Greenhouse Hydroponics: How to Build Your Own Inexpensive System
Hydroponics is defined by the Merriam-Webster dictionary as “the growing of plants in nutrient solutions with or without an inert medium to provide mechanical support”.
My experiences with hydroponics began twelve years ago, when I used styrofoam stackable planters to grow strawberry plants vertically in confined spaces.
The growth media used in these vertical planters was vermiculite, and the nutrient solution was delivered to the top of the planter, which then drained downward and ultimately out the bottom of the planter onto the ground. However, the wind often blew media away.
I needed a recirculating hydroponic system to grow vegetables on my patio or in my hobby greenhouse.
I did not want to spend hundreds of dollars on a manufactured hydroponic system, so I did some research on how to build my own. I came up with a simple design that works: Easy to assemble, disassemble and to clean. This system is scalable, from one pail to many pails: My hydroponic system uses five gallon pails that can be purchased from any local home improvement store. A reservoir pump runs nutrient solution through a hose over the pails. Drippers control the flow to each pail, and the solution runs through the perlite media in each pail and then drains out of the pail back into the reservoir.
This article explains how to build a three-pail recirculating hydroponic system. To build a larger one-line system, you may use a higher capacity pump and reservoir as well as longer irrigation and drain lines. For example, in my hobby greenhouse, I use a 55 gallon Rubbermaid Brute brand garbage can reservoir for an 8 pail recirculating hydroponic system.
A recirculating hydroponic system requires replacement of the nutrient solution in the reservoir every few weeks to avoid nutrient imbalances. I pump out the solution in the reservoir using a ¼ horsepower basement sump pump connected to a garden hose onto plants in my backyard.
Over the years, I have tried vermiculite, perlite and hydroton growing media in the pails. Each has its merits, but perlite is my preferred choice, since it promotes the best root growth in the pails. I purchase coarse perlite in bulk bags from a local retail greenhouse business. Paint strainer bags in each pail contain the perlite and prevent it from traveling into the reservoir and plugging the water pump intakes and hosing.
Most components of the system can be purchased from your local home improvement store. Some components, such as the pump, hosing, and drip emitters, can be ordered online.
Parts Needed for This Project
- 3 – Five gallon pails (dark color to prevent light transmission and algae growth)
- 3 – 6 inch Wide Lip Bucket Basket – Round Plant Container with Mesh Bottom
- 6 – ¾ inch diameter PVC elbow joints
- 1 – 2 inch diameter PVC pipe (cut length to size to fit)
- 1 – ¾ inch diameter PVC pipe (5 foot length)
- 1 – 2 inch diameter PVC end cap
- 1 – Water pump (usually comes with ½ inch hose adapter)
- 1 – 10 feet of ½ inch diameter poly tubing (buy it in a roll and cut a length to use)
- 1 – 5 feet of ¼ inch diameter poly or rubber tubing (buy it in a roll and cut lengths to use)
- 1 – Enough coarse perlite to fill 3 five gallon pails
- 1 – Reservoir (large enough capacity to accommodate all the pails in your system) w/ lid
- 3 – Paint strainers for five gallon pails
- 1 – End cap to fit on the end of the ½-inch diameter poly tubing
- 3 – Pressure compensating drippers (4 gph)
- 1 – Bag of UV-resistant zip ties (different lengths)
- 3 – Four inch support stakes for ¼ inch tubing
- 1 – Timer (to turn water pump on/off)
Tools Need for This Project
Tape measure, battery-operated drill, silicone caulk, magic marker, PVC pipe cutter, 1-inch diameter drill bit, 1-1/8 inch diameter drill bit, 2-½ inch diameter drill bit, punch for making holes in poly tubing.
To reduce the heat build-up on the root systems in the pails and/or to prevent algae growth by reducing light transmission, you may want to wrap each pail in reflectix and secure each section of reflectix using metallic foil adhesive tape.
Although you do not need a table or bench, it does make maintenance and cleaning easier. No matter how you support this hydroponic system, you need to give the 2-inch diameter return pipe a tilt to allow drainage of the nutrient solution back into the reservoir from the pails. I do not use PVC cement to attach PVC parts together: This allows for disassembly and cleaning.
- Cut the 2-inch diameter PVC pipe down to the length of the bench leaving room for the PVC end cap and the length of pipe that enters the reservoir.
- Place the pails on the bench and decide upon the spacing between them that is relative to the 2-inch diameter PVC pipe’s location. Remove the metal carry handles from the pails.
- Mark the placement of the drain holes on the side of each pail five inches above the base. (Depending upon the height of the 2-inch diameter PVC pipe in relation to the pails’ positions, your pails’ holes will be higher or lower than what is described in this article).
- With a drill and the 1-inch diameter drill bit, drill out holes on the marks on the pails.
- Cut six 3-inch and three 12-inch long pieces of ¾ inch diameter PVC pipe. (Your lengths will vary depending upon the distance of the pail from the 2-inch diameter PVC pipe: In this article, the 2-inch diameter PVC pipe lies on the bench seven inches from the pails.)
- Insert the 12-inch piece of ¾-inch diameter PVC pipe into the pail side hole until the pipe end reaches the center of the pail. It will be a very tight fit. Insert a ¾-inch diameter PVC elbow joint onto each end of this pipe, followed by inserting a 2-inch piece of ¾-inch diameter PVC pipe into each elbow joint, and then turn the entire assembly downwards (like an upside-down U) in each of the pails. There should be roughly a one-inch or less gap between the PVC pipe assembly’s end and the bottom of the pail.
- Use silicone caulk to run a bead around the circumference of the entry point of the ¾-inch diameter PVC pipe outside of each pail. Do not move the pails until the silicone cures.
- Mark the placement of holes on the top of the 2-inch diameter PVC pipe that correspond to the location of the PVC pipe extending from each pail.
- With a drill and the 1-1/8 inch diameter drill bit, drill out holes on the marks on the top of the 2-inch diameter PVC pipe. Empty out the shavings in the pipe.
- Insert the 2-inch diameter PVC cap onto the end of the 2-inch diameter PVC pipe facing away from the reservoir.
- Insert the other end of the 2-inch diameter PVC pipe into a hole cut into the side of the reservoir (as far up the side as possible) and attach the optional 2-inch diameter PVC elbow to the pipe inside the reservoir.
- Place the water pump at the bottom of the reservoir after securing the end of the ½-inch diameter poly tubing to the adapter on the top of the pump. Run the poly tubing and the electrical cord from the water pump up and out of the reservoir via a second hole cut into the uppermost side of the reservoir (or you may choose to run these through a hole cut into the reservoir cover/lid).
- Insert the end of the ¾-inch diameter PVC pipe assembly projecting from each pail into a hole in the top of the 2-inch diameter PVC pipe.
- Run the ½-inch diameter poly tubing along the length of the pails and use zip ties to secure the tubing to the holes left from removing the pail handles.
- At the end of the length of the ½-inch diameter poly tubing (opposite the reservoir), insert/secure the end cap.
- Using the punch, make a hole in the ½-inch diameter poly tubing next to each pail and insert a pressure compensating dripper. It should be a very tight fit to prevent leaks.
- Cut a length of ¼-inch diameter poly or rubber tubing to size and insert one end of the tubing into the dripper end for each pail location.
- Insert one paint strainer into each pail and fill it with coarse perlite.
- Insert the Wide Lip Bucket Basket lid onto each pail and fill the mesh pot with perlite.
- Secure the other end of the ¼-inch diameter tubing over the surface of the perlite using a support stake for each pail.
- Fill the reservoir with nutrient solution: I recommend that beginners use the Flora Nova Grow (7-4-10) product from General Hydroponics. Connect the water pump to the timer.
- Test out the hydroponic system and make sure that each drip emitter is functioning, and no leaks appear.
- Plant your crops in the perlite in each pail’s lid net pot: I usually grow tomatoes, peppers, and cucumbers in my hydroponic system.
Mark’s interest in horticulture began at age 13, when he grew a banana tree from a corm that he purchased from a Gurney Seed and Nursery catalog. He has been “bananas” about gardening and greenhouse growing ever since. Visit his blog at http://greenhouseadventures.weebly.com.
Read more articles:
Common Mistakes When Using Beneficial Bacteria in Hydroponics
Growing Fruit Using Hydroponics
Growing Wheatgrass with Hydroponics vs Soil
Hydroponics System Daily Maintenance Check List
Understanding Sphagnum Moss for Hydroponics
Using Molasses in Hydroponics