Okay you don't have time to look stuff up sit back and I will do it for you. Get ready for some info.
A humidity and temperature gauge are essential in any growroom. Daytime conditions should be 70-80 degrees without co2, 80-90 degrees with co2 until the last two weeks when daytime temps should be kept between 70-80 and co2 can be reduced to adjust for the lower metabolism. Night temperatures should be kept above 60 degrees to prevent stress. It is preferrable during flowering to have a night temperature drop of 10-20 degrees to stimulate flowering hormones and reduce stem elongation.
I find that low humidity causes stress on plants. I recommend 50-60% humidity until the final 2 weeks of flowering. At this point, the humidity should be lowered as much as possible to encourage the plant to seal and protect itself with additional resin. (I am able to get the humidity to go as low as 31%) I have been able to frost things up considerably this way. The higher humidity levels prior to final ripening reduce salt levels within the plant tissue and encourage healthy, more lush growth.
How do I add ventilation to my grow area?
There are a couple of considerations to observe when planning your ventilation, they’re pretty simple concepts; but they are often overlooked.
· First, remember that warmer air will naturally rise to the top of any container, and that cooler air will naturally settle towards the bottom.
· Also remember that when ventilating any space, the volume (VOLUME, in cubic feet or cubic meters... [L x W x H]) of air that goes IN, also has to come OUT.
· You can’t expect to ventilate a grow space by simply forcing air in, and not providing an exhaust vent.
Since the object is to remove as much warm air as possible, and replace it with cooler air, it will be most efficient to place the exhaust as close to the top of the space as possible, and place the intake as close to the bottom as possible.
Should I place the fan in the exhaust, intake or both?
The fan should be placed in the exhaust, and the intake should be a simple hole (or light trap, if light getting out is a concern).
This type of system is known as an Active Exhaust, Passive Intake System.
Mounting the fan in the exhaust, sucking air out of the room accomplishes a couple of things...
· Since the exhaust is at the top of the area, the fan will suck the hottest air out of the area first.
· The fan is actually lowering the air pressure inside the area. Any incidental pinholes or leaky seams will simply draw air in. If the fan were blowing IN, those pinholes and leaks would allow potentially smelly air OUT.
How big should the passive intake be?
It should be slightly larger than the exhaust. Remember, the volume of air being blown out, will be replaced through the intake. Using a bigger intake hole allows the incoming air to be at a lower velocity (speed), which minimizes mixing up of the air in the area. It will also allow the fan to operate more efficiently.
How big should the fan be?
Fans are rated in either cubic feet (CFM) or cubic meters per minute in North America. In Eurpose, metric fans are rated in m3/hr - cubic metres per hour (m3/hr).
That means a 70CFM fan will move 70 cubic feet of air in one minute.
Your fan should be big enough to move the volume of your area 2 to 3 times every minute. A 70 CFM fan would be adequate for a 35 cubic foot area, and would be optimal for roughly a 23 cubic foot area.
· To figure your area’s cubic volume, multiply (in feet) the length by the width by the height.
What if I have more than one fan? Should I use one to blow air in and one to suck air out?
Not if the object is to provide as much ventilation and cooling as possible.
· If you have two 3-inch diameter fans, and you mount one in the intake, and one in the exhaust, you have a total intake area of one 3-inch hole and a total exhaust area of one 3-inch hole.
· If you use both fans as exhausts, you have TWO 3-inch exhausts and two 3-inch intakes (actually, two 3.3 inch intakes. They should be bigger than the exhausts, remember?).
· Twice as many holes, twice as much airflow.
A very general rule of thumb is that your garden needs 50 watts of HID lighting per square foot of illuminated area. This rule ignores the shape of your garden, so the following is really a better guide:
A 250 watt HID will illuminate a 2' x 2' garden.
A 400 watt HID will illuminate a 3' x 3' garden.
A 600 watt HID will illuminate a 3.5' x 3.5' garden.
A 1000 watt HID will illuminate a 4' x 4' garden.
The amount of time your garden should be exposed to lighting depends on what 'cycle' your garden is in:
The 'Vegetative Cycle' of your garden starts with the sprout of the seedlings and can be continued indefinitely. In the veg cycle your garden will require a minimum of 16-18 hours of light and 6-8 hours of darkness daily. Since a given amount of light can only do so much, equal production can be realized in a smaller space with less plants, where the light is concentrated and the plants can grow more efficiently. Using more light helps additional co2 uptake.
Since a plant can be kept in the 'Veg cycle' indefinately, many growers cultivate 'Mother' plants. This plant is used for clone starts and never produces buds, only new growth.
The 'Flower Cycle' or 'Bud cycle' is typically equal amounts of light and dark, 12 hours on, 12 hours off or 12/12. This produces a change in the plants metabolism simulating Fall, shorter days....less light.
This is the cycle that the plants will show their sex. Usually, you'll be able to determine the sex within the first 2 weeks of 12/12. By the 3rd week most plants have developed healthy bud sites or pollen sacks.
The plants will continue on the 12/12 cycle until harvest.
When someone
'Re-vegges' a plant that has been in the flower cycle, they're switching the light cycle back to 18/6 to stimulate new vegetative growth.
