Cold stress

Cold roots (below about 15 °C) slow everything down and can cause purple stems and phosphorus problems. Common in UK lofts and garages in winter.

Symptoms

• Slow growth and slow drinking.
• Purple stems or leaf stalks; dark, dull leaves.
• Phosphorus-type symptoms.
• Medium staying wet for longer.

Quick checks

• Max-min thermometer for lights-off lows.
• Measure root-zone and floor temperature.
• Water temperature at mixing.

How to fix it

1. 1
   Environment

   Heat the dark period

   A small thermostatic heater keeps nights within about 5–8 °C of the daytime temperature.

2. 2
   Physical

   Lift containers off the floor

   Stand them on insulation or a raised platform.

3. 3
   Feed

   Use room-temperature water

   Never water with icy-cold water.

4. 4
   Support

   Support the plant

   Monkey say Stress helps the plant manage cold stress.

Likely causes

• Lights-off temperatures below about 15 °C.
• Containers on cold concrete floors.
• Big day-night swings.
• Cold intake air or very cold water.

What to avoid

• Don't feed more to fix cold-related symptoms.
• Don't let the dark period crash below 15 °C.

Prevention

• Winter checks with a max-min thermometer.
• Insulated floors.

Monkey products that can help

Stress

Monkey say silicon helps the plant manage abiotic stress such as cold. Can help, not cure.

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 lights-off temperatures above 15 °C, email info@monkeynutrients.co.uk for set-up advice.

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