Low humidity (dry air)

Humidity below your week's chart range: leaves dry at the edges, the plant drinks fast and spider mites get a head start.

Symptoms

• Humidity below the chart range for your week.
• Dry, crispy leaf edges; leaves may curl upwards.
• The plant drinks fast and the medium dries quickly.
• Spider mites more likely.

Quick checks

• Check humidity at canopy height, day and night, against the chart.
• Check temperature at the same time.
• Check leaf undersides for mites.

How to fix it

1. 1
   Environment

   Slow the air or add moisture

   Slow the extractor (keeping temperature in range), switch off any dehumidifier, or add a small humidifier.

2. 2
   Environment

   Bring temperature in range

   Cooling a hot tent raises relative humidity.

3. 3
   Prevention

   Follow the chart

   70–85% in growth and early flower, falling to 40–45% by flower week 8.

Likely causes

• Winter air or heating drying the room.
• Extraction too strong for the space.
• Hot tent: warm air holds more water, so relative humidity falls.
• Dehumidifier running when it isn't needed.

What to avoid

• Don't push humidity up in late flower: the chart drops it for a reason (mould).
• Don't leave standing water in the tent as a humidifier.

Prevention

• A hygrometer at canopy height.
• Seasonal fan adjustments.

Monkey products that can help

Stress

Can help the plant cope with abiotic stress. Support only.

2 ml per 10 L every week. Always add it to the water first and mix thoroughly before adding anything else.

View product →

Products support a healthy plant. They don't replace fixing the cause.

When to get help

If you can't keep humidity in range, email info@monkeynutrients.co.uk with your tent size and kit.

Related problems