drzaius993
Active Member
Hey guys, been trying out my ultra-micro rubbermaid tub grow, and it hasn't been going well so far. My first attempt had some problems with pH, overwatering, and temperature (up to 95-100 degrees, i think
). The second time around, I was able to control for more things with a pH test kit, temp/humidity display, and more careful watering, yet I have still been met with stagnant growth and eventual death. The only two things I can think of that could have been adverse were the relative humidity (it was 20-30% most of the time) and the design of the grow box resulting in inadequate fresh air flow.
Since this is in the Design & Setup section, let's talk about that. Basically, it's two 18 gal rubbermaid tubs stacked on top of each other, with two 120mm/100CFM fans at either side of the top tub, both pushing heat out the sides. There are two passive intakes at either end of the bottom tub, and they are both roughly twice the area of the exhaust holes. The trick is that in order to keep the plant(s) as close as possible to the lights, I have to stack them on top of ridiculous things. In addition to them hindering airflow, I am worried that having the ventilation set up the way I do, the air will just be sucked more or less straight up through the intake towards the exhaust without passing over the plants. See the attached picture for what I mean. I have also tried flipping Fan A around so that the air goes in one side of the box and comes out the other.
Couple questions about my design:
1) Is it possible my plants were deprived of fresh air, or had the air sucked too quickly past them?
2) Is 2x100 cfm too much airflow? It does a good job of getting rid of heat but i'm worried it's harming my plants.
3) Is it possible the high CFM got rid of the moisture in the box too quickly, leading to the very low relative humidity?
). The second time around, I was able to control for more things with a pH test kit, temp/humidity display, and more careful watering, yet I have still been met with stagnant growth and eventual death. The only two things I can think of that could have been adverse were the relative humidity (it was 20-30% most of the time) and the design of the grow box resulting in inadequate fresh air flow.Since this is in the Design & Setup section, let's talk about that. Basically, it's two 18 gal rubbermaid tubs stacked on top of each other, with two 120mm/100CFM fans at either side of the top tub, both pushing heat out the sides. There are two passive intakes at either end of the bottom tub, and they are both roughly twice the area of the exhaust holes. The trick is that in order to keep the plant(s) as close as possible to the lights, I have to stack them on top of ridiculous things. In addition to them hindering airflow, I am worried that having the ventilation set up the way I do, the air will just be sucked more or less straight up through the intake towards the exhaust without passing over the plants. See the attached picture for what I mean. I have also tried flipping Fan A around so that the air goes in one side of the box and comes out the other.
Couple questions about my design:
1) Is it possible my plants were deprived of fresh air, or had the air sucked too quickly past them?
2) Is 2x100 cfm too much airflow? It does a good job of getting rid of heat but i'm worried it's harming my plants.
3) Is it possible the high CFM got rid of the moisture in the box too quickly, leading to the very low relative humidity?
