The nitrogen in ammonia makes many people think that it can be used as fertilizer and promote plant growth. However, using household ammonia, found in many cleaners, can do more harm than good. Knowing the ins and outs of this chemical and its effects on plant growth might make you think twice before using it. Ammonia and plants Ammonia is present in soil, water and air and is an important source of nitrogen for plants. Nitrogen promotes plant growth and improves fruit and seed production, resulting in greater yield. It is also essential for photosynthesis, the process by which plants convert light energy into chemical energy. The ammonia found in many household cleaners is diluted in water and contains ammonia and ammonium and hydroxide ions. Although ammonium ions are effective as a fertilizer, it is the aqueous ammonia that is toxic and can wreak havoc on seedlings. (See References 1 and References 2, p. 25) Ammonia and Soil pHSoil pH, which can vary between 0 and 14, determines the availability of nutrients in the soil. A pH below 7 means...