For New Transplants
Use young plants: ≤ 45 days old, shoots of maximum 10 - 12 cm. Young plants tolerate up to 48°C.
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Irrigate only at sunrise, within 3 hours – it’s the coolest part of the day.
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Opt for a plastic cover with 70% light diffusion; if not available, shading with chalk at 40 kg/Ha diluted in 2000 L of water is highly recommended
For Adult Plants
- Short and frequent irrigations in the mid-day, respecting an interval between irrigations of at least 15 minutes to avoid root asphyxiation.
- Reduce EC by 0.5 mS/cm during the heat wave – prioritise continuous transpiration for a cool microclimate rather than nutrient absorption.
- Last irrigation 1h30 before sunset, then 1 to 2 night irrigations (between 0h and 2h). Heat causes water loss of the substrate through evaporation even at night.
- Stop any de-leafing to avoid additional stress.
- Keep the side shoots near the flowering truss, they can replace wilted heads.
- Protect bumblebees: place the hives in 1m deep pits, cover them with polystyrene, then a damp cloth to cool the environment and maintain their activity (Image below).
- If available, activate external fogging (5 min every 30 min) or internal misting (4 min every 15 min).
- Keep the greenhouse closed, especially on the windy side, to preserve humidity. Low relative humidity (RH%) causes more damage than high temperatures.
Proactive management allows you to protect your yield and ensure your crop's resilience to extreme heat
Image : Bumblebees hive protection setup in Ceres Reasearch Station (2022)
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