Hydroponic gardening, also known as floating gardens, is a method of growing plants without dirt. Soil-less gardening has been around for centuries, one of the earliest examples being The Floating Gardens of China. A hydroponic garden is planted in a container with the roots growing down into water underneath, receiving oxygen from aquarium bubblers and nutrients directly in the water. A hydroponic garden can be grown in the house under artificial light, or outside.
Choosing the Container
Build or buy a container for your hydroponic garden. Dark containers are best because light can't get through. When light hits water, algae grows and this can take important nutrients out of the water from your garden. The types of containers that work well are dark plastic five-gallon buckets or dark 14-gallon square plastic storage bins. Both of these types of containers work well because they can hold large volumes of water. It is also possible to use a fish tank that has been painted black or lined with black plastic or tin foil. Whichever container you choose, the basic plans to build the hydroponic garden are similar.
Your container needs a cover to hold the planting cones and to keep the plants suspended over the water. Make a cover using the lid that came with the container by cutting four to eight circles the diameter of planting cones (also known as planting baskets). Each plant should be approximately 6 inches apart. There are companies that make lids specifically for five-gallon buckets for hydroponic gardening that includes a planting cone. If you can't find planting cones, you can make some from heavy plastic planters that are 4 inches in diameter with holes drilled around and on the bottom. To make sure the holes in the lid are the correct size, draw a circle using the planting cone as a template on the plastic lid. Cut the circle just large enough for the planting cone to fit in the lid, but not fall all the way through. Put the cones into the lid and place the lid on the container.
Fill the container with water 2 inches from the top. Just the very bottom of each planting cone should touch the water. Add 2 tsps. of a water-soluble fertilizer for each gallon of water. Add 1 tsp. of Epsom salt per gallon of water.
Fill each small planting cone half way full with gravel, such as expanded shale, hydroton, perlite, vermiculite or rockwool. You can find these types of gravel at plant and garden centers.
Purchase three air stones, plastic tubing and an aquarium air pump at a pet supply store. Attach the plastic tubing to the three air stones and put them into the bottom of the container under the water. Air stones are also known as bubblers, which attach to an aquarium air pump. Attach the pump to the stones via three plastic tubes and place the pump on the outside of the container. Plug the air pump into an electrical outlet to make certain it is making the air stones bubble up oxygen to the surface. The oxygen is needed for the roots of the plants or they will suffocate.
Plant your small plants into each planting cone. Gently rinse the dirt off the plant roots and place the plants in the gravel planting cones.