Since the amount of light doesn’t matter, but being it’s beneficial allowing them time to cycle thru their droop and perk back up in the dark, would setting the lights to come on shortly after they reperk up be the optimum setting even if it was 19:5 or even 21:3 to max out light usage?
These are my 11wk old Moby Dicks. Getting close!
Lookin great @Darkstar528 ! 
It gets real exciting from here. We’ll be your support group here in the next few weeks to talk you out of chopping them down yet. 
I wouldn’t fuss with the light schedule too much at this point. Just keep on doing what you’re doing and ripening those buds!
you can run autos 24/7 as growth is based on hormones, not light. More light = more growth. Many of us let our plants “REST” a little. I run 20/4 on autos with great results. The extra light did not produce enough extra growth to warrant the cost of the extra expenses of power, heat, humidity control, etc. Just was not a good ROI after 20 hrs. When I have explosive growth, I even go back to 18 hrs. That extra has not been worth the cost of achieving it. My 18hr harvest is within 10% of 24hr harvests and the cost eliminates / negates the productivity…for me. Every environment is different so base it on yours
How are you saving on heart/humidity going dark for 4 hours? You growing in a tent/closet/room?
yes, tent / closet or any environment where you can have positive or negative ventilation. I save on the electric by having lights off, transpiration slows down so humidifying / de-humidifying somewhat stalls, less light means less heat means less cooling required, lower Rh (depending o the room / outer environment of a closed system)
Closet that is 2x3 feet.
Lots of the trichomes seem to have lost their bubble heads. Is that normal?
?? positive or negative ventilation - please explain. I have a room 7.5 x 10. I can pull air in from another room and expel to that other room. Or I can run self contained (recirculate). Some fresh air can come in from the attic area above the room paneling that has a screened opening. I’m just getting set up so I need to do testing once lights are in.
@GrnyGrows Positive pressure - you are pulling air into your room, more than is escaping.
Negative pressure - you are sucking the (filtered) air out of the room, more than what can freely flow in.
With positive pressure, air from your room (or tent, in my case), can leak out unfiltered into other rooms, as there is more air in the room than it would normally hold with no ventilation. Not good if you are trying to control smell.
With negative pressure, you force the nice odiferous air out thru the filter and let air come in from outside…stinky air cannot escape as air is being drawn in, only way out is thru your filter.
With my tent on negative pressure, my 4x4 went down to about a 3’6"x3’6" tent as it sucked the sides in! Easy fix, get some 4’ bamboo and place horizontally between the corners of the tent at 1/3 and 2/3 tent height. Then it only sucked in about 2" on each side, but not where my plants are their widest (I don’t mind loosing 2’ at bucket level or near light level, but 6" right in the middle of the tent…no way!).
In a room like yours, go for smell control, negative pressure is what I’d use.
Hope this makes scents!
what if I’m using a filter in and filter out? You’re really helping me. Thanks so much.
With filtering in and out airflow, I would have it blow out more air than sucking in, so negative pressure. Set intake to 5 and outflow to 6 or something like that. Then those lovely pleasant aromas won’t escape and freak the neighbours out!
Unless you WANT to make them envious!
I agree wholeheartedly. Buy those simple controllers and you can raise / lower the flow with the touch of a dial
Vivosun and BN Link offer very good devices at under $20
@GrnyGrows not sure why you would want to filter the input and output. Bring in fresh air that is somewhat controlled from somewhere, the attic is probably not the best because in winter it could get really cold and in the summer really hot and now you have to deal with those temps in your room somehow. Exhausting to your attic is a good idea. I would not concern yourself with pressures you want air coming in and air going out…I am assuming you will use the whole room and not install tents in this room. I see a 6 inch fan and filter, and if you have several lights you might need another to keep that heat out of there and keep air moving to bring in CO2. You may want to get a 8 inch system to help but see if the 6 works first…
What kind of weather you live @GrnyGrows east coast west coast or in the middle northern southern
We have a shed/barn. We’re pulling into the grow room from the main part of the barn and exhausting out into the main room. We’re doing this to control temperature and humidity throughout the 12x20 structure. If we pull air from outside, most of the time its incredibly hot outside. I’m thinking the full length vent in the top of the building will bring in enough fresh air as we pull in from the main room. Think I need to change the exhaust to go out the roof. Worried about smell.
We have two of the large fan/filters. I am worried about my CO2 levels though. We’ll be testing at the end of the week without plants to see what we get.
@GrnyGrows if your charcoal filter is good there will be no smell on the exhaust. I run 2 tents in a bedroom that exhaust into that same room thru charcoal filters and there is no smell anywhere in the house.
Excellent. This is what I was hoping you would say. How do you get your fresh air? Sorry for all the questions I’m just being super careful before my first grow. You’re awesome.
How I can be sure to have enough in the room. If I’m recirculating my air throughout my “barn” will there be enough CO2?
