ok, i'm at my girlfriends appt so I dont have all the resources but...... unless you are growing in an air compressor (or a vacuum) there will be no effect of pressure on your plants. period. If there is a 1 psi (pound per square inch) difference between the outside of your cabinet and inside that means there will be a 10368 pound force on your cabinet walls (48" wide, 24"deep, 72" tall), and one psi is NOTHING.
My buddy oversees the greenhouse at The University of ******* and they are doing experiments in TOTALLY sealed greenhouses. They have a system that moves the roof tiles to regulate sunlight, pumps that monitor pH, industrial natural gas burners to keep CO2 constant, ppm readers that regulate the aero nutrient solutions, swamp coolers to adjust humidity, and a team of people to oversee that. The computer system has 18 variables. Not to mention every-other-day they send their solutions out to a lab to get a spectrum analysis readout on whats in their water.. to see EXACTLY what the plants are using. They have to measure the leaves every 3 hours 24/7 to keep track of growth.
They're doing this to figure out how to grow and propagate food in sealed environments (like pods on the moon, space station, or mars). The limiting factor is the pressure and atmospheric conditions people can take, not plants.
Anyhoo.... its good that you have your light sealed from the enviro and air being pushed through it. Good idea. How hot can you get the cabinet at the height of a top cola would be (with light, light fan, and an internal circulating fan going)? Thats the ONLY number you should be worried about. Again, less than 90 you are GOLDEN, if not your system just wont work with you're doing unless you are perpetually wasting gas (which is what you want to do). I know FOR SURE that 85 degrees with +-1500 ppm CO2 rocks. I understand right next to the glass is really hot but who cares? what matters is what the top of the top cola feels right before harvest. I know you dont want to hear this again, but you really could grow one really nice plant in that space with a 250Watt HPS and then heat issues disappear. But don't ask me.. I'm new at this whole botany thing.
My buddy oversees the greenhouse at The University of ******* and they are doing experiments in TOTALLY sealed greenhouses. They have a system that moves the roof tiles to regulate sunlight, pumps that monitor pH, industrial natural gas burners to keep CO2 constant, ppm readers that regulate the aero nutrient solutions, swamp coolers to adjust humidity, and a team of people to oversee that. The computer system has 18 variables. Not to mention every-other-day they send their solutions out to a lab to get a spectrum analysis readout on whats in their water.. to see EXACTLY what the plants are using. They have to measure the leaves every 3 hours 24/7 to keep track of growth.
They're doing this to figure out how to grow and propagate food in sealed environments (like pods on the moon, space station, or mars). The limiting factor is the pressure and atmospheric conditions people can take, not plants.
Anyhoo.... its good that you have your light sealed from the enviro and air being pushed through it. Good idea. How hot can you get the cabinet at the height of a top cola would be (with light, light fan, and an internal circulating fan going)? Thats the ONLY number you should be worried about. Again, less than 90 you are GOLDEN, if not your system just wont work with you're doing unless you are perpetually wasting gas (which is what you want to do). I know FOR SURE that 85 degrees with +-1500 ppm CO2 rocks. I understand right next to the glass is really hot but who cares? what matters is what the top of the top cola feels right before harvest. I know you dont want to hear this again, but you really could grow one really nice plant in that space with a 250Watt HPS and then heat issues disappear. But don't ask me.. I'm new at this whole botany thing.
