Using hydroponics for growing cannabis outside

Published Jul 8, 2019 09:19 a.m. ET

A lot of people are accustomed to small indoor grow rooms which are equipped to the nines with everything that you could imagine, including humidity and temperature settings, high quality grow lights, timers, and more. The idea of investing thousands of dollars for limited space is one that is no longer necessary now that growing marijuana is legal. As growers get more comfortable with the neighbors knowing that they enjoy a bit of green, many more are seeking alternative methods for growing cannabis outside that is more effective and saves space. The best outdoor grow setup will depend on how many plants you want to grow, but to start, we will assume that you are cultivating the sanctioned amount, which is four marijuana plants per household.

How much does it cost to set up hydroponics grow box?

This is going to depend on where you get all your supplies from, as much of what is needed can be salvaged from off-cut bins at lumber mills for a reduced cost. If you don’t have the patience for that, then you will probably head to your nearest Home Hardware or Home Depot. Below, you will find a breakdown of the cost that should be expected to complete your outdoor grow box.

  • 1 8-ft long x 2-ft wide x 1-inch thick wood plank = $20
  • 2 PVC caps = $3
  • 1 8-ft long x i inch thick PVC pipe = $20
  • 5 cement blocks = $20
  • 1 Rubbermaid container (reservoir) = $10
  • 1 Rubbermaid container (dry tote) = $10
  • 4 3-gallon plant pots = $8
  • 1 water filter = $50
  • 1 hose adapter (1-inch-1-inch) = $1
  • 1 piece of 1-inch rubber tubing (that will reach the grow box from the water barrel) = $5
  • 1 water barrel (with tap) = $50
  • 1 small water pump = $20

Total estimated cost: $222

How to set up a hydroponics system for growing cannabis outside

You will need

  • all the items mentioned above
  • 1 drill
  • 1 cutting tool
  • soil (or another growing medium)
  • marijuana plants (or seeds)


  1. Spread the cement blocks out evenly across an area that is eight feet long and place the large wood plank on top of them.
  2. Place the rain barrel somewhere out of the sun if possible, as colder temperatures will help to keep the ph. Levels in the water down.
  3. Use a cutting tool to remove the bottom corner from each pot that measures 2-inches x 2-inches.
  4. Set the pots on the wooden plank evenly spaced.
  5. Put one end cap onto one end of the PVC pipe, and then place it against the containers to measure where the holes will need to be in the next step.
  6. Take a drill and make 3-4 small holes located where the pots rest in the PVC pipe, to spray water onto the roots of the cannabis plants.
  7. Now you can set up the filtration system, by plugging in the filter and placing it into one of the totes that will act as the reservoir for clean water.
  8. The next step is to connect the rain barrel, and filtration chamber and PVC pipe together using the black rubber tubing and adapter.
  9. Once the watering system is in place, it’s time to prepare the pots by filling them with a growing medium, and seedlings, clones, or seeds.
  10. You may have to fill the rain barrel the first time, but nature will help to replenish the system on its own for most of the growing season.
  11. Turn the tap, filter, and pumps on, and you now have fully functional hydroponics grow box that is ready to use.
  12. Finally, you will want to use the final remaining tote to house all of your electric components, including the timer for your pump, which should be set to an hourly schedule.

The benefits of growing cannabis outside with hydroponics

  • Space saving
  • Energy efficient
  • Affordable
  • Easy to add nutrients


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