Henefer, UT planting calendar
- USDA zone
- 6a−10 to −5 °F
- Last frost
- May 30avg, 32°F
- First frost
- Sep 18avg, 32°F
- Growing season
- 112days
Henefer, Utah is in USDA plant hardiness zone 6a. Its average last spring frost is around May 30 and the first fall frost around September 18, giving a growing season of about 112 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Henefer planting calendar
Each crop's windows are counted from Henefer's average frost dates. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Apr 4 – Apr 18 | Jun 6 – Jun 13 | Aug 5 – Aug 25 | — |
| Pepper | Very tender | Mar 21 – Apr 4 | Jun 13 – Jun 20 | Aug 12 – Sep 11 | — |
| Cucumber | Tender | May 2 – May 9 | Jun 6 – Jun 13 | Jul 26 – Aug 15 | — |
| Summer squash / zucchini | Tender | — | Jun 6 – Jun 13 | Jul 21 – Aug 5 | — |
| Bush bean | Tender | — | Jun 6 – Jun 13 | Jul 26 – Aug 5 | Jul 20 – Jul 30 |
| Sweet corn | Tender | — | May 30 – Jun 13 | Jul 29 – Aug 28 | — |
| Basil | Very tender | Apr 18 – May 2 | Jun 6 – Jun 13 | Jul 6 – Jul 21 | — |
| Lettuce | Half-hardy | Apr 18 – May 2 | May 2 – May 16 | Jun 16 – Jul 1 | Jul 6 – Jul 21 |
| Pea | Hardy | — | Apr 18 – May 2 | Jun 12 – Jun 27 | Jun 26 – Jul 11 |
| Spinach | Hardy | — | Apr 18 – May 2 | May 28 – Jun 7 | Jul 16 – Jul 26 |
| Carrot | Half-hardy | — | May 9 – May 16 | Jul 8 – Jul 28 | Jun 16 – Jul 6 |
| Broccoli | Half-hardy | Apr 4 – Apr 18 | May 2 – May 16 | Jun 26 – Jul 16 | Jun 21 – Jul 11 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USC00422385. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 (p10 for spring, p90 for fall) — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Jun 15 | Jun 30 | Sep 8 | Sep 22 | 83 |
| 32°F (freeze) | May 30 | Jun 16 | Sep 18 | Oct 1 | 112 |
| 28°F | May 10 | May 31 | Oct 1 | Oct 14 | 141 |
| 24°F | Apr 26 | May 13 | Oct 11 | Oct 26 | 169 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,091 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,050 | cool-season crops (brassicas, greens) |
Hardiness zone 6a
Henefer sits in USDA plant hardiness zone 6a on the 2023 map — meaning its average annual extreme minimum winter temperature is about −10 to −5 °F. That number tells you which perennials, shrubs, and trees reliably survive an average winter here; it does not set your planting dates, which come from the frost calendar above.
Explore more places in zone 6a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Henefer?
- Henefer, Utah is in USDA plant hardiness zone 6a on the 2023 map (average annual extreme minimum temperature −10 to −5 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Henefer?
- The average (median) last spring frost at 32°F is around May 30, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as June 16, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Henefer?
- The average first fall frost at 32°F is around September 18. That leaves a growing season of about 112 days between the average last spring and first fall frosts.
- When should I start tomatoes in Henefer?
- Start tomato seeds indoors about Apr 4 – Apr 18 and transplant them outside about Jun 6 – Jun 13, once the danger of frost has passed. Estimated first harvest is around Aug 5 – Aug 25.
- How long is the growing season in Henefer?
- About 112 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~May 30) and the average first fall frost (~September 18). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USC00422385 (Echo Dam, 4.8 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.