Managing Nutrition in Floriculture Crops

Establish a good fertilizer program for high-quality spring crops

The only constant during the springtime is change, particularly in the greenhouse industry. For growers, spring can feel like dealing with the indecisive Goldilocks in the classic Three Bears fairytale. The weather is either too hot or too cold. Crops are coming in or going out. Plants are either heavy feeders or light feeders. Establishing a good fertilizer program at this time can be a daunting prospect, especially with the assortment of bedding plants offered today.

John F. Kennedy once said, “The time to repair the roof is when the sun is shining.” The same is true in the greenhouse industry. The slower months prior to the spring season are a good time to get a few tasks, like soil and water testing, crossed off the pre-season checklist. If necessary, preemptive measures can be taken ahead of time to forestall serious nutrition problems later in the season.

Growers who test irrigation water are more aware of immediate problems and of those that may come up later in the season. Soil testing is also an important factor, especially when it comes to soilless substrates. Ideally, regular monitoring of pH levels and soil electrical conductivity (EC) for major greenhouse crops is a good practice in the spring and throughout the season.

The proper management of pH levels in greenhouse plants is always a concern. Dr. Neil Mattson, Assistant Professor and Floriculture Extension Specialist at Cornell University, says that growers can solve a lot of problems in the greenhouse by being pro-active about pH levels. Mattson recommends keeping a basic tool-kit of fertilizers on-hand throughout the season. The toolkit should include: 1) an all-purpose blend-matched to water alkalinity- for everyday use (e.g., 20-10-20, 21-5-20 for moderate alkalinity); 2) a nitrate-based fertilizer for driving up pH (e.g., 15-0-15); and 3) a high ammonium fertilizer (e.g., 21-7-7) for lowering pH.

One of the biggest conundrums growers face is how to meet the diverse nutrient needs of the plants in their greenhouse. Grouping plants with similar nutritional needs together can be helpful in some cases. The best approach is to establish a good base fertilizer feed and then prescriptively treat plants with special nutrient needs. Controlled-release fertilizers (CRFs) work well for supplemental feeding and can be used in combination with water-soluble fertilizers (WSFs). For example, heavy feeders may require the use of a CRF and a WSF.

Managing nutrition for mixed containers and hanging baskets requires special attention. Choosing a combination of plants with similar nutrient requirements is a time-saving practice. Individual plants can also be grown separately for as long as possible and then combined later. Controlled-release fertilizers are often used to provide a nutrition base for combination containers. Be aware of leaching when watering hanging baskets. The best way to combat unhealthy leaching is to avoid overwatering and to monitor the plants located below the hanging baskets closely.

Proper nutrition management in the greenhouse is of utmost importance for high-quality crops. KeyPlex’s micronutrient and biopesticide products ensure that greenhouse crops will grow to their full potential and stay that way.