CannaGLAP
Grow cannabis in Riverside, CA
Growing cannabis in Riverside: the heat builds into August and stays through flower
Riverside's heat does not peak in July and fade. It keeps building. At the Citrus Experiment station, 1.2 miles away, August averages a 97°F high and about 27 of its days reach 90°F. September still brings about 20 such days, and October about 9.
A plant set out in spring does its flowering inside that stretch. So when your buds are ripening, how hot is the canopy, really?
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.
Running a Riverside tent through the long heat
The year's numbers explain the job. About 103 days reach 90°F, and frost is close to a non-issue at about 2 freezing nights a year. A garage tent in a Riverside ranch home can run far hotter than the thermostat inside the house reads, and heat in late flower costs aroma and loosens buds. Put the tent in an air-conditioned room from June through October, not in the garage.
Night is your best cooling. August lows average about 64°F, some 33 degrees under the afternoon high, so lights that run from evening to morning let the tent sit dark through the worst of the day. Pull intake air from the coolest side of the house.
Humidity is middling, not desert dry: about 50 percent in July, 48 in August and 45 in October. Mold pressure in flower is modest, so put your effort into heat. Seedlings still like a dome for their first week or two.
The easy months are the other half of the year. December and January average highs near 69°F to 70°F and lows near 43°F to 44°F, so a tent run from November through May needs little heating or cooling. If you plan one big indoor harvest a year, those months are the cheap ones to run it in.
| 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 % | 71 | 59 | 50 | 48 | 53 | 45 |
Highs and lows: NOAA 1991 to 2020 normals, Riverside Citrus Exp station (1.2 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
Outdoors in Riverside County
California allows 6 living plants per private residence, however many adults live there, in a locked space that cannot be seen from a public place. Cities and counties can add rules and may ban outdoor grows, so check what applies to your address before you plant outside.
Frost is rarely the issue here; heat is. Start seeds from March 4 to 18 and plant out on April 15, when nights have averaged above 45°F since mid February. Mulch the soil, water deeply, and give plants afternoon shade from July through September. Nights stay 50°F or warmer on average until about November 5, so an October finish faces heat, 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 |
Six plants a residence, one private log
Six plants per residence means everyone under one roof shares the same count, whether that roof is a Canyon Crest condo or a house off Magnolia Avenue. What you learn from them, a 97°F August at a time, is worth keeping close.
Canna GLAP encrypts the grow records themselves on the phone before upload. If attackers broke into our servers, a Riverside grow would reach them as unreadable records with no key to open them. Talk shop on an ArtsWalk First Thursday if you like; what you tell people is your call.
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 Riverside ask
When should I plant cannabis outside in Riverside?
From April 15, with seeds started indoors March 4 to 18. Freezing nights are rare, about 2 a year, so the planting date is about warmth, not frost.
Can I grow cannabis outdoors in Riverside?
California allows it in a locked space not visible from a public place, up to 6 plants per residence, but cities and counties can regulate outdoor grows or ban them. Check the rules for your address first.
What is the best time of year to grow indoors in Riverside?
November through May. Highs in December and January average near 69°F to 70°F, so a tent needs little climate control, while August averages a 97°F high.
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