Pssst. Do you want an at-home covert cannabis grow? Do you want to build a secret grow cabinet to house your at-home operation indoors? Need to do it on a tight budget? Over just a few hours? With little to no outside help? No worries! With these instructions and a budget of under $200 USD, anyone can design and construct a cabinet that will grow happy, healthy, potent cannabis plants, from clone through flower.
In a previous story about growing cannabis with children in the house, we discussed starting and maintaining a small, personal-use grow in an illegal state. Not only will cultivating a secret garden by way of a self-designed and constructed cabinet be the perfect in-house solution for any type of plant, but should you choose to place the cabinet in your kitchen like I did, it’s likely to add three feet of functional counter space. Bonus!
This particular grow box was designed to be affordable, simple to assemble, and simple to disassemble if you currently reside in an illegal state and wish to relocate to a more grow-friendly area.
Planning Your Grow Box
Success begins with the planning phase, as careful consideration of the process and materials to use will help ensure a smoother, easier project, from start to finish. We suggest commencing this project by utilizing a straightforward software program for computer-aided design (CAD). SketchUp Pro 2014 will help you to create a personalized design and carefully measure each cut of lumber. While SketchUp offers up a free trial of its program and previously had a version that was free to use, the current full price of the downloadable software is $695 USD.
Although that price may seem prohibitive to some, with a variety of templates and handy tools to choose from, SketchUp is a useful investment for the DIY-er who is attempting design for the first time.
If you would rather not pay a premium for a CAD program, there are free alternatives to be found on Google, such as LibreCad, which should sort you out.
Tools You’ll Need To Build Your Grow Cabinet
- Staple gun for the reflective material
- Wire cutters for the chains
- Duct tape to seal the doors and edges
- Cordless drill
Materials And Cost Of Building Your Grow Cabinet
- 8 2x4x8 common building studs, cut to fit: Lowe’s $3.26 each
- 7 pieces of industrial particle board, cut to fit: Lowe’s, $7.81 each
- 3-inch wood screws: Lowe’s, 240 for $25.24
- 20 feet of 1-inch steel chain: Lowe’s, 0.68 cents per foot
- 4 small cup hooks: Amazon, $1.86 for pack of 50
- 2 hinges: Lowe’s, $2.78
- Self-closing flush cabinet hinge: Lowe’s, $2.80
- Lock: Lowe’s, $3.98
- 2 15-foot extension cords: Amazon, $9.97 each
- Small fan (free, obtained from an old desktop computer)
- Tarp (free, had one laying around the yard)
- Mylar Blankets: Live Action Safety, 0.99 cents each
- 8 compact fluorescent (CFL) bulbs: Amazon, $15.08 for pack of 4
- 4 dual-bulb adapters: Home Depot, $2.48 each
- Digital thermostat/humidity gauge: Amazon, $9.40
- Timer: Lowe’s, $4.98
Total Cost: $191.32
How To Build Your Grow Cabinet
Step 1: Once you finalize the design and procure the materials, start the build by framing the cabinet using the cut 2×4’s with 3-inch wood screws.
Step 2: Create a basic frame measuring about 44 inches long, 36 inches tall, and 24 inches deep.
Step 3: Cut to fit common building studs for the frame and industrial particle board for the floor, sides, top and doors (the staff at Lowe’s were very accommodating, considering I asked them to cut every piece of lumber for free).
The following chart gives the exact measurements of each 2x4x8 stud and how many were used in this project. Altogether, a total of eight were purchased (this accounts for extras, in case you mess something up), and seven pieces of industrial particle board.
Step 4: Using the particle boards, place the floor, sides, back and top to the frame, securing with the wood screws.
Step 5: Next, it’s time to install the small electric fan to aid airflow, which can be repurposed from an old desktop computer. Start by cutting a 6×6-inch square hole for the fan in the upper-right portion of the cabinet. Then, cut a horizontal 1-inch slot 4 inches from the bottom of the particle board on the left side of the cabinet, to serve as a passive ventilation system. The cabinet’s fan and lighting system will be powered with an extension cord.
Step 6: All cannabis growers come to appreciate how critical lighting is for healthy and happy plants. For this secret garden, I chose to create a simple CFL lighting system for several reasons:
- Affordability: At the time of this build, CFL bulbs were more affordable than LEDs, although the market appears to be phasing them out now.
- Long lasting: CFL bulbs use a fifth to a third of the electricity compared to incandescent bulbs, and last up to 15 times longer.
- Easy to obtain: Could be ordered online or at any decent hardware store.
- Not an obvious grow item: Should not raise suspicion if delivered to your home.
- Suitable for small grows: The bulbs are small enough to fit into any tight space and are easy to replace.
- Do not overheat: Safety is an important factor when considering a secret grow, and these bulbs minimize the risk of a fire in an enclosed space.
On average, one plant per bulb could expect to yield approximately three-quarters of a pound to one pound of flower, given appropriate vegetative and flower time, and the strain you’re growing, of course.
The lighting is designed to work with all life stages of a cannabis plant, in that the bulbs can be easily changed from daylight spectrum for cloning and vegetation, then to soft white when flipping for flower. I added dual bulb adapters to allow two bulbs per socket. No fancy, overly complicated wiring was utilized; just a basic extension cord, which was cut and wired to the bulb adapters.
Step 7: The frame for the lighting was also designed to be easily adjustable by one person, by way of 1-inch stainless steel chains and a series of bungees cords. Twenty feet of lightweight steel chain can be easily cut to fit to a hook on each edge of the frame.
Step 8: Two doors to seal out air and light can be added to the frame. Use two hinges that measure 1.5 inches and a two-piece, self-closing flush cabinet hinge, which locks with key-locking master lock.
Step 9: Inside the cabinet, double up a large waterproof tarp and staple it securely to the floor and bottom of the walls to prevent rot from water runoff. I found a remarkable deal at a local grocery store on silver Mylar emergency thermal blankets for .99 cents each, which I cut to fit and stapled to the sides, doors and ceiling to help with heat from the reflection. The material was easy to use and worked very well, and two 52-inch x 84-inch blankets were sufficient to cover the inside of the cabinet.
Step 10: A timer for the lights and a thermometer (with humidity gauge) were also necessary yet affordable items. Temperature and humidity are important elements to monitor in any grow, so don’t leave it to guessing. Anything above 80 degrees Fahrenheit is simply too much for a small grow inside an enclosed cabinet.
What To Expect Once Your Cannabis Grow Cabinet Is Up And Running
At full production, I was able to fit a cloning station (which had a watertight base tray measuring 11 x 22 inches, a 7-inch dome, and a heating mat with 72-cell seedling inserts); six mature vegging plants that had been subjected to low stress training (in 2-gallon fabric grow bags); and numerous Solo cups for when the plants had rooted from cloning.
Once the plants were switched to bloom phase, I had the option of either changing the bulbs in the cabinet and flipping all the plants to bloom at once, or creating a separate space for flower. I chose the latter by converting a bedroom closet with a basic 400-watt digital ballast setup, for $219.99. (This additional cost is not figured into the cost of the grow cabinet itself and should be considered when at the initial planning stages.)
While growing my first crop in my DIY grow cabinet, I swiftly and deftly learned to deal with the dreaded fungus gnat invasion. Any water that accumulates, as well as the soil of any plants, can be an invitation for a number of pests, and fungus gnats were the bane of my existence — until I discovered a very cheap, organic and useful method of elimination.
Pour a small amount of apple-cider vinegar in a shallow bowl and add 3–4 drops of dishwashing liquid. Set several around the area, paying special care to refill every few days. The gnats are attracted to the sugar in the vinegar and will die when they ingest the soap. No spraying required, and not attractive to pets or kids. I found this a useful tip, which I utilized several times during my secret grow.
We hope you find this guide to building your own at-home grow box useful and encouraging. Fill your cabinet with happy plants and enjoy the incredible botanical learning experience.