Things You'll Need
Low nitrogen fertilizer
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.
Healthy trees flower and produce fruit more readily than trees that are lacking in nutrients or water.
Smudging is a traditional Filipino technique for forcing mango trees to bloom: because smoke contains ethylene, it has been effective in causing trees to bloom out of season. Trees that typically bear fruit only in alternate years will also flower and form fruit when you expose them to smoke.
Potassium nitrate is also sometimes called saltpeter.
Low nitrogen fertilizers are available at nurseries and garden supply stores.
Do not use potassium nitrate on mango trees that are younger than 10 years old. Spray flower-inducing potassium nitrate only once each year: The repeated use of potassium nitrate can eventually adversely affect the quantity of fruit a mango tree produces, according to findings presented at the 9th Philippine Fruits Symposium in November 2001.
- University of Hawaii Extension: Mango General Crop Information
- University of Hawaii Extension; Floral Manipulation in Mangos; Tom Davenport
- California Rare Fruit Growers: Mango
- University of Hawaii Extension: Origin and Classification of Mango Varieties in Hawaii
- Philippine Star; Too Much Flower Inducer Spraying Bad for Mangoes; Sosimo Ma Publico; December 2001
- Mango Information Network: Vol. 4 No. 4
Barbara Fahs lives on Hawaii island, where she has created Hi'iaka's Healing Herb Garden. Fahs wrote "Super Simple Guide to Creating Hawaiian Gardens" and has been a professional writer since 1984. She contributes to "Big Island Weekly," "Ke Ola" magazine and various websites. She earned her Bachelor of Arts at University of California, Santa Barbara and her Master of Arts from San Jose State University.