Tips for Growing Cannabis in Summer

Growing cannabis in the summer can bring faster growth and higher yields, but it also comes with unique challenges, especially related to heat, humidity, pests, and mold. Here's a detailed guide with practical tips for indoor and outdoor grows to help you succeed in hot weather:

1. Control Temperature

Ideal range:

Day: 22–28°C (72–82°F)

Night: 18–22°C (64–72°F)

Too hot (>32°C / 90°F): Can lead to heat stress, stunted growth, and foxtailing buds.

Tips:

Indoor: Use AC, LED lights (less heat than HPS), and good airflow

Outdoor: Provide shade cloth during peak sun hours (12–3 PM)

2. Monitor Humidity Carefully

High humidity + high heat = mold risk

Target relative humidity (RH):

Vegetative: 50–70%

Flowering: 40–50%

Late flowering: 30–40%

Tips:

Use cannabis dehumidifiers in grow tents or rooms.

Improve air exchange with inline fans + carbon filters

Ensure lights off time doesn't cause condensation

3. Maximize Airflow

Heat + stagnant air = disaster (mold, pests, poor CO₂ exchange)

Tips:

Use oscillating fans at canopy level and under canopy

Avoid "dead air" pockets in grow room

Space plants adequately for air movement

4. Be Proactive with Pest Management

Warm weather = more spider mites, aphids, fungus gnats, whiteflies

Tips:

Use Neem oil, insecticidal soap, or biological controls like ladybugs

Keep the grow area clean and monitor with sticky traps

Inspect under leaves weekly

5. Hydration & Watering

Plants drink more in heat, but overwatering leads to root rot.

Tips:

Water early morning or late afternoon

Use fabric pots to prevent overheating and improve drainage

Consider adding silica supplements to strengthen cell walls

6. Use the Right Lighting (for indoor growers)

Avoid HPS/MH in summer – too hot

Use LED grow lights for lower heat and energy efficiency

Bonus:

Run lights during cooler night hours to balance heat loads

7. Choose Summer-Friendly Strains

Look for heat- and mold-resistant strains:

Sativa-dominant strains usually handle heat better than indicas

Popular options: Durban Poison, Amnesia Haze, Jack Herer, Cinderella 99

8. Clean Your Grow Room Before Summer

Prevent pest/mold infestations by sterilizing:

Walls, pots, trays, filters, vents

Check all electrical systems (fans, dehumidifiers, lights) for summer load

9. Use Light Traps

Summer = longer daylight. If using natural light indoors, blackout curtains or light traps prevent light leaks that can disrupt flowering.

10. Monitor and Automate

Use smart controllers (like TrolMaster or AC Infinity systems) to automate:

Temperature, humidity, CO₂, and light cycles

In summer, less is more — focus on plant health, airflow, and climate control more than packing your grow space with too many plants.