REDUX: Heat Stressed Plants

Heat Stressed Plants

Cultivating plants indoors during the hotter months poses a significant challenge for growers who lack climate control systems. 

The responsibility of managing temperature falls on your shoulders, compelling you to employ various methods and tricks to mitigate the rising heat. In this blog, we keep it short but explore the critical issue of heat stress and environmental temperature for those growing in hydroponics grow rooms or grow tents.

Heat Stress in Vegetation and how to fix:

During the vegetative phase, leaves may curl upwards, creating a canoe-like appearance. This symptom worsens with high temperatures and low humidity. To address this, consider lifting the light and reducing the wattage output. Always go for PAR (Photosynthetically Active Radiation) over raw power, dim/adjust light intensity, and administer a weak foliar spray of potassium nitrate as the lights are due to turn off.

Excessive heat on the plant canopy can disrupt stomata function, reducing carbon dioxide absorption. Similar remedies apply, and if dimming isn't feasible, supplementing with CO2 is absolutely a must.

Maintaining the root zone temperature between 18.5°C and 22°C is crucial. Counteract temperature spikes with frequent nutrient solution replenishment or microbial additives that fortify roots against temperature variations. Keep airflow running over the growing containers or growing pots. We as growers understand that sometimes you have to grow on a budget and spending money to fix problems is not feasible, in cases like this use some intuition get some ice in a bucket and have a clip fan blow over it to help cool down the grow bag or pot.

Heat Stress in Flowering and how to fix:

In the flowering phase, heat stress can threaten harvest outcomes. The number 1 rule here is avoid over feeding, drop the concentration of food by 20%. Heat-stressed flowers may exhibit "fox tailing" type growth from existing flowers, leaf and bud bleaching is almost a certainty. Dimming lights is a must, raising fixtures, and enhancing air circulation can mitigate shifts in floral morphology.

Heat Stress

A few A-Grade tips.

Integrated Pest Management treatments (IPM)

Having Pest treatments nearby to combat any infestations occurring during the rising temp.

Temperature Monitoring Tools

Climate control systems, fan controllers and hygrometers.

Energy Efficient Lighting

Using quality Full spectrum LED grow lights always seek out a reputable brand if you have the option to.

Ventilation Systems

Always exhaust using the right fan for the space, not enough or too much airflow will only compound the stress the plants are experiencing. Using Intake fans as well as air circulating fans help massively.

Hopefully if you have experienced a heat stress issue its not too late for you to do something. Always go to your local hydro shop or gardening centre for some advice make sure the light source you get is the best full spectrum LED grow light you can use because there are so many bad ones claiming to have the good diodes yet not informing you that they are the lowest grade of that LED diode, and there’s 27 grades! Always do you research.

If you do successfully avoid or remedy the issue we hope you grow some big plants that will return you a heavy harvest and then, do it all over again. :)




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Other Tutorials

What Should My Humidity Be?
Heat Stressed Plants
Understanding VPD - The key to hydroponics
Hydroponics and Grow Room Humidity
Grow Room Tip - Night Time Temperatures

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