Ask the Doc: How Does Temperature Affect Plant Growth?
A lot of growers ask, "what's the best light to use" or "what's the best nutrient" or "what's the best soil". But to really maximize and get the most out of your grow, you should know that it's not the best thing that you're using but it is what is the most scarce, what is the most limiting that is going to determine your maximum rate of growth. So check out our video about limiting factors so that you can get the most out of your plants.
Temperature can limit your plant growth in many ways. Now the first one most people know is that's the air temperature around your plants. That should be about 77 degrees Fahrenheit for your optimal growth. If your grow area is less than 70 degrees during the daylight hours or above 80 degrees your plants are gonna have slower growth. Now you're not gonna see this as a yellow leaf or anything obvious and so that's why I recommend every single grower should have a thermometer in the grow room so that you know what the temperature is.
Now this thermometer has an excellent feature, it has a min/max button so you know what the minimum and maximum temperature is throughout your grow cycle. You can make sure that your plants are surrounded by the optimal air temperature. Now humidity is also related to temperature, the warmer the air, the more moisture it can hold. And this also has a humidity sensor and you want your humidity to be about 50 to 60 percent around your plants. Now a good idea for any grow area is to also have a fan because the hottest area is probably gonna be right around your light that's probably the main source of heat in your grow area so fan will distribute the temperature it's also going to help distribute the humidity in your grow area.
Now something that many growers might not be aware of is that the root temperature needs to be about 10 degrees cooler than the above-ground temperature. And so this thermometer has an excellent feature, it has this little probe and this actually can take the temperature as well. And so you can take the probe and you can put it down here at the base to see what it is or you can actually stick it right in the dirt and see what the temperature your soil medium is. If your medium is not about 10 degrees cooler than the above-ground part then you're going to get slower growth.
Now the third way that temperature can limit your growth is with the day and night temperatures. Most plants are going to regulate what's going on with the temperature and so indoors, a problem many growers have, is that when they turn their lights off they also turn the ventilation fans and the temperature stays relatively constant in the grow room and that's not the best for plants. Your nighttime temperature should be dropping about 10 degrees Fahrenheit compared to your daytime temperature. Especially if you have plants that are flowering because if the temperature doesn't change plants might be a little stressed or not understand what's going on and you're going to get a poor flowering response if you don't have this drop in the nighttime temperatures.
So make sure the air around your plants is 77 degrees during the day make sure the roots are about 10 degrees cooler than that and make sure you have a significant about 10 degree drop from daytime and nighttime and that way temperature will not be a limiting factor for you.
If you're looking for more information, check out HTGSupply.com/InformationCenter and of course there's lots of videos on Instagram TV and YouTube. Thanks for watching. Good Growing!