Pineapple plants can be grown as an attractive tropical indoor plant, or in U.S. Department of Agriculture plant hardiness zones 10 and 11 outdoors. The sweet fruit of pineapple is rich in citric acid, potassium, and vitamin C. With a relatively shallow root system, the pineapple plant relies on a complete fertilizing program to supply the necessary nutrients for successful growth and production.
The nutrient nitrogen is essential food for any green plant, but particularly true for young pineapple plants. Young pineapple plants should be feed 1-2 ounces of nitrogen every eight weeks, with the amount increasing by one ounce every 2-3 months. This can be applied in a balanced NPK (nitrogen-phosphorus-potassium) formulated fertilizer that is either worked into the surrounding soil or sprayed in the foliage of the pineapple. As the pineapple plant matures, nitrogen will help increase the fruit size.
Magnesium is an essential nutrient for healthy pineapple growth and helps balance the large amount of potassium the pineapple plant requires. Feeding added magnesium to your pineapple plant will promote carbohydrate and sugar supply to the forming fruit, thus increasing the taste and size.
Pineapple requires high amounts of potassium before the flower forms to aid in the development of fruit size, plant growth and flavor. The fertilizer formula for mature, before flowering, a pineapple should contain twice as much potassium as nitrogen. Potassium-rich fertilizer needs to be applied both in the soil and by foliage spraying.
Phosphorus is not as high a nutritional requirement for pineapple as nitrogen and potassium. Therefore, apply a balanced fertilizer of nitrogen, potassium and phosphorus as directed, then supplement your pineapple feeding with additional nitrogen and potassium feedings.
Depending on your soil, which should be tested prior to planting pineapple for nutritional content, you may need to supplement the nutritional needs of your plant. The micronutrients of iron, manganese and zinc are necessary to the growth and development of your pineapple. Apply a micronutrient spray containing these components two or three times a year during the warm months. Be sure to follow the directions on the package to avoid leaf burn.