# Colored Shade Nets and LED Lights at Different Wavelengths Increase the Production and Quality of Canada Goldenrod (Solidago canadensis L.) Flower Stems

## TL;DR

This study shows that using colored shade nets and LED lights can improve the quality and production of Canada goldenrod flower stems.

## Contribution

The novel finding is that specific combinations of red shade nets and white LEDs maximize stem production and quality in Canada goldenrod.

## Key findings

- Using red shade nets and white LEDs produced up to 4.2 stems per plant and 100.3 stems per square meter.
- Floral stems reached up to 81.35 cm in length with red shade nets and red LEDs.
- Stems under red and white shade nets with LEDs had higher biomass and met commercial standards.

## Abstract

Canada goldenrod (Solidago canadensis L.), a short-day plant commonly cultivated as a cut flower, depends on proper lighting management to obtain long stems and higher commercial value. Thus, this study aimed to determine the effect of modifying the light spectrum through the installation of light-emitting diodes (LEDs) and the use of colored shade nets on the production and quality of Canada goldenrod stems. The treatments used were colored shade nets and different LED lighting treatments. Production per plant and productivity per square meter were determined. Twenty stems were selected and evaluated for: stem length; inflorescence length and width; number of floral ramets per inflorescence; number of leaves; stem base diameter (mm); and fresh stem biomass (g). Canada goldenrod plants require an extension of the light period with artificial lighting to produce higher-quality stems, regardless of whether the bulbs emit red or white light. The use of nets with 50% red and white shading promoted higher production and elongation of Canada goldenrod stems, with a production that reached up to 4.2 floral stems per plant and 100.3 floral stems per square meter using the red shade net and white LED. These floral stems were of high commercial standard, with a length of up to 81.35 cm with the red shade net and red LED, and were 31 cm in diameter for the inflorescences, approximately, under black or white shade nets and white or red LEDs. More robust floral stems with greater biomass were observed using any shade net color and LED lamps.