CannaGLAP
Grow cannabis in Pueblo, CO
Growing cannabis in Pueblo: a September that brings 90-degree afternoons and the first frost
Pueblo summers run hot. At the weather service station about 5 miles away, which sits at 4,653 feet, July averages 93°F, and about 23 of its days hit 90°F. Then September asks for two things at once. It still averages about 11 days at 90°F, and in a cold year it also delivers the first frost, by September 28.
A plant in late flower will not be ready for both by accident. Which one is your run planned around?
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.
Indoors in Pueblo: long heat, then a hard freeze
The heat runs deep. About 17 days reach 90°F in June, 23 in July, 19 in August and 11 in September, roughly 70 in four months. A tent in a garage near Mesa Junction or a back room off Union Avenue climbs well past the room on those afternoons. Put the light period overnight from June through September.
Nights work in your favor. July lows average about 61°F, some 32 degrees under the afternoon, so the dark period cools on its own and sheds the lamp's heat fast. Flowering plants welcome that drop; seedlings and clones should be kept warmer than the room once the lights go out.
The air stays dry. June and July average 38 percent humidity, August 42 and September 37, which keeps bud rot pressure low in a flower room. Young plants feel the other side of it, so a dome or a humidifier close by helps them root.
Winter is where Pueblo bites. December nights average about 15°F and January's about 16°F, almost every night of both months freezes, and the station counts about 152 freezing nights a year. A garage tent needs a heater on a thermostat after dark, pots off the concrete, and lights that run through the small hours.
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 | 48 | 51 | 60 | 68 | 77 | 88 | 93 | 90 | 83 | 70 | 57 | 47 |
| Avg low °F | 16 | 18 | 27 | 36 | 46 | 55 | 61 | 60 | 50 | 36 | 23 | 15 |
| Humidity % | 56 | 38 | 38 | 42 | 37 | 40 |
Highs and lows: NOAA 1991 to 2020 normals, WFO Pueblo station (5.1 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
Outdoors in Pueblo County: residents, locks and a September deadline
Colorado home growing is for residents: 6 plants each, with 3 or fewer flowering at a time, and 12 per residential property unless local law allows more. Keep them enclosed and locked, out of open view; if someone under 21 shares the home, the plants go in their own locked space. Local rules may be stricter, so read Pueblo's before you build.
In a qualifying greenhouse or enclosure, start seeds April 2 to 16 and move plants out May 14 or later. The last frost typically comes around April 30, though one spring in ten it is still around on May 12. Frost usually returns around October 9 and as early as September 28, which gives about 137 days. That is where September's double bind bites: a photoperiod still flowering through a 90°F week can meet frost before the month is out. Autoflowers or fast strains bred to finish by mid September avoid it; keep a frost cloth ready by late September.
| Last spring frost | Apr 30 in a typical year, May 12 to be safe (later only 1 year in 10) |
|---|---|
| First fall frost | Oct 9 typical, as early as Sep 28 (1 year in 10) |
| Frost-free season | about 162 days |
| Nights stay 50°F or warmer | May 30 to Sep 15 |
| Start seeds or clones indoors | Apr 2 to Apr 16 |
| Move plants outdoors | May 14 or later |
| Season note | Frost can arrive before mid October here: long flowering plants may not finish outdoors |
A growing town, and a log that stays put
Pueblo takes local growing seriously. The chile is a point of pride, and the Chile and Frijoles Festival and the Saturday market at Mineral Palace Park draw people who love to compare what they grow. Talk peppers all morning. The cannabis log is a different conversation, and one you can keep to yourself.
Canna GLAP encrypts the grow on the phone before upload. Someone who cracked our servers would walk away with ciphered grow records and no key. What you learned about growing between Pueblo's extremes stays your edge.
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 Pueblo ask
What date can Pueblo cannabis plants go outside?
May 14 or later, after starting seeds April 2 to 16. You then have about 137 days before an early frost, which can arrive by September 28.
Is Pueblo too hot to grow cannabis in summer?
Not too hot, but it takes planning: about 23 July days reach 90°F. Run tent lights overnight; July nights near 61°F help plants recover.
Can I grow cannabis in Pueblo if someone under 21 lives with me?
Colorado requires a separate locked space for the plants in that case. You must also be a Colorado resident.
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