Just like all living things, fruit trees require food to grow. Plant food typically gives your fruit tree a variety of nutrients, including nitrogen, potassium and phosphate. In order for your fruit tree to grow healthy, it is important that it have adequate amounts of all three nutrients, as each benefits the plants in certain ways.
Compost is a natural, organic way to feed fruit trees. Compost is simply organic waste matter, such as fruit and vegetable peels, that is broken down into simpler substances by worms or insects. This Old House suggests using compost as a fertiliser for fruit trees because it contains a low amount of nitrogen, which is typically perfect for feeding fruit trees. Many commercial plant fertilisers contain a higher amount of nitrogen, which can result in lots of flowers on the tree, but not much fruit.
Horse and Chicken Manure
Like compost, horse and chicken manure make good fertiliser because they contain the appropriate amounts of nitrogen needed to produce healthy, high-quality fruit on the trees. Manure also works well because it releases its nutrients slowly, providing food for the trees for a few months. Manure should be placed around the base of fruit trees in the fall and winter, before the trees go into dormancy and can't absorb the nutrients.
Liquid Plant Food
Liquid plant food is advantageous for fruit trees as long as it contains the appropriate amount of nutrients. Fertiliser typically contains three numbers on the packaging. These numbers refer to the levels of nitrogen, phosphorus and potassium, in that order. Many fertilisers contain 4-1-1 ratios; however, this amount of nitrogen is typically too high for plants. Instead, opt for a 1-1-1 or 1-2-1 ratio. In addition, look for food that is either half-water soluble or slow release and half-water soluble. Slow-release fertiliser will provide your fruit tree with food for a few months.