Zeolite in hydrangea production
The objective of this study was to validate the performance of zeolite from International Zeolite Corporation (IZC) as a media supplement that may increase cation exchange capacity (CEC) and media weight during a complete hydrangea crop cycle at a commercial growing facility in Ontario.
Conventional media for growing hydrangeas has proven too lightweight for a crop that is grown outdoors in a field during the summer. Damage and labour costs are not insignificant when hydrangeas are blown over by wind. Traditionally, clay was added to peat-based media to increase the bulk density, but this media has become too costly. Alternative media, such as wood fiber, have shown some success, but they suffer from compaction during the long hydrangea crop cycle and have limited CEC. As zeolite does not biodegrade nor compact and has excellent CEC, it might prove to be a superior alternative for outdoor production of long-term crops such as hydrangea.
The Horticultural & Environmental Sciences Innovation Centre (HESIC) research team monitored parallel crops of hydrangea grown at the Kamps Hydrangea commercial growing facility, located in Vineland Station, Ontario, from June to October 2021, and at the Niagara College (NC) Teaching Greenhouse, located in Niagara-on-the-Lake, Ontario, from January to March 2022, to compare overall performance between those grown in conventional and zeolite-enriched media. Results from this trial indicate that when zeolite is blended into media to increase overall weight at rates between 5% to 20%, it has no negative effect on the growth of hydrangea. While flower sizes were comparable between the control (grown in media with 5% clay) and the zeolite blends, this study indicated that the number of flowers per plant may decrease with the inclusion of zeolite. The rate of 5% zeolite blended into media was indicated in this study to lead to the lowest number of flowers per plant yet resulted in the largest flower sizes. As such, the addition of zeolite to hydrangea pots in place of clay, may be a viable and more cost-effective alternative for hydrangea growers to consider.
Funding: The project is funded in part by the Niagara College-led Greenhouse Technology Network (GTN), and by the Government of Canada through the Federal Economic Development Agency for Southern Ontario.