6/9/2026 - By Chad E. Keel

POLYON® Mini NPK has become an essential nutrient management solution in horticulture due to its precision, efficiency, and long-lasting performance. Horticultural crops such as ornamental plants, flowers, and greenhouse vegetables require balanced nutrition for optimal growth and appearance. The POLYON® controlled-release fertilizer (CRF) mini prill is specifically designed to meet the plant demands by delivering nutrients gradually over the required crop cycle.

POLYON® Mini Provides Consistency in Small Media

The POLYON® “mini prill” refers to the small, uniform granules used in the fertilizer formulation. These compact granules are particularly beneficial in horticultural growing systems where even nutrient distribution is critical. In container production, plug trays, hanging baskets, and potted ornamentals, mini prills can be mixed thoroughly into growing media to ensure consistent nutrient availability throughout the root zone. The size and distribution of fertilizer granules are what set this product apart, allowing it to take up less space in the growing media without sacrificing nutrient load.

When comparing our standard-sized POLYON® prill to the mini prill, we see a tremendous difference. Size guide number, or SGN, in fertilizer describes the size of the granule being used. A standard POLYON® NPK prill (SGN 297) contains 40 prills per gram, while the POLYON® mini prill (SGN 170) has 204 prills per gram. This provides excellent product distribution throughout the soil and root zone, making the mini prill the perfect profile size for smaller growing media or areas of application.

The Benefits of POLYON® Mini 14-4-14

The POLYON® 14-4-14 blend is a desired formula for its nutrient ratio and crop safety. The 1:1 N-to-K ratio provides the grower with proper nutrient levels to produce a fantastic crop. The product has a lower phosphorus level to help prevent plant stretch; the nitrogen and potash support plant growth and flowering while also providing important micronutrients to the crop, and the 14-4-14 gives crops exactly what they need. Growers have found success using the product at many different rates, depending on their growing requirements.

When using the POLYON® mini prill in conjunction with water-soluble fertilizer, we recommend 1.5-3 lbs. per cubic yard depending on the PPM used. When used as a stand-alone product, the POLYON® mini prill can be applied at 2 lbs. on the low side and up to 6 lbs. on the high side. As with any fertilizer blend or prill size, we recommend contacting your local Harrell’s Rep to discuss the exact rate needed for each application.

Let Your Local Harrell’s Rep Be Your Guide

The POLYON® mini fertilizer is highly valuable in greenhouse and nursery operations where labor efficiency is essential. It can provide nutrition for several months, allowing growers to reduce the frequency of fertilizer WSF applications. This decreases labor costs, simplifies crop management, and minimizes the risk of human error associated with repeated feeding schedules. While most growers are reluctant to increase plant costs, the POLYON® mini prill can help them reduce plant costs while delivering the same or better plant quality.

Due to the efficiencies listed above, the POLYON® mini prill is a must-have when producing in small containers. If you have any further questions on POLYON® Mini or what blend will be most beneficial to your operation, connect with your local Harrell’s Rep. They are your best resource for all of your fertility needs.

Authored by Chad E. Keel