Fertilizer For Water Grown Plants – How To Fertilize Plants In Water

Plant Growing In A Clear Vase With Water
plant in water
(Image credit: Gardening Know How, via Nikki Tilley)

It’s possible to grow plants in water year-round with very little investment of time or effort. Hydroponic plant environments aren’t as complicated as they sound, as plants grown in water simply need water, oxygen, a jar or other support to keep the plants upright – and, of course, the proper mix of nutrients to keep the plant healthy. Once you’ve determined the best fertilizer for water grown plants, the rest, as they say, is a piece of cake! Read on to learn how to fertilize plants in water.

Feeding Houseplants Growing in Water

Although plants get some important elements from the air, they draw most of their nutrients through their roots. For those grown in hydroponic plant environments, it’s up to us to provide fertilizer in the water. 

If you’re serious about creating hydroponic plant environments, it’s a good idea to have your water tested before you begin. Often, water contains a significant amount of calcium, magnesium, sodium, and chloride, and in some cases, may contain excessive amounts of boron and manganese. 

On the other hand, iron, potassium, phosphorus, nitrogen, and certain micronutrients may be lacking. A water test reveals exactly what your water needs in order for plants to flourish. 

As a general rule, however, feeding houseplants growing in water isn’t that complicated and, unless you’re a chemistry buff, there’s really no need to stress over a complicated formulation of nutrients.

How to Fertilize Plants in Water

Simply add a good quality, water-soluble fertilizer to the container every time you change the water – usually every four to six weeks, or sooner if half of the water has evaporated. 

Use a weak solution consisting of one-quarter the strength recommended on the fertilizer container. If your plants are looking a little puny or if the foliage is pale, you can mist the leaves with a weak fertilizer solution weekly. 

For best results, use bottled spring water, rainwater, or well water, as city water tends to be heavily chlorinated and devoid of most natural nutrients.

Mary H. Dyer

A Credentialed Garden Writer, Mary H. Dyer was with Gardening Know How in the very beginning, publishing articles as early as 2007.