On that note, I'll start this journal off by telling you my details. | |
Cabinet:
My cabinet is made of white melomine. Great stuff. It doesn't warp, you can write on it with a dry erase marker & it wipes right off. Perfect for keeping notes. The cab measures 55" high x 29" wide x 22" deep. This gives me 4.4 square feet & 20.3 cubic feet.
Ventilation:
This is one of the most important things to control during a grow.
If the temp is to high, the plants can transpire so much, that the salts from the nutes can build up on the leaves & burn them. Keeping the humidity high can help, but then you'll still have to deal with the possibility of the plants stretching, another thing high temps can cause. During the vegetative portion of a grow, the plants do best with temps between 70f & 79f.
During flowering it's ok to let the temps go to as high as 90. This can actually cause the plants to produce more trichomes as a form of protection from the heat.
Ventilation also controls your humidity. During the veg & flowering stretch, the plants will do best with the humidity between 50% & 75%. Lower temps & higher humidity will help to keep the spacing between internodes close. Especially when the plants are first starting out.
During the flowering stage of the grow, the humidity needs to stay below 50% to avoid mold forming on the buds.
The lower humidity will also make your plants transpire more. More transpiration means more uptake of nutrients which will give you bigger colas. Be careful though. Low humidity & high temps during flowering can be a plus, but it can also burn the hell out of your plants from to many nutes if your not very careful.
If you start to see any burning of the leaves, lower the ppm of the nutes immediately. You might even have to flush the plants to remove the excess nutes.
I have 1, 4" exhaust hole with a 4" 104cfm axial fan pulling air out of the top of the cabinet & then blowing it into the ceiling rafters. I also have an ozone generator blowing ozone into the rafters for odor control. Works great.
I have 1, 4” passive exhaust hole in the floor of the cabinet with a 4" black pvc pipe going through a hole I drilled through the sub floor of my home. This allows me to bring cool air into the cabinet from the crawl space beneath my home.
I also have a 4" passive exhaust hole in the side of the cabinet, just above the floor that pulls warm air from inside my home.
The winters here get extremely cold. We already have 6 feet of snow on the ground & the temps have dropped to as low as -14f. So keeping my cabinet within the proper temp ranges is a little tricky when 12/12 starts. The problem is keeping the cold air being pulled in from under the house getting the cab to cold during lights out. If I don't keep the cold air out, the temp drops into the 40's & that’s to cold for MJ. In the summer, the temp under the house stays in the 60's so it's not a problem.
So here's how I fixed the winter problem:
For 24/0 lighting, I tape over the hole in the side of the cab & leave the hole in the floor of the cab open 24/0. This lets cold air in continuously & keeps the temp pretty constant.
For 12/12 lighting, I mount another 4" 104cfm axial fan over the exhaust hole in the floor. I attach a 4" dryer vent cap to the top of it & untape the hole in the side of the cab that was closed during 24/0.
The exhaust fan mounted to the floor of the cab is on the same timer as the lights. So when the lights are on, the fan turns on pushing the hinged flap on the vent cap open, allowing cool air into the cab during lights on.
When the lights turn off, the fan shuts off & the vent cap closes. With the vent cap closed, the air gets pulled in through the exhaust hole in the side of the cabinet. The air that gets pulled in through the side is from within my house & is usually between 65f & 72f. Kind of complicated, but it works to keep the temps steady.
On top of all that, I have a circulation fan blowing air 24/0 & an ultrasonic humidifier running 24/0. The humidifier has a 2-gallon res. & I have to fill it twice a day.
Because of the small size of my cab, I point the circ fan away from my plants while they’re young. This still gives plenty of air & plant movement. If I point the fan directly at the plants, the leaves the fan hits directly, get nute burned. What happens is the leaves transpire so quickly; the nutes build up within the leaves & on the surface of the leaves causing them to burn & dry out. It only takes a light breeze, not a full-blown gale for your plants to get fresh air & strong stems. |