This is a touched up version of a blog we did a few years ago where we explain the importance of maintaining certain temperatures during a plants lights off period.
Why do my plants look deficient everything's the same as always?
Well, when your lights turn off what happens is the temperatures start dropping and the root zone activity slows the plant goes into a resting state (respiration) however when the temperatures drop below 15 C degrees some plant's metabolic system will shut down causing stunted growth and restricted nutrient uptake which can display some potential deficiencies with new growth. Ring any bells?
If your grow room is subjected to ambient weather conditions you will find this is a major issue and without corrective action, your plants will go downhill very quick. You cannot ignore the minimum requirements.
Below 15 degrees and its full shutdown, every night!
What should my temp be at night?
18.5 -21.5 is the perfect lights off range for the environment and the root zone.
What equipment can i use to fix this problem?
Most hobbyists use an oil (column/bar) heater, these units come prebuilt with thermostat controllers which will allow you to maintain a minimum and a maximum temperature during lights off, they are reasonably priced but they consume an unreasonable amount of power, especially if you're only growing in a small space
Global Gardens have rebranded their very popular low wattage heat bars and renamed them Hot rods, they work by raising ambient temps by 10-12 degrees, they work great are energy efficient and cost effective. Click this link to learn more.
Ask us in store which size will best suit your grow room or grow tent or submit a comment.
Cultiv8 have a range of various sized Heat mats that will also raise the ambient temperatures by 10 degrees. I have seen some growers wrap their fabric pots with heat mats during the night or place them under 50-70L DWC hydroponic systems that have a thermostat controller connected to them. This is a great low cost option for those using them for propagation or just have a really small grow tent.
For large warehouse style grows you will want to explore the benefits of climate control systems as they offer both cooling, heating and dehumidification features but come at a significant cost and they can consume some serious power. These systems are by far the best way to control your environmental conditions but are not always an option, depending on the location of your grow room or grow budget.
What will happen if I do not correct my temperature?
If you do not correct your temperature, it will only be a matter of time before the plant starts to shutdown and suffers a slow death. If the plant is already flowering and this is happening, then its not going to be a good yield at all.
As a generalisation; the warmer the environment, the faster plants grow, the colder the environment, the slower plants grow.
The science is solid on temperature and plant growth, so rather than pulling your hair out trying to figure out what could be causing problems, just set it up from the beginning, then it will never be a concern.