Plants need air, light, soil and water. Derek Garden Centre can test existing soil and water supplies to make sure that the plants are living in a healthy environment. Samples of soil and water are taken to local laboratories and meticulously tested. Soil content is tested for acid and alkaline particles which effect the growth of plants. Supplements are then used to enhance the quality of the soil. Water is tested for its salt conductivity. Fertilizers are then recommended based on the results of soil and water supply in the garden.