Phostrogen® All Purpose Plant Food is suitable for use on all garden plants including edible crops, fruit trees, lawns, young plants, seedlings and even houseplants. Phostrogen® All Purpose Plant Food provides the perfect balance of nutrients containing a number of vital nutrients such as Iron (Fe) and Magnesium (Mg) in addition to Nitrogen, Phosphorus and Potassium (NPK). Phostrogen® and has been helping gardeners achieve fantastic results for over 50 years. 400g