Avoid Excessive Hanging Baskets in the Greenhouse
Roberto G. Lopez, Ph.D., Associate Professor and Floriculture Extension Specialist, Purdue University
I often see growers placing an excessive number of hanging baskets above their other crops growing on benches or on the floor. This leads to poor-quality crops and the use of additional plant growth regulators (PGRs) to minimize stretching. In this example, the grower has placed a very dense fern hanging basket crop over a low light requiring begonia crops (Figure 1). Although I do not recommend this strategy, it is much better than placing a dense hanging basket crop above medium- or high-light crops, as we can see in this example (Figure 2). This elongated and poor quality geranium was the result of being grown under an excessive number of hanging baskets (Figure 3).
Research has shown that basket color can influence the light transmission to the crop below, with white and green baskets (no plants) providing 13 and 25% shading, respectively. Additionally, under a typical greenhouse hanging basket scenario, shading can be in excess of 45% as plants grow over the sides of the basket.
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Figure 1. A dense fern hanging basket crop placed above a low light requiring begonia crop.
Figure 2. A dense flowering hanging basket crop placed above a geranium crop.
Figure 3. Stem elongation of geranium due to excessive shading from hanging baskets.