Olive trees are flowering plants native to Middle Eastern Europe, especially around the Mediterranean Basin. They are often grown for their popular olive fruit, which is usually harvested during the fall. Olive trees must be fertilized properly to provide enough nutrients to form the fruit and to stay healthy and pest free.
Young olive trees may require fertilizing after planting, depending on the time of year. Do not immediately fertilize trees planted between late October and early March. Put off the first fertilization until mid-March, as the tree will not need the food during its winter dormancy period.
Spread a thin layer of mulch over soil surrounding the tree after planting. Leave 2 to 3 inches between the mulch and the trunk of the tree. Do not use wood chips or cellulose mulch. They have high carbon content and will drain nitrogen from the soil as they decay. Pine straw is the recommended mulch for olive trees, as it contains low amounts of carbon and will not hold excessive amounts of water.
Established olive trees require regular fertilizing to stay healthy and produce every year. The frequency of the feeding depends on the type of fertilizer used. Do not allow any type of fertilizer to touch the trunk of the tree, as the high levels of nitrogen can cause burns. Feed the olive tree small amounts of fertilizer several times a month. Fertilize two to three times per month to begin, and observe the effects on the tree. Reduce the frequency of feeding if the tips of the leaves begin to turn brown. Increase fertilization up to once per week if leaves begin to wilt or growth becomes stunted. Never fertilize after August or before March.
Use manure or organic compost to feed olive trees without using chemicals. Ensure that the fertilizer chosen is thoroughly decomposed so that the nutrients will be easier to absorb and the chances of over-fertilizing are reduced. Fresh manure should never be used, as it can burn the roots of the tree. Spread 1½ lbs. organic fertilizer over the soil twice monthly.
Feed olive trees a balanced fertilizer with a 16-16-16 nitrogen-phosphorus-potassium (NPK) ratio or similar. Miracle-Gro can also be used to keep the plants healthy. Use slow-release fertilizers if limited on free time, as one application can feed the tree over two to three months. Supplement any chemical fertilizer with an essential minor elements package, which can be purchased in lawn and garden stores. Essential minor elements are nutrients that the plant needs to stay healthy and are not usually found in most fertilizers. All chemical fertilizers should be applied following the manufacturer's instructions.