Growing Cannabis in Different Climates

Growing cannabis in different climates comes down to matching timing, site and care to the weather you have. Heat speeds water loss, cold slows or stops growth, humid air keeps leaves wet and strong wind dries and breaks plants. Each one calls for a different response. Kind Seed Co draws the steps below from Extension guidance.

The sources here are general garden and landscape guides, plus one Extension page on cannabis, so read their findings that way. Start with your own yard: our guide to garden microclimates shows how warm walls, low spots and shade change conditions within one site.

Know Your Climate First

Start with the season you actually have. USU Extension in Utah advises weighing the number of frost free days when you choose what to plant.

That number tells you how long the plants have outdoors before a hard frost. USU notes that hard frosts stop plant growth. Day length counts as much as temperature, because USU describes cannabis as a plant that responds to short days, starting to flower once nights grow to roughly match days.

Dealing with High Winds

Strong wind dries plants and can break them. NC State’s Gardener Handbook warns that strong wind can snap stems and branches and pull water from a plant.

MSU Extension in Michigan describes screening placed to intercept prevailing winds, and notes that plants with several stems can be tied for support. MSU also ties winter drying to sunny, windy days, when leaves lose water more quickly than roots can replace it. Our page on windbreaks for outdoor cannabis covers building one.

Growing Cannabis When It Is Cold

Cold slows growth, and a hard frost ends it. MSU Extension separates chilling damage, from temperatures above freezing that are still low enough to harm tissue, from freezing damage, which is worse.

MSU says a sudden drop is the main driver of chilling damage, and that plants native to warmer regions handle less cold once moved north. Freezing damage shows as blackened, browned or bleached tissue.

Steps for a cold climate:

1. Count your frost free days. USU names this as a key factor when choosing what to plant.
2. Plant once the soil warms. Avoid setting young plants out ahead of a late cold snap.
3. Mulch the root zone. MSU says an even mulch layer helps prevent rapid swings in soil temperature.
4. Watch the forecast near harvest. USU notes hard frosts stop growth, so plan the finish around your first frost date.

Cannabis Cultivation in High Humidity

Humid air keeps leaves and buds wet. MSU Extension warns that air above 85% relative humidity can favor fungal pathogens, because water lost by the leaves stays on them.

UMass Extension explains the physics behind it: cooler air holds less water, so humidity climbs as air cools at night, and water condenses on surfaces once they fall under the dew point. Both sources describe greenhouses, so read this as general humidity physics rather than outdoor research.

Steps for a humid climate:

1. Give plants room. UMass lists adequate spacing among the ways to cut humidity.
2. Water in the morning. UMass advises watering early so leaves and media dry by evening.
3. Keep air moving. UMass says leaves that move slightly show adequate air movement.
4. Thin dense growth. Open up the centre of each plant so air reaches it.
5. Check after rain. Look inside dense buds and remove any that stay wet or show mold.

Growing a Successful Crop in the Heat

Heat drives water loss. Arizona Cooperative Extension says high temperatures speed water loss from plants and soil through higher evapotranspiration.

Arizona adds that heat often comes with drought and that heatwaves are runs of days far hotter than normal. A heatwave early in the season can cause damage at lower temperatures than one in summer. Plants beside asphalt or reflective walls are at greater risk than plants surrounded by other plants or bare soil.

Arizona lists wilting, drying and browning leaves, leaf drop, sunscald and little or no new growth as signs of drought and heat damage. Our page on cannabis heat stress covers the plant side in detail.

Steps for a hot climate:

1. Water deeply. Arizona advises watering to the depth of the root zone and letting the soil dry somewhat between waterings.
2. Mulch the soil. MSU notes mulch conserves soil moisture and evens out soil temperature.
3. Site plants away from heat sinks. Arizona flags asphalt and reflective surfaces as higher risk.
4. Check soil moisture through heatwaves. Water loss climbs with heat, so check more often.

Watering in the Heat

Water to the root zone, not just the surface. Arizona Extension advises watering as deep as the roots and allowing some drying between waterings.

How much and how often, it adds, depends on soil type, plant size and rainfall. Too much water causes its own trouble. MSU warns that poor drainage leaves roots without white tips and short on air.

Exposure to Sunlight

Day length decides when outdoor plants flower. USU Extension ties the start of flowering to nights lengthening until they roughly equal the days.

That means your latitude and planting date shape the season as much as temperature. In strong sun, MSU notes that leaves suddenly exposed to full sun during hot, dry spells can scorch, so move plants into full sun gradually.

Seeds for Your Climate

Choice of plant matters too. Our guide to seeds that suit your climate covers matching what you grow to your season.

Container Gardens

Containers heat and dry faster than the ground. Arizona notes that heat speeds soil evaporation, and a pot has less soil to buffer it.

Use larger containers where you can, since more soil takes longer to heat and dry. Shade the sides of pots in strong sun and check moisture more often than you would for plants in the ground. Make sure every pot drains freely after watering.

Troubleshooting

When the weather turns, act on the cause, not only the plant. These cases come up most.

Leaves curl in a heatwave. Arizona lists wilting and drying leaves as heat signs. Water deeply and shade the plants through the hottest hours.

Plants stall after a cold night. MSU links chilling damage to sudden drops. Mulch the root zone and wait for new growth before changing anything else.

Mold shows after a week of rain. MSU links RH above 85% to fungal trouble. Thin dense growth and remove any affected buds.

Wind snaps branches. NC State notes high winds can break stems. Tie up the damaged branch and add screening on the windward side.

Flowering starts too late for the season. USU links flowering to the point where dark and light periods even out. Count your frost free days before you plant next year.

Start Your Next Grow

Pick seeds that suit your season. Browse feminized cannabis seeds when you are ready.

Sources

• University of Arizona Cooperative Extension AZ1876, Drought and Extreme Heat: Plant Responses and Landscape Maintenance Practices: https://extension.arizona.edu/publication/drought-and-extreme-heat-plant-responses-and-landscape-maintenance-practices
• Utah State University Extension, Ten Frequently Asked Questions About Growing Cannabis: https://extension.usu.edu/crops/research/ten-frequently-asked-questions-about-growing-cannabis
• UMass Amherst Center for Agriculture, Food, and the Environment, Reducing Humidity in the Greenhouse: https://www.umass.edu/agriculture-food-environment/greenhouse-floriculture/fact-sheets/reducing-humidity-in-greenhouse
• Michigan State University Extension, Wollaeger and Runkle, VPD vs. Relative Humidity: https://www.canr.msu.edu/uploads/resources/pdfs/vpd-vs-rh.pdf
• Michigan State University Extension E2996, Abiotic Plant Disorders: Symptoms, Signs and Solutions: https://www.canr.msu.edu/outreach/uploads/2018-files/e2996.abiotic%20plant%20disorders%20-%20symptoms,%20signs%20and%20solutions.pdf
• NC State Extension Gardener Handbook, Chapter 7 Diagnostics: https://content.ces.ncsu.edu/extension-gardener-handbook/7-diagnostics