1. Place the wading pool in a flat area and lay a piece of foam sheeting on top. Use a marker to mark cutting lines and then make the cuts (figure A). This way the foam sheeting will float in the pool.2. To make the circles for the plants, use whatever you can find around the house that has a round bottom the size you need. Using a pen, mark where the holes will be in the foam (figure B). A utility knife works great for making the holes. You can put as many as 20 holes for small plants.
3. Once the holes are made, fill the pool about half full of water, then add the liquid fertilizer and check the pH level. Let the pool of water sit for a short time to warm up. Cold water directly from the hose can shock tender seedlings.
4. Since this garden will float on top of the water, you need a way to get air to the plants roots. An inexpensive aquarium air pump is just the right tool. Put the hose with an air stone (figure C) attached to the end under the water in the center of the pool. Then plug in the pump and look at all the air bubbles. They'll rise and stick to the plant roots just long enough to carry off waste before they come to the surface.
5. With the air system ready to go, lay the foam sheet on top of the water, then carefully put one herb plant in each plant hole (figure D). Make sure to tuck the roots under the water. This type of pool garden doesn't work well for very large plants like tomatoes because the roots get too large and the plants get too heavy. Larger plants also need more air circulation around their roots than the air stone provides.