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Production of organic mother plants under LED artificial light for the production of cuttings and potted flowering plants

Activity summary

Although the organic ornamental horticulture market is still marginal in Canada, the organic production of ornamental plants is in full expansion in Europe and in the United States. Consumers are becoming increasingly aware of the environment, and in how the goods they buy are produced. They are increasingly looking for locally produced plants that reflect their lifestyles and interests, which explains the increasing demand for organic clothing and other organic non-consumables (for example, cosmetics), as well as for equitable products. The sustainability of production systems has also become a very important factor in marketing, and several conventional producers seek to fill the needs of new markets and thus increase their profits.

As a result, this study is a logical follow-up to the research done as part of the first Organic Science Cluster aimed at the organic production of potted flowering plants. During this first phase, it was shown that high quality organic flowering plants can indeed be produced using an appropriate growing medium and basic fertilization, supplemented by a weekly supply of liquid organic fertilizers. These tests, however, were conducted without using growth regulators, which are generally used in the production of potted flowering plants to obtain shorter plants, shorter internodes, better branched plants and more robust stems, while improving plant aesthetics. To respond to this production problem involving the absence of an effective tool for controlling the morphological response of organically produced ornamental plants, the recent arrival of LED (Light Emitting Diodes) technology for horticultural use offers a range of very precise light spectra that can stimulate or inhibit specific morphological and physiological responses, and thus act as growth regulators.

The general objective of this study is thus to develop a system for producing mother plants, cuttings and potted flowering plants under LED lighting to obtain high quality and organically certified cuttings and potted flowering plants. More specifically, we will evaluate the following with four ornamental species:

1. The morphological and physiological differences of the ornamental species and varieties under LED lighting;
2. The quality of cuttings produced under LED lighting compared to commercially used lighting;
3. The potential of LED to serve as a replacement for growth regulators in the organic production of mother plants and potted flowering plants;
4. A suitable organic fertilization for production management using LED lighting;
5. The effectiveness of some wavelengths in reducing plant sensitivity to diseases and pests; and
6. The response of different cultivars to organic management under supplemental LED lighting.

To the best of our knowledge, no study in Canada has proposed such tools to promote the organic production of ornamental plants. The absence of an efficient organically permitted growth regulator, coupled with the difficulty in perfectly controlling plant mineral nutrition to enable the production of plants with a very high visual quality, constitute the main obstacles to the development of this economically important agricultural sector that is organic production.

Materials and Results to Date

• • Acta Hort (2014) 1041: 71-78

• Organic flowers that are good for the environment: Frank Zyromski Greenhouses

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