CannaGLAP

Grow cannabis in Roanoke, VA

Growing cannabis in Roanoke: a wet September, then a fall that cools in a hurry

Fall comes to Roanoke in a rush. At the regional airport station, 3.6 miles away and 1,175 feet up, the average night falls from about 59°F in September to about 48°F in October, a drop of 11 degrees in one month. Afternoon highs slide from 80°F to 70.

That drop lands on the dampest air of the months measured. September averages about 79 percent humidity and October still about 72. When your plant's final two weeks fall inside that change, do you know how cold and wet its buds are at dawn?

Virginia home grow rules (as of October 2026)

Adults 21 and over: yes. Plant limit: 4 per household.

Main place of residence; not visible from a public way; each plant tagged with your name and ID number. Source: Va. Code 4.1-1101. Local rules (landlords, HOAs, city codes) can add more; this is a summary, not legal advice.

Roanoke indoors: watch the gap when the lamp goes off

Fall is the season to manage the dark hours. In a garage off Williamson Road or a basement in Grandin Village, an October room can run much cooler than the lit tent, and when the lamp switches off, the canopy cools quickly and the moisture in the air settles on and inside dense flowers. Keep the dark-period temperature within a few degrees of the lit period with a small heater, and let a dehumidifier run through the night.

Summer heat here is steady rather than extreme. July averages about 12 days at 90°F and August about 8, with highs near 88°F and 87°F. Nights hold near 67°F in July, so putting the lamp on the night shift helps less here than in a dry climate. A tent in a room the air conditioner reaches, with the exhaust sending warm air out of that room, does more.

Humidity builds the whole way through: about 64 percent in June, 71 in July, 74 in August and 79 in September. Treat a dehumidifier as part of the flower setup from the start, and keep a fan moving air under the canopy as well as across the top.

Winter is mild by comparison. January lows average about 29°F, with roughly 77 freezing nights a year. Raise pots off a cold slab and set seedlings on a heat mat, and the season gives little trouble.

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.

MonthJanFebMarAprMayJunJulAugSepOctNovDec
Avg high °F475159707784888780705950
Avg low °F293138465563676659483832
Humidity %716471747972

Highs and lows: NOAA 1991 to 2020 normals, Roanoke Rgnl Airport station (3.6 miles away). Humidity: Open-Meteo historical model data, average daily humidity in 2024, for the months shown. Planning averages, not a forecast.

Roanoke outdoors: four tagged plants and an early finish

Virginia allows 4 plants per household, at your main place of residence, kept where they are not visible from a public way, and each plant must carry a tag with your name and ID number. Before you pick a spot, stand on the street and look back at it.

Sow from March 7 to March 21 and move plants out on April 18. The last frost usually comes around April 3, and nights average 45°F from April 11. You then have about 183 days before an early frost on October 18, or November 1 in a typical year, but the season that matters ends sooner: nights stop averaging 50°F after October 10. Choose mold-resistant strains that finish in late September or early October, thin each plant's interior, and harvest before the cold, damp mornings settle in.

Last spring frostApr 3 in a typical year, Apr 18 to be safe (later only 1 year in 10)
First fall frostNov 1 typical, as early as Oct 18 (1 year in 10)
Frost-free seasonabout 210 days
Nights stay 50°F or warmerApr 28 to Oct 10
Start seeds or clones indoorsMar 7 to Mar 21
Move plants outdoorsApr 18 or later

The details of your four, kept private

Roanoke is a city where you run into people: at the Historic City Market on Market Street, on a First Friday downtown, at a festival in Elmwood Park. A neighbor or another grower may ask how your plants did, and what you tell them is your call. Your log holds the full version, the one a 79 percent September made you earn.

Your grow records are encrypted on your phone by Canna GLAP before they upload. A break-in at our servers would turn up Roanoke grow records in a form no one could read, with no key stored beside them.

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 Roanoke ask

When should I harvest outdoor cannabis in Roanoke?

Aim for late September to early October. Nights stop averaging 50°F after October 10 and average about 48°F for the month, and an early frost can arrive by October 18.

When can I move cannabis plants outside in Roanoke?

April 18, after sowing indoors between March 7 and March 21. The last frost usually comes around April 3, and by April 18 it has passed in about nine springs out of ten.

Do I need a dehumidifier to grow cannabis in Roanoke?

For flowering in late summer and fall, plan on one. August averages about 74 percent humidity and September about 79, the highest of the months measured.

Growing near Roanoke

All Virginia cities · Every state where adults may grow at home