If you are getting into home cannabis cultivation and want to work on a small (personal) scale, building a grow box instead of dedicating an entire room or purchasing a grow tent can be an effective yet affordable solution. You can build your own from simple materials, scavenged components, and a little elbow grease.
Before setting out to build your grow box, you need to consider a few factors. How much space do you want it to take up?
Mature, harvestable plants can be as short as 2 feet or as tall as your house. Plant size all depends on growing time, light intensity, and space.
As the grower, you actually control the size of the plant, so decide how big you would like them to be and plan to design a grow box to accommodate the plants, lamps, and fans.
Housing: A simple cabinet made from plywood or a sturdy carboard box (the most affordable) can serve as the grow box housing. If you want a soft-sided housing, you can build a frame out of PVC and create a tent enclosure out of mylar.
You can also get creative and transform a discarded file cabinet, dresser, an armoire, or even an old refrigerator. For small grow boxes, an old computer tower works great.
Make sure to seal all gaps in the housing with silicone caulk or duct tape. This will prevent light leaks. The floor of the grow box should provide good ventilation.
If you build it out of wood, make sure to make the floor elevated and drill some 1-inch holes in the bottom. If you are making your housing out of cardboard or other materials, create some inlet ports on the back near the bottom, but be aware that these will be a source of light leaks.
Reflector: You will need a lot of aluminum foil to line the inner surface of the grow box. Alternatively, more durable (and more expensive) reflector solutions include reflective mylar matting or sheet steel.
Grow lamps: You have many options for grow lamps and a range of prices. To go super cheap, you can use plain old ceramic fixtures mounted on a board in the ceiling of the box, fitted out with either compact fluorescents (which we don’t recommend due to the mercury in them and the risk of breakage) or compact LED bulbs.
LED strip lights also work well and produce less heat than screw-in bulbs. Mount these to a board or PVC pipe in the ceiling of the grow box.
When doing your wiring, don’t be afraid to dumpster dive and scavenge electrical cords from discarded appliances. These can easily be repurposed to provide all the wire you need; connect them up with wire nuts or generous helpings of electrical tape (safety first!).
Cooling: Cooling is all about air flow. This can be accomplished with one or two fans, depending on the size of your box.
Plan to aim the fans at the canopy if they are on a swivel base, as you find with inexpensive clip-on fans. Alternatively, you can embed a couple of computer case fans in the sides.
When using more than one fan, place them on opposite sides of the box and make your exhaust port in the top of the grow box. The fans will give better coverage and create a vortex, which will assist with air movement.
Power strip with a surge protector is an optional, but convenient accessory to make shutting things off and on easier. It is also a safety in case any electronics get wet from humidity, whereby the power strip breaker will trip and prevent any fires.
Grow medium: What is best to grow your cannabis in is a matter of opinion. Traditionally, the plants are potted to soil (pH 6.0, NPK 14:16:18), however this produces the slowest plant growth.
Some growers use a hydroponic system, which is must faster but requires a bit more maintenance. Seedlings are planted to rock wool cubes, which are then placed in 5-gallon buckets filled with clay balls and vented on the bottom and sides with holes.
These buckets are place in a water basin with a drain hose that leads to, essentially, a fish tank complete with an air pump, air stone, and a water pump. The water pump output goes to a plastic line that is fed through the bucket holes as a drip line with holes in the hose where it is placed in the buckets (just below the rock wool cubes).
This forms a circulating system that exchanges nutrients with the plant roots. Good hydroponic solutions can be purchased commercially and are optimized for different growth stages of cannabis.
Super Cheap Option: If you are really, really looking to try this out on the cheap, you can build a small grow box for as little as $60 (yup, not a typo). You will need a carboard box (free), mylar rescue blanket (rrp$1), clip-on shop lamp (rrp$10), E26 3000 lumen LED bulb (rrp$12), double-sided tape (get waterproof outdoor tape; rrp$12), duct tape (rrp$5), small clip-on fan (rrp$10), ½-inch PVC pipe a few inches longer than the longest side of your box (scavenged).
4 Easy Steps For Making Your Own DIY Grow Box For Weed
- Stand the cardboard box on its smallest side (so it is tall), apply double-sided tape with about a three-finger gap between strips to the insides of the box, and cut and lay down the mylar blanket. Cut a pipe-sized hole in the top in one corner.
- Slide the pipe through the hole and fasten to the inside of the box (either with duct tape at the bottom or use some zip ties if you have them). To this pipe, you can clamp the shop lamp at the top and the fan at the bottom.
- Cut holes to run the fan and lamp cords out. On the side opposite the fan at the top, cut a 2-inch diameter exhaust port (you can make this as a flap).
- Put your potted plants inside, close up the box and tape it shut, and plug everything in. Now you’re in business.