Let’s start with the perfect growth temperatures for Cannabis – When we first started growing (some 20 years back) We didn’t have Dr-Google to run to when we had a problem within our grow room. What we had was “the grow bible” This was a paperback go-to book for growers of all sorts and sizes. Inside this little book of knowledge gave us a generic idea of where the grow room should sit temperature-wise and that was 85F. Over the years of cultivating and in addition knowing more about the strains we are growing, we are able to dial in room temperatures on a completely different level these days. In our grow rooms we start our clones off at 85F-87F.
These temperatures are set for our day and night temperature par levels. What this does is help keep the plants very warm all the way through the plant, the pot, and whatever medium you choose. The warm temperatures help the roots want to move around through that warm dank soil. We keep this temperature on point for the first 7days of cultivation. After that, we start to drop temperatures 1F-2F per day until we are down to 80F. This should take another 5-7days – keep the 80F for the rest of your veg cycle.
Now it’s time to flip the light cycle on these clones and get ready for the flower stage. The first week of flower we maintain the 80F and don’t change much because the plants are transitioning into flower cycle and are in shock, we don’t want to punish them anymore. After the first week of flower completes your plants can handle a little change so we are going to start dropping temperatures once again. In our grow rooms starting in week 2 of flower we are dropping the temperatures 1F-2F every other day for around 1 week until we are at 75F-76F. These temperatures can maintain for another 4 weeks of your flower cycle.
Depending on the strain you are growing you will have longer or shorter flowering times. The next step is customized for each strain. In our grow rooms during the last 3 weeks of flowering time we will start dropping temperatures once again. We will lower temps 1F-2F for 1 week bringing the room temperature to 72F. What these cool temperatures start doing is shocking the cannabis plant so lightly that she starts oozing more THC / FROST / BLING / RESINS. We all like that part of the plant but you have to do everything with care and a gentle touch. Reasoning behind that is your cannabis plant will go into shock. Every time your cannabis plant goes into shock she doesn’t grow for around 7 days. HANDLE YOUR PLANTS WITH CARE.
Now the next step is for the far experienced grower and will change the colour of your bud from green to purple. If you know exactly what strain you are growing you can alter its colours by dropping temperatures in the last 7days of flower to a staggering 65F. This is going to shock your plant to a different level where she will actually change colours on you. Please keep in mind these practices are within our group of cultivators and are the tips and tricks that “the grow bible” never taught us. : )
Watch for hot spots within your grow room, move your thermostats around and give yourself a clear idea of where the heat is and is not in your room. In our grow rooms we have 6 thermostats per room staggered throughout. We place thermostats around the top of the flower canopy; we also place thermostats on each end of the room. It’s always good practice to see how long it takes your room to cool from opposites sides when your air conditioner turns on.