CannaGLAP
Grow cannabis in Colorado Springs, CO
Growing cannabis in Colorado Springs: the cold nights decide your harvest
It is tempting to watch the afternoon high in Colorado Springs, but your plants care far more about the night. The airport station sits at 6,181 feet, and the city averages about 160 nights a year at or below freezing.
That is close to half the calendar. So here is the better question: what is the coldest hour your plants actually live through, and have you ever measured it?
Adults 21 and over: yes (residents). Plant limit: 6 per resident, 3 or fewer flowering; 12 per residential property unless local law allows more.
Enclosed, locked area not openly visible; separate locked space if anyone under 21 lives there; local rules can be stricter. Source: Colorado home grow laws; 12 plant cap: HB 17-1220. Local rules (landlords, HOAs, city codes) can add more; this is a summary, not legal advice.
Building a Colorado Springs grow around the cold
December and January lows average about 19°F. A garage or an unheated basement corner in El Paso County can fall well below what cannabis roots tolerate once the lights shut off, and cold roots stop feeding long before the leaves show it. Insulate the floor under the tent, put young plants on a heat mat, and schedule the lights to cover the small hours of the morning, which is when the house is coldest.
Even July plays this game. Days average about 87°F, with roughly 11 days at or above 90°F, yet nights drop to around 58°F. That swing of nearly 30 degrees is useful in late flower, where a cooler dark period can deepen color, but a seedling tent left to follow the room overnight will crawl. A small heater on a thermostat keeps dark-period temperatures steady.
Humidity runs moderate, about 41 to 50 percent through summer and 41 percent in September and October. That keeps bud rot pressure low, though the thin air at this altitude still dries pots quickly; check them every day rather than on a fixed schedule.
Heater safety: use one with tip-over and overheat shutoff, plug it straight into a wall outlet (not an extension cord or power strip), and keep it a few feet from tent fabric and plants.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 45 | 47 | 55 | 61 | 71 | 82 | 87 | 84 | 77 | 65 | 53 | 45 |
| Avg low °F | 19 | 20 | 27 | 34 | 44 | 53 | 58 | 57 | 49 | 37 | 26 | 19 |
| Humidity % | 64 | 43 | 41 | 50 | 39 | 42 |
Highs and lows: NOAA 1991 to 2020 normals, Colorado Springs Muni Airport station (7.4 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
A short season for Colorado residents only
Colorado home grow is for state residents, and plants must be in an enclosed, locked area that is not openly visible, with a separate locked space if anyone under 21 lives in the home. Local rules can be stricter, so check yours before you build. A locked greenhouse is the setup that makes most sense near Old Colorado City or out toward Manitou Springs.
The window is narrow. Nights only average 45°F from May 20 to September 25, and one year in ten the first fall frost has come by September 26. Set plants out on May 20 or later and count on roughly 129 workable days. Autoflowers and fast-finishing photoperiods are the realistic choice; a plant that wants to flower into mid October will meet frost first.
| Last spring frost | May 3 in a typical year, May 15 to be safe (later only 1 year in 10) |
|---|---|
| First fall frost | Oct 8 typical, as early as Sep 26 (1 year in 10) |
| Frost-free season | about 158 days |
| Nights stay 50°F or warmer | Jun 6 to Sep 11 |
| Start seeds or clones indoors | Apr 8 to Apr 22 |
| Move plants outdoors | May 20 or later |
| Season note | Frost can arrive before mid October here: long flowering plants may not finish outdoors |
What your grow log says about you
At this altitude, growers learn by trial, and the trials that worked are worth writing down. Those lessons are why a second season goes better than the first, and they are exactly what another El Paso County grower would love to skip ahead to. In most apps they sit where the company can read them.
Canna GLAP encrypts the whole grow on your phone before anything uploads. A break-in at our servers would turn up your grow records in scrambled form, with no key in reach. We cannot read the lessons either.
What is encrypted: your plants, notes, photos, feed logs and harvests. What is not: account details (such as your email, name and plan), a grow name or town if you type one, your team, and your sensors' names. The full list: what a hacker would get.
Questions growers in Colorado Springs ask
When can I put cannabis outside in Colorado Springs?
May 20 or later, once nights average 45°F. Frost has cleared by May 15 in 90 percent of years, and you can root clones or sprout seeds indoors from April 8 to April 22.
Can non-residents grow cannabis in Colorado Springs?
No. Colorado home grow is for residents, and plants must be in an enclosed, locked area out of open view. Local rules can be stricter, so check El Paso County and city requirements too.
Will a photoperiod strain finish outdoors in Colorado Springs?
Only a fast one. In an early year (1 in 10), frost can arrive by September 26, leaving about 129 outdoor days, so autoflowers or early-finishing strains are the safer bet.
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