Frost Dates & Planting Calendar for Vernal, UT
Plan your garden around Vernal, UT's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
May 7
Safe May 28
Typical May 7
Risky Apr 24
First Fall Frost
October 6
Safe Sep 23
Typical Oct 6
Risky Oct 20
Growing Season
150 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 6a
A classic four-season climate with cold winters and a solid summer growing season.
Data: NOAA station VERNAL, UT US, 1.8 km away.
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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 | Mar 12 – Mar 26 | — | May 14 – May 21 | — | 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 26 – Mar 12 | — | May 14 – May 28 | — | 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 26 – Mar 12 | — | May 21 – May 28 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Apr 9 – Apr 16 | May 14 – May 21 | May 14 – May 21 | — | 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 16 – Apr 23 | May 14 – May 28 | May 14 – May 21 | — | 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 | Apr 9 – Apr 16 | May 14 – May 28 | May 14 – May 21 | — | 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 14 – May 28 | — | — | 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 | Apr 9 – Apr 16 | — | May 21 – May 28 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Apr 9 – Apr 16 | — | May 21 – May 28 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | May 7 – May 21 | — | — | 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 | — | May 7 – May 21 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Mar 26 – Apr 9 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Apr 9 – Apr 23 | — | Aug 11 – Aug 25 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Mar 26 – Apr 9 | — | Aug 11 – Aug 25 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Apr 9 – Apr 23 | — | Jul 28 – Aug 11 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Apr 9 – Apr 23 | — | Aug 25 – Sep 1 | 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 16 – Apr 30 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Mar 19 – Apr 2 | — | Apr 16 – Apr 23 | Aug 4 – Aug 11 | 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 19 – Apr 2 | — | Apr 23 – Apr 30 | Jul 28 – Aug 4 | 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 19 – Apr 2 | — | Apr 9 – Apr 23 | Jul 28 – Aug 11 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Mar 19 – Apr 2 | — | Apr 16 – Apr 30 | — | 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 | — | Apr 9 – Apr 23 | — | Jul 14 – Jul 28 | 60–80 days | Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked. |
| Beet | — | Apr 9 – Apr 23 | — | Jul 28 – Aug 11 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Apr 2 – Apr 16 | — | Aug 25 – Sep 8 | 22–30 days | Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked. |
| Turnip | — | Apr 9 – Apr 23 | — | Jul 28 – Aug 11 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Feb 26 – Mar 12 | — | Apr 9 – Apr 23 | — | 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 8 – Sep 22 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Apr 9 – Apr 23 | — | — | 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 21 – Jun 4 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Apr 9 – Apr 23 | — | 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 26 – Apr 2 | — | May 14 – May 21 | — | 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 16 – Apr 30 | — | Aug 11 – Aug 25 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Mar 12 – Mar 26 | — | Apr 23 – Apr 30 | — | 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 16 – Apr 30 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Mar 12 – Mar 26 | — | May 7 – May 14 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Mar 12 – Mar 26 | — | May 7 – May 14 | — | 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 14 – May 28 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Apr 9 – Apr 16 | May 14 – May 28 | May 14 – May 21 | — | 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 26 – Apr 9 | — | May 14 – May 21 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Apr 9 – Apr 16 | May 14 – May 28 | May 14 – May 21 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | May 14 – May 28 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | May 14 – May 28 | — | 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 Vernal, UT?
Based on 1991–2020 NOAA climate normals for the VERNAL, UT US station, the last spring frost in Vernal typically falls around May 7. A cautious gardener might wait until May 28 (only a 10% chance of a later frost), while April 24 marks an earlier, higher-risk planting date.
When is the first frost in Vernal, UT in fall?
The first fall frost in Vernal typically arrives around October 6. To stay safe, assume frost could start as early as September 23; in milder years it can hold off until October 20.
How long is the growing season in Vernal, UT?
Vernal's average frost-free growing season is about 150 days, running from the typical last spring frost (May 7) to the typical first fall frost (October 6).
What USDA hardiness zone is Vernal, UT in?
Vernal, UT is in USDA plant hardiness zone 6a, per the USDA's 2023 Plant Hardiness Zone Map. A classic four-season climate with cold winters and a solid summer growing season.