CannaGLAP
Grow cannabis in Fontana, CA
Growing cannabis in Fontana: an October harvest in 37 percent air
Fontana's air gets drier as the year ripens. Humidity averaged 54 percent in June, 40 in August and 37 in October, the driest of the months measured. Soft air while a plant grows leaves; parched air as its buds finish and hang to dry.
Heat rides along with it. The Riverside Citrus Experiment station, 9.6 miles away, averages a 97°F August high. So when you cut a plant in October, what waits for it: a slow, even dry, or a rushed one?
Adults 21 and over: yes. Plant limit: 6 living plants per private residence, however many adults live there.
Locked space, not visible from a public place; cities and counties can set reasonable rules for indoor grows (but cannot ban them) and may ban outdoor grows; a landlord may prohibit growing on a rental. Source: Department of Cannabis Control; conditions: Prop 64 text as passed in 2016 (H&S Code 11362.2 and 11362.45). Local rules (landlords, HOAs, city codes) can add more; this is a summary, not legal advice.
Fontana indoors: the heat first, then the dry
August is the hottest month at that station, when about 27 days reach 90°F; July adds about 23 such days and September about 20. A garage tent stacks lamp heat on top of all that. Put the grow where the house air conditioning reaches, or give an insulated garage its own window unit, and draw intake air from the coolest room instead of from outside.
Nights help, within limits. August lows average about 64°F and October lows about 55°F, so a lamp schedule that runs from evening to early morning keeps the lights' heat away from the 97°F afternoons. In winter, lows near 43°F to 44°F in December and January can chill a garage tent overnight; a thermostat-run space heater handles it.
Young plants get the kindest air of the months measured: June's 54 percent suits clones and seedlings. Later the picture changes: September averaged 46 percent and October 37, so mold pressure in late flower stays low, and the budget can go to cooling rather than a dehumidifier.
The harvest is where the dry air costs you. Buds hung in an open garage in October can lose moisture too fast, and a rushed dry tends to take the smell with it. Dry in a closed room or a spare tent with a hygrometer, aiming near 60 percent humidity and 60°F to 65°F if your space allows, fans pointed away from the branches.
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 | 70 | 70 | 72 | 75 | 80 | 87 | 94 | 97 | 93 | 82 | 76 | 69 |
| Avg low °F | 44 | 45 | 47 | 50 | 55 | 58 | 63 | 64 | 61 | 55 | 47 | 43 |
| Humidity % | 65 | 54 | 41 | 40 | 46 | 37 |
Highs and lows: NOAA 1991 to 2020 normals, Riverside Citrus Exp station (9.6 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
Outdoors in San Bernardino County
California's count is 6 living plants for a private residence, no matter how many adults share it, kept in a locked space hidden from every public place. A city or county can add its own regulations and may ban outdoor grows outright, so check what applies to your Fontana address before anything goes in the ground.
Frost hardly figures, at about 2 freezing nights a year. Sow seeds indoors between March 4 and 18, and move plants outside on April 15, the day before nights begin averaging 50°F or warmer (April 16 through November 5). Then give plants shade cloth on the hottest afternoons, mulch and deep, early-morning watering through August and September. An October finish faces warm, dry days near 82°F, not cold.
| Frost | Rare: about 1.7 freezing nights a year |
|---|---|
| Nights stay 50°F or warmer | Apr 16 to Nov 5 |
| Start seeds or clones indoors | Mar 4 to Mar 18 |
| Move plants outdoors | Apr 15 or later |
Your Fontana numbers, kept to yourself
Talk gardens at the Spring Street Night Market or the farmers' market at Fontana Park all you like. What you write down is separate, and it holds the fixes that only a hot August and a dry October could teach.
Canna GLAP encrypts those grow records on your phone before upload. Someone who forced a way into our servers would find them scrambled and keyless. And since 6 plants is the count for everyone under one roof, the whole residence shares the limit without sharing a log.
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 Fontana ask
When should I plant cannabis outside in Fontana?
On April 15, with seeds started indoors March 4 to 18. Frost is rare, about 2 nights a year, so the date is about warm nights, which average 50°F or warmer from April 16 to November 5.
How do I keep a grow tent cool in a Fontana summer?
Put it where the house air conditioning reaches, or give an insulated garage its own window unit, and run the lights from evening to morning. August averages a 97°F high, with about 27 days reaching 90°F, but its nights fall to about 64°F.
Why do my buds dry so fast in Fontana?
October air averaged 37 percent humidity, the driest of the months measured. Dry in a closed space with a hygrometer and let it take a week or more.
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