Like people, plants can also “catch their death” or so to speak.
When you walk into your grow room with just a t-shirt on do you feel cool? If you do then it means your plants are likely getting too cold, especially when the lights are off.
Temperature Control Tips
Here are some good tips to maintaining a good temperature in the colder months:
Give the final feed at least an hour before the lights switch off.
Unlike in nature where you have sunrise and sunset where the temperature drops gradually in grow rooms which use artificial lighting it usually is switched off automatically on a timer, all at once which can cause a sudden room temperature drop. Giving the final feed at least an hour prior to the lighting off time will allow the plant to uptake a lot of the moisture so when they sleep the roots ae not sitting in a wet environment. Imagine someone hosing your shirt and then making you sleep in it, you will likely get a bit sick right? Well same applies to plants.
Make sure your nutrient reservoir maintains 20-22 degrees Celsius
There are a couple of good reasons to make sure your water barrels are the correct temperature, the first is as cost effective as it is wise. Nutrients and additives can “fall out” if the water is too hot or cold when adding them. This basically means they will no longer be properly chelated and mixed with the water making it difficult for the plant to uptake through the roots and use the nutrients to their full potential. With the expensive hormone based additives it can actually cause the hormone to be inactivated, rendering the additive useless. With the hormone types of additives it is especially important to maintain barrel temperature at 20 degrees.
The second reason is shock factor. Too cold or too hot nutrient solutions will shock the roots system of your plants.
For a 200L nutrient barrel we recommend using a 300W thermosafe water heater, this will be the most efficient for maintaining the correct temperatures http://hydro4u.com.au/product/water-heater-300w-glass/
Get yourself a small oil column heater for your plants off light cycle or sleep periods.
You really don’t want your room temperature to ever drop below 20 degrees Celsius, this is especially important during the vegetative grow stage, run it on a thermostat controller to ensure it doesn’t overheat. We usually recommend 20-22 degrees variance during lights off times. http://hydro4u.com.au/product/thermostat-ts2400-hot-cold/
Stagger your light cycles on/off
You can try to stagger your lights on and lights off phases over say a half hour period to try simulate the sunlight cycles, we suggest you use the HPS (orange) globes during the staggering periods. http://hydro4u.com.au/product-category/lighting-ballasts-shades/
Invest in a thermometer and hygrometer to always be up to date with your room temperatures and humidity
Remember always, a cold plant is more susceptible to sickness and deficiency caused by root disease. Sick plants are more likely to be attacked by pests. So if you have a pest issue, look into climate as the root cause!