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Light Cuttings At the time of potting, providing supplemental shading is critical for limiting stress on the cutting and good cutting establishment. Shading (from 25% to 50%) will help the plants acclimate to the new higher light and lower humidity environment. Growing Some recommendations suggest that the number of breaks can be increased if the plants are shaded until 10 days after pinch. After the plants are established and pinched the amount of light should be gradually increased. Poinsettias should be grown with 4,000 to 5,000 footcandles of light. The proper light intensity promotes stocky plants with thick stems. Excessively high light levels can cause leaf puckering or drooping leaves. Leaf scorch can also be a minor problem when the plants are exposed to full intensity of the sun just after the shade cloth is removed.
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Low light levels can result in lower leaf loss, small bracts, blueish bracts, and elongated internodes (stretch) especially for plants at the center of the bench.
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Poinsettias are particularly sensitive to stray light during the flowering process. While a light intensity of only 1 or 2 footcandles at night will not prevent flowering, it can result in the development of malformed inflorescence (see: Splitting) or a delay in flowering. Higher amounts of stray light can delay flowering. The grower must take every precaution to eliminate unwanted lights on the plants at night. Sources of stray light can be street lights, flashlights, lights from adjacent buildings or greenhouse sections, or automobile lights. (Two footcandles of light is the minimum intensity at which most individuals can read a newspaper.)
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Sample poinsettia production schedules. |
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Hegg Types, Lilo, Supjibi, Celebrate 2, Merrimaker, Yuletide, Freedom |
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Activity |
Single Stem, 3 plants / 6" pot |
Pinched, 1 plant / 6" pot |
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Flower November 26 |
Flower December 10 |
Flower November 26 |
Flower December 10 |
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Propagation |
July 30 (4 weeks) |
Aug. 13 (4 weeks) |
July 16 (4 weeks) |
July 30 (4 weeks) |
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Pan |
Aug. 27 (2.5 weeks) |
Sept. 10 (1 week) |
Aug. 13 (3 weeks) |
Aug. 27 (3 weeks) |
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Pinch |
--- |
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Sept. 3 (1.5 weeks) |
Sept. 17 (0 weeks) |
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Lights On |
Sept. 15 (1.5 weeks) |
Sept. 17 (3 weeks) |
Sept. 15 (1.5 weeks) |
Sept. 17 (3 weeks) |
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Lights Off |
Sept. 24 (9 weeks) |
Oct. 8 (9 weeks) |
Sept. 24 (9 weeks) |
Oct. 8 (9 weeks) |
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Flower |
Nov. 26 |
Dec. 10 |
Nov. 26 |
Dec. 10 |
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Night Temperatures |
July 30 - Aug. 26 (70°F) |
Aug. 13 - Sept. 10 (70°F) |
July 16 - Aug. 12 (70°F) |
July 30 - Aug. 27 (70°F) |
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Aug. 27 - Nov. 26 (65°F) |
Sept. 11 - Dec. 10 (65°F) |
Aug. 13 - Nov. 26 (65°F) |
Aug. 28 - Dec. 10 (65°F) |
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Source: P.A. Hammer, Purdue University |
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Sample poinsettia production schedules. |
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V-14 Types, Peppermint, Regal Velvet, Red Sails |
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Activity |
Single Stem, 3 plants / 6" pot |
Pinched, 1 plant / 6" pot |
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Flower November 26 |
Flower December 10 |
Flower November 26 |
Flower December 10 |
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Propagation |
July 30 (4 weeks) |
Aug. 13 (4 weeks) |
July 9 (4 weeks) |
July 23 (4 weeks) |
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Pan |
Aug. 27 (2 weeks) |
Sept. 10 (2 weeks) |
Aug. 6 (3 weeks) |
Aug. 20 (3 weeks) |
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Pinch |
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Aug. 27 (2 weeks) |
Sept. 10 (2 weeks) |
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Black Cloth |
Sept. 10 (1.5 weeks) |
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Sept. 10 (2 weeks) |
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Natural Days |
Sept. 24 (9 weeks) |
Sept. 24 (11 weeks) |
Sept. 24 (9 weeks) |
Sept. 24 (11 weeks) |
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Flower |
Nov. 26 |
Dec. 10 |
Nov. 26 |
Dec. 10 |
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Night Temperatures
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July 30 - Aug. 26 (70°F) |
Aug. 13 - Sept. 10 (70°F) |
July 9 - Aug. 6 (70°F) |
July 23 - Aug. 20 (70°F) |
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Aug. 27 - Nov. 26 (65°F) |
Sept. 11 - Dec. 10 (65°F) |
Aug. 7 - Nov. 26 (65°F) |
Aug. 21 - Dec. 10 (65°F) |
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Source: P.A. Hammer, Purdue University |
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