How To Fertilize Water Plants


Aquatic plants add color to backyard water features while also providing cover for fish or shading and preventing algae growth in the pond. There are many varieties of water plants, including emergent plants that have their roots in the water and their foliage or flowers above water, and submerged plants that grow completely beneath the water surface. Aquatic plants only require fertilization when they are actively growing, usually from spring until fall. Water plants are heavy feeders, according to Iowa State University Extension, so implementing a regular fertilizing schedule is necessary.

Step 1

Push a slow-release fertilizer tablet into the soil at the time of planting. Use a 20-10-5 or 5-10-5 analysis fertilizer and apply at the rate recommended for the particular plant. Apply 4 ounces of fertilizer per every cubic foot of soil for water lilies and lotus, and half that rate for other water plants.

Step 2

Fertilize water lilies and lotus once a month during the spring, summer and fall. Apply a fertilizer tablet, following the same rate as used at planting.

Step 3

Feed all other water plants a second time at mid-season. Apply half the rate of fertilizer as that used for lilies.

Step 4

Stop fertilization treatments on perennial water plants in fall, six to eight weeks before the first expected frost. Lack of fertilizer helps encourage these plants to enter dormancy for winter.

Tips and Warnings

  • Always verify the fertilizer amount to apply for the particular water plant and brand of fertilizer you are using. Over-fertilizing can damage plants.

Things You'll Need

  • Fertilizer tablets


  • Iowa State University Extension: Water Gardening: Aquatic Plants
  • University of Illinois Extension: Water Gardening
Keywords: fertilizing water plants, feeding aquatic plants, pond plant care

About this Author

Jenny Harrington has been a freelance writer since 2006. Her published articles have appeared in various print and online publications, including the "Dollar Stretcher." Previously, she owned her own business, selling handmade items online, wholesale and at crafts fairs. Harrington's specialties include small business information, crafting, decorating and gardening.