CannaGLAP
Grow cannabis in Lake Oswego, OR
Growing cannabis in Lake Oswego: ten points of humidity between September and October
In Lake Oswego, the month a plant finishes can matter more than the strain. Humidity averages 69 percent in September and 79 percent in October, a ten-point jump in one month, while frost holds off until October 30 even in an early fall.
A plant that ripens in late September and one that ripens in late October live in two different climates. Which of those two months is your next harvest planned for?
Adults 21 and over: yes. Plant limit: 4 per household, however many adults live there.
Four adults in one home still means 4 plants in total. Source: OLCC FAQ. Local rules (landlords, HOAs, city codes) can add more; this is a summary, not legal advice.
Timing a Lake Oswego indoor grow
Indoors you pick the month, and the outdoor numbers show which ones help. July is the driest month measured, at 55 percent, with August at 61. A flower run timed to finish in August or early September pulls in the easiest air on the station record from June to October, and a small dehumidifier only has to trim the top off.
Summer heat is brief. The Oregon City station, 5.5 miles away, averages about 7 days of 90°F or more in both July and August, and August is the hotter month, with an 84°F average high. July nights fall to about 57°F, so a tent in a Lake Grove spare room cools off on its own once the lamp moves to night hours.
From October on, the job changes. October averages 79 percent humidity, and lows sit near 36 to 37°F in December and January. A tent in a heated room runs much drier than the outdoor air, but a garage or unheated basement takes in the cold and damp. A flower room there needs a dehumidifier, a thermostat-controlled heater, and a fan that keeps running after lights-out.
Heater safety: use one with tip-over and overheat shutoff, plug it straight into a wall outlet (not an extension cord or power strip), and keep it a few feet from tent fabric and plants.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 48 | 53 | 58 | 64 | 71 | 76 | 84 | 84 | 78 | 65 | 53 | 47 |
| Avg low °F | 37 | 38 | 40 | 43 | 48 | 53 | 57 | 58 | 53 | 47 | 41 | 36 |
| Humidity % | 87 | 66 | 55 | 61 | 69 | 79 |
Highs and lows: NOAA 1991 to 2020 normals, Oregon City station (5.5 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.
Clackamas County outdoors: pick the finish line
Oregon counts plants by household: 4 per home, however many adults live there, so four adults in one house still share 4 plants. Start seeds March 14 to 28 and plant out April 25, when nights begin to average 45°F; the safe last-frost date of April 11 is behind you by then.
The early first-frost date, October 30, is about 188 days after planting, so frost seldom forces the harvest. The air does. Nights average 50°F or warmer only until September 29, right as the humidity climbs. Pick plants whose flowering time ends with September, give each of your 4 room for wind to pass through, and keep a cover ready for any that run long.
| Last spring frost | Mar 18 in a typical year, Apr 11 to be safe (later only 1 year in 10) |
|---|---|
| First fall frost | Nov 18 typical, as early as Oct 30 (1 year in 10) |
| Frost-free season | about 244 days |
| Nights stay 50°F or warmer | May 27 to Sep 29 |
| Start seeds or clones indoors | Mar 14 to Mar 28 |
| Move plants outdoors | Apr 25 or later |
A small city, a quiet log
Lake Oswego has about 41,000 people, and faces repeat: at the Lake Oswego Farmers' Market, at the Wednesday Concert Series, along the paths at George Rogers Park. With only 4 plants a household, each plant's record carries weight, and a single season can teach more than it seems.
Canna GLAP encrypts those grow records on your phone before they upload. Someone inside our servers would find only scrambled Lake Oswego grow data and no key. Who sees your numbers stays 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 Lake Oswego ask
When should I harvest outdoor cannabis in Lake Oswego?
Aim for the end of September. Humidity averages 69 percent that month and 79 in October, and nights average under 50°F after September 29.
When can I plant cannabis outside in Lake Oswego?
April 25 or later, after starting seeds March 14 to 28. The safe last-frost date is April 11, and nights begin to average 45°F on April 25.
How many cannabis plants can I grow in Lake Oswego?
Oregon allows 4 plants per household, however many adults live there.
Growing near Lake Oswego
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