Frost Dates for Glenwood Springs, CO 81601
Last spring frost May 25 · First fall frost September 24 · 122 frost-free days · USDA Zone 6a
ZIP 81601 has about 16,800 people.
Moderate season: 122 frost-free days. Spring frost risk spans May 7–June 13 (37 days). Fall frost risk spans September 11–October 6 (25 days).
Frost probability for 81601
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | June 13 | May 25 | May 7 |
| Fall (first frost) | September 11 | September 24 | October 6 |
Dates come from NOAA 1971–2000 freeze probabilities at RIFLE (39.6 km away); the 50% date is the median year.
Which crops fit a 122-day season in Glenwood Springs
In Glenwood Springs (122 frost-free days, a moderate season), 35 of 56 planner crops fit outright, 15 get two plantings, 5 need an indoor start, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 20 | Jun 8–Jun 15 | 80 | fits: 80 days to maturity, 80 available after Jun 8. | — |
| Pepper | Apr 13 | Jun 8–Jun 15 | 80 | fits: 75 days to maturity, 80 available after Jun 8. | — |
| Lettuce | Mar 30 | Apr 27–May 4 | 157 | two-plantings: Plant Apr 27 and again by Aug 3; both mature before Oct 1. | Aug 3 |
| Carrots | — | May 4–May 11 | 164 | fits: 70 days to maturity, 164 available after May 4. | Jul 23 |
| Cucumber | May 4 | Jun 8–Jun 15 | 94 | fits: 60 days to maturity, 94 available after Jun 8. | Jun 28 |
| Beans | — | Jun 1–Jun 15 | 108 | fits: 60 days to maturity, 108 available after Jun 1. | Jul 5 |
| Peas | — | Mar 30–Jun 8 | 185 | fits: 65 days to maturity, 185 available after Mar 30. | Jul 14 |
| Zucchini | May 11 | Jun 8–Jun 15 | 94 | fits: 55 days to maturity, 94 available after Jun 8. | Jul 3 |
| Onion | Mar 2 | Apr 27–May 11 | 157 | fits: 100 days to maturity, 157 available after Apr 27. | — |
| Spinach | — | Mar 30–May 18 | 199 | two-plantings: Plant Mar 30 and again by Aug 22; both mature before Oct 15. | Aug 22 |
| Kale | Mar 16 | Apr 27–May 11 | 171 | two-plantings: Plant Apr 27 and again by Aug 7; both mature before Oct 15. | Aug 7 |
| Broccoli | Mar 30 | Apr 27–May 11 | 157 | fits: 80 days to maturity, 157 available after Apr 27. | Jun 29 |
| Cabbage | Mar 30 | Apr 27–May 11 | 171 | fits: 70 days to maturity, 171 available after Apr 27. | Jul 23 |
| Radish | — | Mar 30–Jun 22 | 185 | two-plantings: Plant Mar 30 and again by Aug 23; both mature before Oct 1. | Aug 23 |
| Beets | — | Mar 30–Jun 22 | 185 | two-plantings: Plant Mar 30 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Potatoes | — | May 11–May 18 | 143 | fits: 90 days to maturity, 143 available after May 11. | — |
| Garlic | — | Sep 24 | 227 | overwinter: Plant Sep 24 to Oct 15; harvest the following summer. | Oct 15 |
| Strawberry | — | Apr 20–Jun 15 | 178 | perennial: A perennial: plant Apr 20; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 27 | Jun 1–Jun 8 | 94 | fits: 75 days to maturity, 94 available after Jun 1. | Jun 6 |
| Pumpkin | May 11 | Jun 8–Jun 8 | 87 | head-start: Even planted out Jun 8, the outdoor season is about 13 days short; choose an early variety or grow under cover. | — |
| Cauliflower | Apr 13 | May 18–Jun 1 | 136 | fits: 75 days to maturity, 136 available after May 18. | Jul 4 |
| Swiss Chard | Mar 30 | May 11–May 11 | 143 | two-plantings: Plant May 11 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Arugula | — | Mar 30–Jun 22 | 199 | two-plantings: Plant Mar 30 and again by Aug 22; both mature before Oct 15. | Aug 22 |
| Brussel Sprouts | Mar 30 | Apr 27–May 11 | 171 | fits: 100 days to maturity, 171 available after Apr 27. | Jun 23 |
| Butternut Squash | May 11 | Jun 8–Jun 15 | 87 | head-start: Even planted out Jun 8, the outdoor season is about 13 days short; choose an early variety or grow under cover. | — |
| Eggplant | Apr 6 | Jun 8–Jun 15 | 80 | fits: 70 days to maturity, 80 available after Jun 8. | — |
| Okra | Apr 27 | Jun 1–Jun 8 | 101 | fits: 55 days to maturity, 101 available after Jun 1. | Jul 3 |
| Basil | Apr 20 | Jun 15–Jun 15 | 87 | fits: 60 days to maturity, 87 available after Jun 15. | Jun 28 |
| Cilantro | — | Apr 27–May 18 | 157 | two-plantings: Plant Apr 27 and again by Jul 29; both mature before Oct 1. | Jul 29 |
| Parsley | Mar 16 | Jun 1–Jun 8 | 122 | fits: 70 days to maturity, 122 available after Jun 1. | Jul 9 |
| Celery | Mar 16 | Jun 1–Jun 15 | 122 | fits: 120 days to maturity, 122 available after Jun 1. | — |
| Scallions | Mar 16 | Apr 27–May 11 | 171 | two-plantings: Plant Apr 27 and again by Aug 2; both mature before Oct 15. | Aug 2 |
| Turnip | — | Apr 27–May 11 | 171 | two-plantings: Plant Apr 27 and again by Aug 12; both mature before Oct 15. | Aug 12 |
| Kohlrabi | — | Apr 13–Apr 27 | 185 | two-plantings: Plant Apr 13 and again by Aug 7; both mature before Oct 15. | Aug 7 |
| Bok Choy | Apr 27 | May 18–May 25 | 136 | two-plantings: Plant May 18 and again by Aug 3; both mature before Oct 1. | Aug 3 |
| Collards | Mar 16 | Apr 27–May 11 | 171 | two-plantings: Plant Apr 27 and again by Aug 2; both mature before Oct 15. | Aug 2 |
| Cantaloupe | May 11 | Jun 8–Jun 15 | 80 | head-start: Even planted out Jun 8, the outdoor season is about 5 days short; choose an early variety or grow under cover. | — |
| Chives | Mar 2 | Jun 1–Jun 8 | 136 | fits: 90 days to maturity, 136 available after Jun 1. | — |
| Dill | — | Mar 30–Jun 22 | 185 | two-plantings: Plant Mar 30 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Oregano | Mar 16 | Jun 1–Jun 8 | 136 | fits: 80 days to maturity, 136 available after Jun 1. | — |
| Rosemary | Mar 2 | Jun 1–Jun 8 | 122 | fits: 80 days to maturity, 122 available after Jun 1. | — |
| Sage | Mar 30 | Jun 1–Jun 8 | 136 | fits: 75 days to maturity, 136 available after Jun 1. | — |
| Thyme | Mar 16 | Jun 1–Jun 8 | 136 | fits: 90 days to maturity, 136 available after Jun 1. | — |
| Calendula | Apr 13 | May 11–May 25 | 143 | two-plantings: Plant May 11 and again by Jul 29; both mature before Oct 1. | Jul 29 |
| Cosmos | Apr 27 | May 25–Jun 8 | 108 | fits: 60 days to maturity, 108 available after May 25. | Jun 28 |
| Lavender | Mar 2 | May 25–Jun 8 | 143 | fits: 90 days to maturity, 143 available after May 25. | — |
| Marigolds | Apr 13 | May 25–Jun 1 | 108 | fits: 50 days to maturity, 108 available after May 25. | Jul 8 |
| Melons | May 11 | Jun 8–Jun 15 | 80 | head-start: Even planted out Jun 8, the outdoor season is about 5 days short; choose an early variety or grow under cover. | — |
| Mint | — | May 25–Jun 8 | 143 | fits: 90 days to maturity, 143 available after May 25. | — |
| Nasturtiums | Apr 27 | May 25–Jun 1 | 108 | fits: 55 days to maturity, 108 available after May 25. | Jul 3 |
| Pole Beans | — | Jun 1–Jun 15 | 101 | fits: 65 days to maturity, 101 available after Jun 1. | Jun 23 |
| Spaghetti Squash | May 11 | Jun 8–Jun 15 | 87 | head-start: Even planted out Jun 8, the outdoor season is about 3 days short; choose an early variety or grow under cover. | — |
| Sunflowers | — | May 25–Jun 8 | 108 | fits: 70 days to maturity, 108 available after May 25. | Jun 18 |
| Tomatillos | Mar 30 | Jun 1–Jun 8 | 87 | fits: 75 days to maturity, 87 available after Jun 1. | — |
| Watermelon | May 11 | Jun 1–Jun 8 | 87 | fits: 80 days to maturity, 87 available after Jun 1. | — |
| Yellow Squash | May 11 | Jun 8–Jun 15 | 94 | fits: 55 days to maturity, 94 available after Jun 8. | Jul 3 |
| Zinnias | Apr 27 | May 25–Jun 8 | 108 | fits: 60 days to maturity, 108 available after May 25. | Jun 28 |
Month by month in Glenwood Springs
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost). |
| March | Start indoors: Chives (Mar 2), Lavender (Mar 2), Onion (Mar 2), Rosemary (Mar 2), Celery (Mar 16), Collards (Mar 16), +12 more. Direct sow from: Arugula (Mar 30), Beets (Mar 30), Dill (Mar 30), Peas (Mar 30), Radish (Mar 30), Spinach (Mar 30). |
| April | Start indoors: Eggplant (Apr 6), Calendula (Apr 13), Cauliflower (Apr 13), Marigolds (Apr 13), Pepper (Apr 13), Basil (Apr 20), +7 more. Direct sow from: Kohlrabi (Apr 13), Cilantro (Apr 27), Turnip (Apr 27). Transplant from: Broccoli (Apr 27), Brussel Sprouts (Apr 27), Cabbage (Apr 27), Collards (Apr 27), Kale (Apr 27), Lettuce (Apr 27), +2 more. Plant: Strawberry (Apr 20). |
| May | Start indoors: Cucumber (May 4), Butternut Squash (May 11), Cantaloupe (May 11), Melons (May 11), Pumpkin (May 11), Spaghetti Squash (May 11), +3 more. Direct sow from: Carrots (May 4), Potatoes (May 11), Sunflowers (May 25). Transplant from: Calendula (May 11), Swiss Chard (May 11), Bok Choy (May 18), Cauliflower (May 18), Cosmos (May 25), Lavender (May 25), +4 more. Last frost around May 25. |
| June | Direct sow from: Beans (Jun 1), Pole Beans (Jun 1). Transplant from: Celery (Jun 1), Chives (Jun 1), Corn (Jun 1), Okra (Jun 1), Oregano (Jun 1), Parsley (Jun 1), +17 more. Last sowing dates: Corn (Jun 6), Sunflowers (Jun 18), Brussel Sprouts (Jun 23), Pole Beans (Jun 23), Basil (Jun 28), Cosmos (Jun 28), +3 more. |
| July | Last sowing dates: Nasturtiums (Jul 3), Okra (Jul 3), Yellow Squash (Jul 3), Zucchini (Jul 3), Cauliflower (Jul 4), Beans (Jul 5), +10 more. |
| August | Last sowing dates: Collards (Aug 2), Scallions (Aug 2), Bok Choy (Aug 3), Lettuce (Aug 3), Kale (Aug 7), Kohlrabi (Aug 7), +4 more. |
| September | Direct sow from: Garlic (Sep 24). First frost around September 24. |
| October | Last sowing dates: Garlic (Oct 15). |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Glenwood Springs, CO (ZIP 81601)?
The median last spring frost date for Glenwood Springs, CO (ZIP code 81601) is around May 25. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before May 7; one in ten it runs past June 13.
What is the first fall frost date in Glenwood Springs, CO?
The median first fall frost date for Glenwood Springs, CO is around September 24. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 11 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Glenwood Springs, CO?
The frost-free growing season in Glenwood Springs is about 122 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Glenwood Springs (122 frost-free days, a moderate season), 35 of 56 planner crops fit outright, 15 get two plantings, 5 need an indoor start, 1 crop is perennial.
What USDA hardiness zone is Glenwood Springs, CO?
Glenwood Springs, CO is in USDA hardiness zone 6a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Glenwood Springs, CO?
Start tomatoes indoors Apr 20 and plant out Jun 8 in Glenwood Springs. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Glenwood Springs?
Two: plant Apr 27 and again by Aug 3; both mature before Oct 1.
When do I plant garlic in Glenwood Springs?
Sep 24 to Oct 15; it overwinters and is ready the following summer.
Can I grow Butternut Squash in Glenwood Springs?
Yes, with help. Even planted out Jun 8, the outdoor season is about 13 days short; choose an early variety or grow under cover.
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