CannaGLAP
Grow cannabis in Greenwich, CT
Growing cannabis in Greenwich: a run that starts in damp summer air and finishes under the furnace
A Greenwich grow started in July is living in a different house by the time it finishes. At the Westchester County airport station, about 5 miles away across the state line, July and August both average 76 percent humidity. Then the cold comes in a rush: about 1 freezing night in October, about 10 in November, about 22 in December. Somewhere in that slide, the heat goes on.
Most grow plans set the dehumidifier once and leave it. Has yours ever been asked to do the opposite job halfway through a run?
Adults 21 and over: yes. Plant limit: 3 mature + 3 immature per adult; 12 per household.
Indoors at your primary residence, where under 21s cannot get at the plants; not visible from the street. Source: CT cannabis portal. Local rules (landlords, HOAs, city codes) can add more; this is a summary, not legal advice.
One Greenwich grow room, two seasons of air
Summer near Long Island Sound is warm and wet rather than hot. July highs average about 83°F, with about 5 afternoons reaching 90°F, and nights hold near 65°F. A tent in a guest room or a finished basement keeps that moisture, and it climbs once the lamps switch off. Size the dehumidifier for the dark period and leave a hand's width between colas.
September still averages 72 percent, the weeks when a plant flipped in August is stacking weight. Strip the lower growth that never sees the light and aim a small fan beneath the canopy. October eases to about 64 percent, the lowest of the months measured here, so a run that finishes then has the easier air.
November changes the job. Winter air outside still reads high (January averages 72 percent), but air that cold carries very little water, and once a furnace warms it a living space runs dry. A run still flowering when the heat comes on can swing from too wet to too dry, so keep a hygrometer at canopy height and let it decide which machine runs. An unheated, damp basement is the exception, and there the dehumidifier stays on.
Cold sets the last limit. January lows average about 22°F, with about 26 freezing nights that month and about 105 in a year. A room over the garage cools hard after midnight, so run the lights through the small hours, lift pots off cold floors, and put young plants on a heat mat.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 37 | 40 | 48 | 59 | 69 | 78 | 83 | 81 | 74 | 63 | 52 | 42 |
| Avg low °F | 22 | 24 | 31 | 40 | 50 | 59 | 65 | 64 | 57 | 46 | 36 | 28 |
| Humidity % | 72 | 69 | 76 | 76 | 72 | 64 |
Highs and lows: NOAA 1991 to 2020 normals, Westchester Co Airport station (5 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
The calendar outside a Greenwich grow room
Connecticut keeps home cannabis indoors, at your primary residence, out of reach of anyone under 21 and not visible from the street. A garden, porch or deck does not qualify. The outdoor calendar still tells an indoor grower when the shift is coming: nights average 45°F or warmer only until about October 17, and the first frost typically lands around October 31, by October 15 in a cold year. Expect dry furnace air to arrive in those weeks.
| Last spring frost | Apr 12 in a typical year, Apr 27 to be safe (later only 1 year in 10) |
|---|---|
| First fall frost | Oct 31 typical, as early as Oct 15 (1 year in 10) |
| Frost-free season | about 200 days |
| Nights stay 50°F or warmer | May 16 to Oct 3 |
| Growing outdoors | Not allowed: Connecticut law keeps plants indoors. These dates are the season outside your grow room. |
Locked plants, and a log that matches
Plenty of Greenwich homes have people passing through: a contractor on a renovation, a house sitter for a long weekend, guests after dinner on Greenwich Avenue. The log deserves a lock of its own, because it holds what each season taught you.
Canna GLAP encrypts the grow itself on your phone before any of it reaches our servers. Someone who broke into those servers would leave with grow records in scrambled form and nothing that unscrambles them. On the Gold Coast, the numbers you worked out are yours to share or keep.
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 Greenwich ask
Can I grow cannabis on my Greenwich patio or in the yard?
No. Connecticut allows home growing only indoors at your primary residence, where no one under 21 can get at the plants and nothing shows from the street. Each adult may keep 3 mature plants and 3 immature ones, with a 12 plant cap for the household.
When does a Greenwich flower room need a dehumidifier?
From summer into early fall. July and August average 76 percent humidity and September 72, while October eases to about 64, so a run that finishes in October has the easier air.
Why are my Greenwich clones drying out in winter?
Heated air. The January reading outdoors is about 72 percent, but cold air carries little moisture, and a furnace-warmed room runs dry. A dome or a small humidifier fixes it; only an unheated, damp basement stays wet.
Growing near Greenwich
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