Puzzled... Can anyone explain why?

Started to flower all the plants at the same time. They all went on 12-12 and I have noticed on the top shelf the flowers are a good week if not more in front of the bottom shelf. Can anyone offer an explanation.

1-The only contributing factors I can think of is the inlet fan is positioned at the bottom but the air is temp controlled so shouldn't be shocking them.

2-The cool tube has sucked a bit of dust into the glass housing and it needs a bit of a clean- could this be the reason?

3-I'm using C02 and as we are all aware as it's denser than air it falls, this would lead me to think that maybe the concentration of C02 may be reaching too higher level.

Any suggestions or ideas appreciated as bit stuck for space and would be using the grow room for drying obviously having harvest two weeks apart is going to make things difficult.

Could be co2, but it's more likely to do with your light if the light is well above the lower shelf. The reason for this is because the intensity of light drops off as a square of the distance, meaning that light rays at a 2 foot distance have only 1/4 the intensity that they do at one foot. Seems strange to have that kind of energy loss so quickly, but people have discovered this to be the case. One squared being just one, 2 is four but this is energy loss so you think of it as one fourth.

Cheers bud,

Turns out the reflector inside the cool tube had slipped round a bit so I think I have to agree, I've also reduced flow to co2 to the bottom shelf.

Will the bottom shelf catch up, harvest later or just be a bit stunted? Size wise they are all the same but bud development looks at least a week behind?

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Originally Posted by polishpollack

Could be co2, but it's more likely to do with your light if the light is well above the lower shelf. The reason for this is because the intensity of light drops off as a square of the distance, meaning that light rays at a 2 foot distance have only 1/4 the intensity that they do at one foot. Seems strange to have that kind of energy loss so quickly, but people have discovered this to be the case. One squared being just one, 2 is four but this is energy loss so you think of it as one fourth.

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The two shelves each have their own 600w hps and they are positioned about 14-18 inch away. I think the reflector had been kicking all the light back so the buds at the back seem more developed than those at the front.