frost (biennial, cold-tolerant). |
| Dill | — | Apr 4 – Apr 18 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Feb 28 – Mar 14 | — | Apr 25 – May 2 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Feb 28 – Mar 14 | — | Apr 25 – May 2 | — | 85–95 days | Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Sunflower | — | May 2 – May 16 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Mar 28 – Apr 4 | May 2 – May 16 | May 2 – May 9 | — | 60–70 days | Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms. |
| Marigold | Mar 14 – Mar 28 | — | May 2 – May 9 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Mar 28 – Apr 4 | May 2 – May 16 | May 2 – May 9 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | May 2 – May 16 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | May 2 – May 16 | — | 90–120 days | Plant tubers 1-3 weeks after last frost once soil is warm (60F+); very frost-sensitive. |
Date ranges are estimates based on university extension guidelines and this city's NOAA frost normals — not a guarantee. Scroll to see all columns on narrow screens.
Frequently Asked Questions
When is the last frost in Mercerville-Hamilton Square, NJ?
Based on 1991–2020 NOAA climate normals for the HIGHTSTOWN 2 W, NJ US station, the last spring frost in Mercerville-Hamilton Square typically falls around April 25. A cautious gardener might wait until May 12 (only a 10% chance of a later frost), while April 12 marks an earlier, higher-risk planting date.
When is the first frost in Mercerville-Hamilton Square, NJ in fall?
The first fall frost in Mercerville-Hamilton Square typically arrives around October 16. To stay safe, assume frost could start as early as October 4; in milder years it can hold off until October 29.
How long is the growing season in Mercerville-Hamilton Square, NJ?
Mercerville-Hamilton Square's average frost-free growing season is about 173 days, running from the typical last spring frost (April 25) to the typical first fall frost (October 16).
What USDA hardiness zone is Mercerville-Hamilton Square, NJ in?
Mercerville-Hamilton Square, NJ is in USDA plant hardiness zone 7a, per the USDA's 2023 Plant Hardiness Zone Map. Mild winters and a long growing season, room for both cool- and warm-season crops.