The Impact of Extreme Temperatures on Greenhouse Plants: What to Watch For

Riya Chhabda

Greenhouses are designed to offer plants a controlled environment, protecting them from the unpredictable nature of outdoor weather. However, even within these protective structures, extreme temperatures can pose significant challenges.

In this blog, we'll delve into the effects of temperature extremes on greenhouse plants and the signs that gardeners should be vigilant about.

1. The Role of Temperature in Plant Growth

Temperature plays a pivotal role in various plant processes, including photosynthesis, respiration, germination, and flowering. It's a driving factor that determines how quickly a plant grows and how well it thrives.

While plants have a certain degree of tolerance, extreme temperatures can push them beyond their comfort zones.

2. The Perils of Excessive Heat

a. Wilting and Drooping:

  • High temperatures can cause rapid water loss from plant leaves, leading to wilting. If not addressed, this can progress to irreversible damage.

b. Sunburn:

  • Just like humans, plants can get sunburned too. This is evident when leaves turn white or brown due to the destruction of chlorophyll.

c. Reduced Flowering:

  • Excessive heat can hinder the flowering process in many plants, leading to reduced yields, especially in fruiting plants.

d. Faster Maturation:

  • Plants may mature faster than usual, often leading to smaller produce or reduced quality.

3. The Challenges of Extreme Cold

a. Frost Damage:

  • Frost can damage plant cells, leading to blackened or mushy foliage. Tender plants are especially susceptible.

b. Stunted Growth:

  • Cold temperatures can slow down metabolic processes, leading to slower growth rates.

c. Dormancy or Delayed Germination:

  • Some seeds may enter a prolonged dormancy phase or delay germination until warmer temperatures prevail.

d. Leaf Drop:

  • Some plants may shed leaves as a protective mechanism against cold stress.

4. Signs to Watch For

a. Leaf Discoloration:

  • Yellowing, browning, or whitening of leaves can indicate temperature stress.

b. Bud Drop:

  • Plants may shed buds prematurely in response to temperature extremes.

c. Root Rot:

  • Overwatering during cold spells can lead to root rot, as plants take up water at a slower rate.

d. Pests and Diseases:

  • Stressed plants are more susceptible to pests and diseases, so an increase in these can be an indirect sign of temperature issues.

5. Mitigating the Impact of Extreme Temperatures

a. Shade Cloths:

  • These can be used during hot spells to protect plants from direct sunlight and reduce internal temperatures.

b. Heating Systems:

  • For cold nights or winter months, heaters can help maintain a consistent temperature.

c. Regular Monitoring:

  • Invest in good quality thermometers and possibly automated alert systems to keep track of greenhouse temperatures.

d. Proper Ventilation:

  • Ensure your greenhouse has adequate ventilation to regulate temperature and prevent overheating.


While greenhouses offer a protective shield, they are not impervious to the challenges posed by extreme temperatures.

By understanding the potential impacts and being proactive in monitoring and intervention, gardeners can ensure their plants remain healthy and productive.

In the dance between nature and nurture, knowledge and vigilance are the keys to harmony.

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