Plant food is used to help your plants grow in a healthy manner. In some cases, people feed their plants extra "food" in order to make them taller or give them bigger blooms. In other cases, plant food like fertilizers are necessary to help plants survive and ward off pests and other botanical invaders. Knowing what is in plant food and how it impacts your plants will help you purchase commercial plant food or make your own.
Main Minerals in Plant Food
There are three main minerals in plant food: nitrogen (N), phosphorous (P2O5) and potassium (K), which is frequently used in potash form (K2O) to make it more soluble. Nitrogen will "green up" a plant by promoting development of foliage and helping it grow larger and faster. Phosphorous fortifies the root systems so that the plants can withstand water shortages and draw all the nutrients that they need from the soil. Potassium will help you get bigger fruits and flowers, as well as promoting disease resistance in your plants. These minerals will be found in nearly all fertilizers, and most plants cannot get enough of them.
Organic Fertilizers and Plant Foods
Ultimately, all types of plant food serve the same end: to feed your plants and keep them healthy by providing nutrients. However, if you use organic plant food, then instead of processed minerals and time-release engineered molecules, you will have a simpler formula to get the same types of results. Most organic fertilizers are made up of fish and natural and green manures and mulches from animals and organic plant materials. If you use organic plant food, you may have to feed your plants more frequently or mix several plant foods together to make sure that your plant is "eating" a balanced diet.
Homemade Plant Food Ingredients
If you make your plant food at home, then you can tailor it to your plant's specific likes and needs. For example, egg shells steeped in water are great for plants. Many acid-loving species enjoy morning coffee watered down (or the grounds) just like you enjoy a morning roast. Epsom salts, baking powder, salt and ammonia is an effective indoor/outdoor mix.