CannaGLAP
Grow cannabis in Upland, CA
Growing cannabis in Upland: choosing which season your buds ripen in
An Upland grow room has two seasons, and only one is easy. From December through February, the Ontario airport station, 4 miles away, averages highs near 67 to 68°F and lows near 44 to 46°F. From July through September it counts about 64 afternoons at 90°F or hotter.
Your plants do not care what month it is, only what the tent feels while they flower. So which of those two seasons are your buds ripening in?
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.
Timing an Upland indoor run
Line the flower weeks up with the cool half of the year. A run flipped to 12 hours of light in late fall ripens through December and January, when a garage tent near Foothill Boulevard stays cool with little effort. Run the lamp overnight then, so its heat covers the 44 to 46°F lows. Flowering in August, the same tent meets outdoor highs near 95°F before its lamp adds a degree.
If you do flower through summer, move the lamp to nights from June through September. August lows average about 65°F, some 30 degrees under the afternoon, so an intake fan on a timer pulls cool air across the canopy while the light runs. A closed garage usually still needs an air conditioner in July and August; heat-stressed plants can set loose, airy buds.
Dry air follows the heat. In 2024, humidity slid from 63 percent in June to 52 in August, rose to 56 in September and dropped to 47 in October, the lowest of the six months measured, January included. Seedlings and fresh clones want more moisture, so give them a dome or a small humidifier for two weeks. Late flower gains from the dry air, since bud rot needs damp, but cut branches dry quickly: hang them in a closed room.
A winter run has small chores of its own. The station logs about 2 freezing nights a year, mostly in December and January, so a heat mat under young plants is cheap insurance in a garage. January's 69 percent outdoor reading fades inside a heated home; only an unheated, damp garage would need a dehumidifier then.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 68 | 68 | 72 | 76 | 80 | 86 | 94 | 95 | 91 | 83 | 75 | 67 |
| Avg low °F | 45 | 46 | 49 | 51 | 56 | 60 | 65 | 65 | 64 | 57 | 49 | 44 |
| Humidity % | 69 | 63 | 55 | 52 | 56 | 47 |
Highs and lows: NOAA 1991 to 2020 normals, Ontario International Airport station (4 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
Outdoors at the western edge of the Inland Empire
State law sets the cap at 6 living plants for each private residence, no matter how many adults share it, kept in a secured, locked spot that is not visible from public places. Local rules stack on top: a city or county may set reasonable terms for an indoor grow but not forbid one, and may forbid outdoor plants outright. Look up Upland's rules before planting a yard.
Where it is allowed, begin seeds inside from March 4 through 18 and plant out from April 15; frost is rarely a factor, and nights average 50°F from April 1. Summer is the limit: an outdoor plant spends July and August under highs near 94 to 95°F. Afternoon shade and deep morning watering help it through, and its buds then ripen into a dry October.
| Frost | Rare: about 1.7 freezing nights a year |
|---|---|
| Nights stay 50°F or warmer | Apr 1 to Nov 12 |
| Start seeds or clones indoors | Mar 4 to Mar 18 |
| Move plants outdoors | Apr 15 or later |
What your passphrase keeps closed
A grow can be private even from the people closest to it: a landlord who checks the garage, a roommate, a visiting relative. A locked, hidden space keeps the plants out of view. The hum of a fan at midnight and the smell in September are yours to manage; no app can encrypt those.
What Canna GLAP locks is the journal. Your grow records are encrypted on your phone before upload, so if someone broke into our servers, the haul would be grow entries nobody can read, with no key. The winter schedule behind your best run stays yours.
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 Upland ask
When is the best time to flower cannabis indoors in Upland?
Late fall through winter, when the tent stays cool with little effort: December through February average highs near 67 to 68°F. Flowering from July through September means about 64 days at 90°F and an air conditioner for the garage.
Does Upland get frost?
Rarely. The Ontario airport station logs about 2 freezing nights a year, mostly in December and January, and the average night stays at 45°F or warmer from January 23 to December 8.
Is bud rot a risk in Upland?
Low, for the most part. Humidity fell to 47 percent in October 2024 and 52 in August; the bigger risk is buds drying too fast after the cut.
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