Mangos are one of the special delights of living and gardening in a tropical climate. Most varieties of this sweet, juicy fruit flower in early spring and ripen in summer. However, some varieties are notorious for producing a crop only every other year: if you own a Haden tree, it has the habit of bearing fruit in alternate years. Also, in rainy areas, such as the windward sides of the Hawaiian Islands, spring rains can cause blossoms and fruit to drop prematurely, seriously affecting harvest. Several techniques can help produce the flowers you need to ensure an ample harvest.
Burn a smudgepot or other smoke-producing device near your mango tree in early spring, before flowers form on the tree.
Spray your tree with potassium nitrate, a chemical compound often included in chemical fertilizers. After harvest, wait for trees to begin new growth. Mix 1/3 oz. of this substance to each quart of water and then spray your tree before 9 am or after 4 pm to prevent burning of the leaves.
Apply a low nitrogen, or "blossom booster," fertilizer to your mango tree in early spring before it blooms. Follow product instructions for correct mixing and application procedures.
Fertilize and water your mango tree correctly to ensure it is healthy and well nourished. When you plant your tree, mix super-phosphate fertilizer (0-45-0) in the soil; during the first year, feed with a plant food having an N-P-K ratio of 10-20-20 or select fish emulsion, which is better for young trees. When the tree is older, repeat this application three to four times each year by spreading 10-20-20 granular fertilizer around the tree's drip line. Mulching with organic compost also benefits mango trees.