Purdue University’s Roberto Lopez, the University of New Hampshire’s Brian Krug, the University of Maine’s Stephanie Burnett and Cornell University’s Neil Mattson established the Floriculture Sustainability Research Coalition (FSRC) three years ago. The FSRC’s goal is to provide information to the greenhouse industry about sustainable growing and business practices through multi-state research and Extension activities. Here’s a look at yet another research group worth supporting and some of the projects they’re working on:
Low Or No-Heat Bedding Plant Production
Multi-year and collaborative research at Cornell and Purdue is shedding light on how growers in temperate climates can finish high-quality, sustainably produced bedding plants and hanging baskets with low or no heat for the Mother’s Day market. Mattson, Lopez and their students are quantifying time to flower and growth difference between bedding plants produced in a greenhouse with a temperature set point of 65°F and an unheated high tunnel. Figure 1, for example, shows that time to flower of petunia transplanted on April 1 is only delayed by three days when produced in an unheated high tunnel.
Research has been conducted at New Hampshire, Cornell and Purdue on controlled-release fertilizers (CRFs) to determine how they perform against water-soluble fertilizers. The team has trialed CRFs on angelonia, argyranthemum, calibrachoa, coleus, cyclamen, diascia, garden mums, geraniums, lantana, New Guinea impatiens, petunia, poinsettia, and sutera.
When CRFs were incorporated into substrates at a rate of 1.1 pounds N/yd3, similar growth occurred with CRFs compared to using a constant liquid feed program of 200 ppm N (Figure 2).
Organic Substrates & Fertilizers
Research at Maine and Cornell has determined appropriate fertilizers and substrates for use in organic greenhouse production. Fertilizing plants with Drammatic ONE and Daniels Pinnacle resulted in similar growth of tomato and petunia compared to plants fertigated with 21-5-20. Leaching of nitrate and ammonium was lower in organic fertilizers compared to the conventional fertilizer. However, the cost of liquid organic fertilizers was 5.0 to 7.8 cents per pot compared to 0.7 cents per pot for conventional fertilizers.
The FSRC team has used a variety of organic substrates to produce plants, including Fafard and SunGro organic. If growers wish to produce plants in a substrate with higher fertility to offset the cost of organic liquid fertilizers, a 1:1:1 mixture of peat, perlite and compost provides about four weeks of fertility. The team also recommends growers use the Solvita test kit to ensure they use a mature compost.