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Phosphate for Plants Vs. Root Stimulator

By Liz Jamar ; Updated September 21, 2017
Massive tree roots.

Getting your plants off on the right start is a key to their future growth. Since soil types differ all over the United States, some gardeners may have to give their plants a boost by using a high phosphate fertilizer. In some parts of the U.S., though, a high phosphate fertilizer may not be an option, so gardeners can use root stimulator. Regular soil testing should be done to determine your need.

The Label

Before you consider the differences in root stimulators and high phosphate fertilizer, take a look at the label on both products. On all fertilizers are labeled with three main numbers. You have probably noticed them on the package in this form: 10-50-10. This is the nitrogen-phosphorus-potassium ratio or N-P-K. These numbers represent the percentage (by weight) of the three major nutrients required for healthy plant growth, always in the same order: N-P-K. All fertilizers are required, by law, to have the N-P-K ratio on the label.

Root Stimulator

Root stimulator is a product designed to help plants build a strong root system when they are first planted. It also helps maintain a strong root system for established plants. In addition to having the basic fertilizer ingredients nitrogen, phosphorus, and potassium, root stimulator also contains a hormone that high phosphorus fertilizers do not have: Indole-3-butyric acid or IBA. IBA is used because of its similarity to naturally occurring substances that help in root development. This hormone encourages speedy root development and growth. Not all root stimulator contains N-P-K, but they all include the hormone IBA.

High Phosphate Fertilizer

High phosphate fertilizers help blooming plants to bloom longer.

High phosphate fertilizer is fertilizer with a high middle number in the N-P-K ratio, like 10-50-10. A majority of these are either in a water soluble form or a time-release granule. This type of fertilizer encourages a blooming plant to bloom longer and more profusely. It also aids in root growth, but lacks the developmental hormone IBA.

What to Use

Root stimulator should be applied at the time of new plantings. It works on anything you will plant in your landscape, including trees, shrubs, and flowering plants. It even works on freshly sodded grass because it does not have the high levels of N-P-K that can sometimes burn new root systems. High phosphate fertilizers can be used on more established plants to promote blooming or to give the roots a healthy boost through periods of stress.

How to Use

Make sure you read and follow the directions carefully on any fertilizer or root stimulator product, as overuse can cause damage to your plants. Many of the manufactures have the product label available on their website if your label becomes unreadable. Or check with a local certified nursery professional where you purchased the product. Often if they have it in stock you can get a copy of the directions.


About the Author


Based in Dallas, Liz Jamar has been writing gardening and houseplant articles since 2008. Her work has appeared in "Lit Monthly" magazine. Jamar is a Texas master certified nursery professional and is pursuing a B.F.A. in creative writing from Full Sail University.