September 20, 2011

In the past several years, tough economic conditions have hit many industries, including nurseries. One area where nursery owners may be able to save money is monitoring the efficiency of applied nutrients to their container plants, said Winston Dunwell, extension professor for nursery crops with the University of Kentucky College of Agriculture.

For the past two decades, Dunwell has used pour-through monitoring to conduct research on the pH and effectiveness of fertilizers in container plants. In the pour-through technique, additional water is applied after the crop has been irrigated. The water leaches through the media into another container, and then a meter detects the container media pH and estimates the nutrients based on the level of soluble salts.

“It’s important for container plants to look good all the time, because someone could order at any time,” Dunwell said. “But growers also don’t want to over fertilizer, because that costs them time and money and negatively affects the environment. Nutrient monitoring is one of the best ways for growers to ensure their plants are getting the nutrients they need without applying excess fertilizers.”

In the past several years, nursery growers approached Dunwell because their container plants weren’t actively growing or looking as good during the middle of the growing season. Through nutrient monitoring and funding from the Kentucky Horticulture Council and the Kentucky Agricultural Development Fund, he was able to find the cause.

“Growers were using slow release fertilizers that should have given their plants nutrients through the growing season, but the plants were running out of fertilizer in June and were losing three months of growth due to the effects of hot weather and frequent watering on the fertilizer,” he said.

Dunwell has begun trials for nutrient monitoring with long season, 12- to 14-month controlled-release fertilizers. He and Carey Grable, UK extension associate for nursery crops, are developing an extension publication on nutrient monitoring and his findings. This publication will be announced via social media, the UK IPM Nursery Crops Blog and the Kentucky Nursery Listserv. Links to these are on the UK Research and Education Center Nursery Crops Development Center site at

More information on pour-through nutrient monitoring and nursery and landscape management is available on the UK Horticulture website at