The Grow Box for Cannabis
A closed weed grow box system will enable you to create and
control your own growing environment such as the sun, rain, wind, air,
nutrients and pest control. Here are plans for a 64 cubic foot box.
The grow box material list is: Three 4 foot x8 foot sheets of
half inch plywood or OSB board. cut in half to get six - 4 foot x 4 foot
pieces Six pieces of 2x2 - 8 foot long lumber 8 feet of 1x2 lumber and 8
feet of small molding a pound of thin wood screws, 1.5 inches long white
glue other items depending upon design (fans, glass, lighting)
The weed grow box tools required are: power saw drill and bits
misc. hand tools
Here are a few items to remember for your grow box:
Check the grow box plans over first before starting. Lumber sizes are nominal
dimensions. ie: 2x2 lumber actual size is 1.5 inches x 1.5 inches
Measure twice and cut once!
- If using an HID (Hi Intensity Discharge) light,
choose a universal position bulb. Double check the airflow direction
of the fans.
- Always use protective eye ware. Don't take your
sight for granted.
- Make sure the light ballast keeps cool. Use a
small fan if necessary.
- You need to determine which type of lighting and
venting to use.
Open style weed grow box uses the light in the same area as
the growing space. This requires a vent hole in the top near the light
and one in the side of the box. This is the simplest, with all air
vented to a single outlet. Extra care is required to ensure the plants
don't grow grow too close to the bulb. They usually know when it's too hot
and turn away.
Enclosed style grow box uses a single pane of glass to
separate the light from the grow space. This allows the separate venting
of the bulb heat from box odors, reducing wasted heat for cool weather
operating. If you plan to use an HID bulb, then this requires three
holes in the top. Use the hole in the center (see diagrams) for the
light vent exit, another for light vent intake, and a third for the grow box
If you plan to use hydroponics or sprinklers, then
you have to use the enclosed system to protect the bulb from water. For
fluorescent lighting, it is simpler to use the open style because of the
low heat created.
When wiring equipment, make sure all connections are
secure and no live wire exposed. Even a small gap will attract your
finger or water and cause a problem. Proper twist-on connectors work the
A quality computer style fan works best for venting.
To make it simple, find a fan with 120/220 volt AC input. Try to find
one with the most power (about 20 - 40 watts) and rated air flow (150
CFM's minimum). The squirrel cage style fan can provide more airflow if
required. These may be rated the same CFM's, but have more power to vent
out a long pipe. Try to plan the vent holes around the fans you are
using. You can always modify the box with a new hole and patch an old
Have the grow box vent fan drawing air out the the box,
and the light fan pushing cold air into it's area. This will ensure that
no box odors escape other than the grow box vent.
Build two of these for the sides of the box. Glue the 2x2 lumber into
place and place screws in from the plywood side.
Then make two pieces for the top and bottom:
For the front and back, trim the 4x4 plywood:
Next, stand up the sides and place the top piece on.
Once you are sure it fits, use screws to fasten together. Don't use glue
here, in case you want to disassemble it later.
Turn the box over, and attach the other side the same
Attach the back piece in place, and check the door
for proper clearance. You can use hinges for the door, or simply a small
dead bolt in each corner.
There are many manufactures and sizes of HID bulbs.
To create the closed system, you have to custom make the frame to
enclose the HID bulb you are using.
Build the frame to support the glass.
Seal the inside joints of the weed grow box with silicone
sealant, and use weather stripping for the door. You can either use
white paint or poly for the inside of the box. This gives you the best
coverage of light everywhere. For hydroponics and sprinklers, poly will
easily protect the wood and save you some trouble. You can also seal the
base to contain the nutrient solution.
This next picture shows a well used hydroponic
system. It consists of the poly liner, garden hose main line and the
individual watering hoses. A submersible pump sits in the solution, with
the return line filtered over the pump. The main line is secured with
staples and strips from plastic drinking bottles.
The air intake for the sealed base comes from the
space before the door. Use a spacer to keep the poly from pushing out an
The plants are in potters, secured in a tub with a
bottom drain. The roots will cover the bottom of the tub, but stay away
from the pump. Any large sediment will plug the individual watering
You can also use the light at the back of the grow box.
This uses only a single pane of glass. The fan behind the bulb draws air
in, and exits to the left. The fan at the top is the grow box vent exit.
This shows a typical corner with the plywood, 2x2
lumber, dead bolt latch, weather stripping and caulking.
The extra piece of plywood was used to modify the
opening size of the vent out.
Use a fine screen or filter for the air vent intake
on the side. This keeps out unwanted bugs, varmints etc.