CannaGLAP
Grow cannabis in Highland, CA
Growing cannabis in Highland: a hot flowering season and a harvest in very dry air
Highland's harvest weather is dry. Humidity averaged 35 percent in October 2024, the lowest of the months measured, and October afternoons still average about 83°F. A plant cut then gives up its water fast, sometimes faster than a good dry allows.
At that humidity, bud rot is a small worry. A rushed dry is the bigger one. So where will your harvest hang for its first week?
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.
Highland indoors: heat in flower, dry air at the cut
The heat arrives first. The Redlands station, 6.4 miles away at 1,410 feet, averages about 24 afternoons at 90°F in July, 26 in August and 21 in September, and a tent in a closed Highland garage can run hotter than the air outside it. Run the light from evening to morning, when outside air falls toward lows of about 63°F in July and August and the exhaust has cooler air to pull.
Dry air works on both ends of a run. Outdoor humidity fell from 52 percent in June to 39 in July and 37 in August. Seedlings and fresh clones lose water faster than new roots can replace it in air like that, so give them a dome or a small humidifier for their first two weeks.
The cut is where the dry air asks the most. Buds dry best slowly, over a week or more, in air near 60°F and 60 percent humidity. Hung in an October garage at 35 percent, they can turn brittle in a few days, and a fast dry tends to cost smell. Dry in a small closed room or tent with a humidifier on low, and aim the fan around the branches, rather than straight at them.
Winter is real but short. December lows average about 40°F and January's about 41, so a garage tent wants the lamp on through the coldest hours and a mat under young roots. January's 63 percent outdoor reading fades inside a heated house.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 67 | 67 | 71 | 76 | 80 | 89 | 95 | 96 | 92 | 83 | 75 | 67 |
| Avg low °F | 41 | 42 | 45 | 48 | 52 | 56 | 63 | 63 | 60 | 53 | 45 | 40 |
| Humidity % | 63 | 52 | 39 | 37 | 45 | 35 |
Highs and lows: NOAA 1991 to 2020 normals, Redlands station (6.4 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
A Highland outdoor season
Highland growers fall under California's cap: 6 living plants per private residence, however many adults live there, kept locked away and out of sight from any public place. Read Highland's rules too, since local governments can set reasonable rules for indoor grows (but cannot ban them) and may ban outdoor ones.
Should your outdoor grow be allowed, sow seeds inside during March 4 to 18 and transplant on or after April 15. Highland does get frost, about 3 freezing nights a year at the station, but the first one typically waits until December 19 and arrives by December 1 one fall in ten, about 230 days after planting. Heat is the limit instead: a plant in flower in September faces about 21 afternoons at 90°F, so shade on the hottest afternoons and deep, regular watering matter more than the calendar. The dry October air that keeps mold down also dries pots fast.
| Last spring frost | Jan 27 in a typical year, Feb 28 to be safe (later only 1 year in 10) |
|---|---|
| First fall frost | Dec 19 typical, as early as Dec 1 (1 year in 10) |
| Frost-free season | about 329 days |
| Nights stay 50°F or warmer | Apr 30 to Oct 27 |
| Start seeds or clones indoors | Mar 4 to Mar 18 |
| Move plants outdoors | Apr 15 or later |
Highland notes that stay with you
Run into another grower at the Downtown Redlands Morning Market, in nearby Redlands, and the talk can turn to your last harvest in a hurry. What you say out loud is up to you. What you wrote down should be too.
Your Canna GLAP journal is encrypted on the phone itself, before any of it uploads. A breach of our servers would hand an intruder grow records they could not read, with no key among them. It does not hide a fan running in the garage or the smell of a drying room; it keeps your notes 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 Highland ask
Is bud rot a problem in Highland?
It is a smaller worry than heat and fast drying. Humidity averaged 45 percent in September 2024 and 35 in October, low for mold, though a dense cola can still trap moisture at its center.
How do I dry cannabis in Highland's dry air?
Slowly, in a closed space. Hung in 35 percent October air, buds can dry in a few days; a small room or tent with a humidifier on low, aiming near 60 percent, stretches it to a week or more.
Does Highland get frost?
A little. The Redlands station averages about 3 freezing nights a year, with December and January holding most of them, and the first fall frost typically arrives around December 19, well after an outdoor harvest.
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