Colorado · zones 5a–7a
When to plant potatoes in Colorado.
Sow between Apr 1 to May 4 in a typical year, keyed to Colorado's median last frost around May 9. A second, fall sowing fits Jun 11 to Jun 24. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Potatoes dates for a typical Colorado season.
Direct sow
Apr 1 to May 4
Keyed to the ~May 9 last frost. Sow 4" deep, 12" apart.
Fall round
Jun 11 to Jun 24
Counted back from the ~Sep 29 first frost.
Harvest
~90 days later
~3 lb per plant over ~1 weeks.
Colorado spans more than one climate: Zone 6 is the most common zone, but the state runs 5a to 7a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
Colorado growing notes
The beetle carries your state's name. Here is how San Luis Valley growers beat it anyway.
A pedigree from the valley next door
Colorado is a serious potato state, and the San Luis Valley, a high desert basin averaging around 7,500 feet, grows the bulk of it. The valley's volcanic, sandy loam soil drains fast, and its nights regularly drop into the 40s even in July, conditions that hold aphid populations down enough to make the valley one of the country's certified seed potato regions. A home gardener anywhere in the state benefits from starting with certified seed rather than grocery-store potatoes, which can carry the very viruses the valley's isolation is built to avoid.
Sangre, a red-skinned variety released by Colorado State University's own breeding program, and Yukon Gold both perform well at altitude, sizing up in the roughly 90 days a home-garden potato typically needs. Plant seed pieces cut side down with 2 healthy eyes each, and hill soil up around the stems twice as they grow, keeping developing tubers covered; a tuber that pokes through and greens under this state's intense high-altitude sun is no longer edible.
The beetle named after this exact ground
The Colorado potato beetle carries this state's name because of an 1860s report filed out of Colorado Territory, though the insect's actual lineage traces back to central Mexico and the southern Plains, a detail most gardeners never hear. What is well documented is the 1859 host shift: the beetle switched from wild plants onto cultivated potatoes on the Nebraska plains that year, then marched east across the country over the following decades, and it remains the single biggest threat to a Colorado potato patch today. Adults and the humpbacked orange larvae both strip leaves fast enough to cut yield in half if left unchecked.
Check the undersides of leaves weekly for the beetle's tidy clusters of yellow-orange eggs, usually 20 to 30 per cluster, and crush them on sight; a single missed cluster becomes two dozen leaf-eating larvae within 2 weeks. Hand-picking adults into a bucket of soapy water each morning, while the cool air still has them sluggish, controls a home-size patch without a single spray in most seasons.
Daily water math for a thin, dry atmosphere
Colorado's low humidity and intense sun pull moisture out of soil faster than the rainfall totals suggest a garden needs, and potatoes are unforgiving about that gap: uneven watering during tuber set produces hollow centers and knobby, misshapen tubers. Budget roughly 1.5 to 2 inches of water a week during the 6 weeks after hilling, split across 2 or 3 waterings rather than one soak, since sandy or clay Colorado ground either drains too fast or sheds a downpour off the surface in a single storm.
A simple test beats guessing: push a finger 3 inches into the hill 2 days after watering, and if it comes out dry, tighten the schedule before the next round. Taper watering back over the final 2 weeks before digging so skins can set; tubers lifted from ground that is still saturated bruise and store far worse than ones pulled from soil that has been allowed to firm up.
In Colorado: watch for
The pests that find potatoes here.
The short season here, about 143 frost-free days, keeps potato in front of colorado potato beetle only briefly. One early row cover usually carries a planting through the worst of it.
Striped beetles and orange grubs eating the leaves.
Organic fix: Handpick adults, crush the orange egg clusters, dust with diatomaceous earth.
Dark greasy blotches after cool, wet spells.
Organic fix: Pull infected plants fast, keep leaves dry, use neem as a preventive.
Common scab
Rough, corky patches on the skin, raised on some tubers and sunk into pits on others.
Organic fix: Keep the bed evenly moist through the weeks right after tubers set, rotate away from potatoes, and pick a scab-resistant variety next time.
Your season math: Colorado gives potatoes about 143 frost-free days, and it needs roughly 90 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting potatoes in Colorado: questions
When should I plant potatoes in Colorado?+
In a typical Colorado year, sow potatoes between Apr 1 to May 4, keyed to the state's median last frost around May 9. There's also a fall window: Jun 11 to Jun 24. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is Colorado?+
Colorado spans zones 5a–7a, mostly zone 6. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many potatoes plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.