Hydroponic Gardening: The Kiddie Pool Technique

Hydroponic Gardening

Indoor Gardening with Hydroponics

Hydroponic gardening is a method of growing plants without soil and is fast becoming a preferred method of indoor gardening. For those new to the world of hydroponics, the whole process may seem a bit mysterious and daunting. However, once you learn the basics, hydroponic gardening becomes rather straight forward and for many, may be the easiest way to grow their plants and vegetables, both indoors and out.

The Master Gardener program at the University of Florida has some excellent information available on hydroponic gardening. The article here, describes a simple method used to turn a kiddie pool into a floating garden.

Hydroponic Gardening: Converting A Kiddie Pool

A floating garden is easy to build and can provide a large number of nutritious vegetables. Best of all, hydroponic gardens avoid weeds and other pest problems common to soil-grown vegetables.

Materials needed:

  • Plastic children’s pool or other wide-mouthed bucket
  • 1.5 inch thick Styrofoam
  • Water to fill the pool
  • Water-soluble fertilizer, such as 20-20-20 with micronutrients
  • Epsom salts
  • Net pots or Styrofoam coffee cups with slits cut in the bottom
  • Hole saw or sharp knife


  1. Fit the Styrofoam to the pool and make sure it has sufficient room to move up and down.
  2. Fill the pool with water to a total depth of at least 5 inches.  Keep track of the total gallons of water you add.
  3. Add water-soluble fertilizer, such as 20-20-20 with micronutrients, at a rate of 2 teaspoons of fertilizer for each gallon of water used in the water garden.
  4. Add Epsom salt (magnesium sulfate) at a rate of one teaspoon for each gallon of water.
  5. Use a hole saw or sharp knife to cut holes in the Styrofoam.  A 2.5-inch hole saw is needed to drill the correct-size holes into the Styrofoam when using 3-inch net pots.  Use 1.75-inch hole saw for 2-inch net pots.  Bigger plants like Swiss chard, cucumber, and cut flowers need bigger cups to keep them anchored in the water—otherwise they fall out.  The hole size should allow the bottom of a cup to be level with the underside of the Styrofoam.  It’s very important that cups do not extend lower than 1/16 inch below the bottom of the Styrofoam sheet.  This allows the root mass to wick up water without being totally submerged.
  6. Place holes 6 inches from the sides and 12 inches apart.
  7. Place young starter transplants directly into the cups. Use toothpicks, if desired, to hold the transplant in an upright position. Do not remove the potting soil from the transplant. Do not add any potting mix or other material around the young transplant as this will keep the roots too wet and inhibit oxygen intake.
  8. Add extra water and fertilizer as needed to keep the Styrofoam sheet floating on a minimum of 5-inches of solution.

Hydroponic gardening is rising in popularity, particularly with those who use indoor gardening to grow vegetables. For a list of plants that do well with this growing method and some tips on how to care for your kiddie pool garden, read the rest of the article, here.

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Photo by Bekathwia


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