CannaGLAP
Grow cannabis in Lafayette, CA
Growing cannabis in Lafayette: a damp late summer, then October air that suits the drying line
A Lafayette harvest is won or lost after the cut as much as before it. In 2024, October's outdoor air averaged 57 percent humidity, with afternoons near 78°F and nights near 53°F: close to the slow, steady conditions buds dry well in. August and September were damper.
So the question for a grower here is timing. Will your buds come down into that October air, or into a sticky late-summer 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.
Growing and drying in a Lafayette spare room
Summer heat is real but manageable. The Concord wastewater plant station, 7.2 miles away and 40 feet up, averages about 12 afternoons at 90°F in each of July and August, with highs near 88°F. Nights stay near 58 to 59°F. Run lamps from evening to morning so the hottest hours fall in the dark period, and let a fan pull that night air through the tent.
The harder weeks come next. Outdoor humidity jumped from 64 percent in July to 71 in August in 2024, just as photoperiod plants (the ones that flower as nights lengthen) began setting buds, and September stayed close behind. A tent in a garage or a room with open windows draws that air. A dehumidifier with a humidistat (a control that starts it when the air gets too moist) and airflow beneath the canopy keep colas, the dense top buds, from holding water.
October is where Lafayette pays you back. Branches hung in a cool, dark room that shares October's outdoor air can dry slowly enough to keep their smell, without the musty risk of damp air or the rushed dry of desert air. A closed room is not the outdoors, so check it with a hygrometer (a humidity gauge), and ease off the airflow if small stems snap within a few days.
Winter brings about 4 freezing nights a year, mostly in December and January, when lows sit near 41 to 42°F. A garage tent then wants the lamp through the coldest hours. January's 85 percent reading matters only in an unheated, damp space.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 58 | 63 | 68 | 72 | 78 | 85 | 88 | 88 | 86 | 78 | 67 | 59 |
| Avg low °F | 42 | 44 | 47 | 49 | 53 | 57 | 58 | 59 | 58 | 53 | 46 | 41 |
| Humidity % | 85 | 63 | 64 | 71 | 70 | 57 |
Highs and lows: NOAA 1991 to 2020 normals, Concord Wwtp station (7.2 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
The Lamorinda outdoor season
California permits up to 6 living plants per private residence, regardless of how many adults live there, provided they are locked up and not visible from any public place. Local governments can set rules for indoor grows and can forbid outdoor ones, and a landlord may prohibit growing on a rental, so confirm what applies at your address first.
Once you know outdoor plants are allowed, start seeds indoors March 4 to 18 and plant out from April 15. About 230 days separate that date from the early frost date of December 1, and only about one fall in ten brings frost by then. That gives a photoperiod plant time to finish in October's drier air instead of September's damp. Autoflowers bloom on age rather than night length; sown just days before they go out, they ripen in June and July, which were drier than August.
| Last spring frost | Jan 7 in a typical year, Feb 1 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 346 days |
| Nights stay 50°F or warmer | Apr 22 to Oct 29 |
| Start seeds or clones indoors | Mar 4 to Mar 18 |
| Move plants outdoors | Apr 15 or later |
A Lafayette grow, kept off the record
Lafayette is a place where you might run into a neighbor at the weekly farmers market and get asked how the garden is doing. A grow journal answers that question in far more detail than you ever would out loud.
Canna GLAP turns each grow record into code on your phone before it uploads. A breach of our servers would hand someone unreadable grow files and no key to open them. That shields the journal only: it cannot hide what drifts over a back fence. How you timed a clean October harvest stays your own.
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 Lafayette ask
When should I harvest outdoor cannabis in Lafayette?
Aim for October. In 2024 it had the driest air of the months measured, it brings only about 2 days at 90°F, and frost rarely comes before December.
Is Lafayette too hot for an indoor grow?
Not with the lamp on at night. The station sees about 47 hot afternoons a year, most from June through September, but nights cool into the high 50s, so night air carries much of the load.
Does Lafayette get frost?
A little. The last frost typically comes around January 7 and the first around December 19, so a garage tent needs extra warmth mainly in midwinter.
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