Build a Floating Hydroponic Garden

Building a Floating Hydroponic Garden

Building a floating hydroponic garden, also known as the Raft system, provides an advantage to gardeners because its plants are normally free from pests and would be able to produce as the plant grows using the traditional method. It is also ideal for planting leafy green plants such as lettuce, kale and mustard greens, and herbs such as basil, mint and watercress.

What you need:

  1. 2-by-6 inch lumber
  2. 6-mm plastic sheeting
  3. 1-by-2 inch lattice strips
  4. Wood screws
  5. 1 ½-inch-thick Styrofoam sheet, approx. 4-by-8 foot area
  6. Water
  7. Water-soluble fertilizer
  8. Hydroponic nutrient solution
  9. Epsom salts
  10. 1 ¾-inch hole saw or sharp knife
  11. Drill
  12. 2-inch net pots
  13. Transplant plants


  1. First of all, you need to select a suitable location for your floating hydroponic garden where you should take into consideration the light and shade requirements of your plants. Then, build a rectangular frame by cutting two pieces of 2-by-6 inch lumber 4 feet long and two pieces 8 feet long before securing the frames together using wood screws into a rectangular box.
  2. Then, you need to spread 6-mm of plastic sheeting over the wood frame and across the open expanse of the frame. After that, you have to press the sheeting down along the side of the wood frame before securing. This is to create the plastic sheeting as the bottom of the floating garden. Next, secure it to the frame using 1-by-2 inch lattice strips and wood screws along one of the edge of your wooden frame.
  3. After that, cut the 1 ½ inch Styrofoam sheets to fit inside of the wood frame for covering the surface of the plastic sheeting and ensure that the Styrofoam is loose enough inside the frame enabling it to move easily.
  4. Then, you have to fill the floating garden with approximately 20 gallons of water until it reaches the depth of 4 inches. Monitor the number of gallons added especially when you add the fertilizer. After you have finished filling the garden, attach the plastic sheeting along the other sides of your wooden frame using 1-by-2 inch lattice strips and wood screws.
  5. For every gallon of water that you add, you need to also add 2 tablespoons of 20-20-20 water-soluble fertilizer and 1 tablespoon of Epsom salts.
  6. Next, cut 1 3/4-inch holes in the Styrofoam using the hole saw and position it 6 inches from the side and 12 inches from the next hole.
  7. Take your 2-inch net pots and cut the bottom of the pots before placing them into each of the Styrofoam hole. Ensure that the bottom of the pot does not extend more than 1/8 inch past the bottom of the Styrofoam so that the plants do not receive too much water.
  8. Finally, position your starter plants directly into your net pots and do not remove the potting soil on the roots of the transplant. If necessary, add some more water in order to keep the sheet of Styrofoam to always float on 4 inches of water.

Image Credit:

Additional Reading:

How-To Hydroponics, Fourth Edition

Hydroponics: Indoor Horticulture