Colorado planting calendar

When to plant potatoes in Colorado — sow, transplant & harvest dates

Colorado is mostly USDA zone 5b (range 3b-7a). Dates below are derived from potatoes's frost tolerance and Colorado's frost window — not generic national averages.

Potatoes planting timetable for Colorado

Stage	When in Colorado	Anchor
Direct-sow outside	late April (April 24)	21 days before the last frost (mid-May)
First harvest (estimate)	mid-July (July 18)	~85 days from direct sow

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Colorado's climate shifts the potatoes dates

Colorado's last spring frost averages mid-May and first fall frost late September, which sets the whole planting clock. Colorado gardening is shaped by altitude, intense sun, low humidity, and big day-night temperature swings. Frost can come in any month at high elevation. Sow early — potatoes bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Potatoes are planted as certified seed potatoes (not supermarket tubers) 2-4 weeks before the last spring frost, once soil temperature reaches at least 7 °C; they tolerate light frost in the ground but emerging foliage is killed below -2 °C, so hill soil over any shoots that break through during a late freeze. In zones 9-11 potatoes are a winter or early-spring crop, planted in late January-February to mature before summer heat forces them dormant. Days-to-harvest ranges from 70 days for early/new-potato types to 110-120 days for maincrop storage varieties.

Frost-risk note

Don't plant before mid-May — a hard freeze can still set young plants back. In the high Rockies and mountain valleys (zone 3b-4b) the safe date runs a week or two later.

Regional variation within Colorado

the high Rockies and mountain valleys (zone 3b-4b) runs roughly 1-2 weeks behind the state average; the western slope around Grand Junction (zone 7a) can plant 1-2 weeks earlier.

Denver — USDA zone 6a
Colorado Springs — USDA zone 6a
Boulder — USDA zone 6a
Grand Junction — USDA zone 7a
Fort Collins — USDA zone 5b

What else to plant in Colorado around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun — 6-8 hours direct.
Soil temperature for germination: Soil 7-18 °C (45-65 °F) at planting.
Spacing: 10-15 inches (25-38 cm) between plants.
Days to harvest: ~85 days from planting out.

Frequently asked questions

When is the best time to plant potatoes in Colorado?

In Colorado (mostly USDA zone 5b), direct-sow potatoes late April (before the last frost, mid-May), and harvest from mid-July. Potatoes are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

What USDA zone is Colorado?

Most of Colorado sits in USDA hardiness zone 5b, with the state spanning roughly 3b-7a from the high Rockies and mountain valleys (zone 3b-4b) to the western slope around Grand Junction (zone 7a). The last spring frost averages mid-May and the first fall frost late September.

Can you grow potatoes in Colorado?

Yes. Colorado's dominant zone 5b supports potatoes — the key is timing. Potatoes are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

Does the planting date change across Colorado?

the high Rockies and mountain valleys (zone 3b-4b) runs roughly 1-2 weeks behind the state average; the western slope around Grand Junction (zone 7a) can plant 1-2 weeks earlier.

What else can I plant in Colorado around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.