Geranium Leaf Yellowing: Causes and Solutions

Advice: Spraying geranium cuttings with 2.5 ppm Fascination during the first or second day of propagation resulted in reduced leaf yellowing. Fascination is a mixture of two plant hormones, gibberellin (GA4,7) and a synthetic cytokinin (N-6-benzyladenine).

TitleEthanol treatment induces compact growth in Kalanchoë

Advice: Denatured alcohol, which is ethanol treated with benzene and/or other chemicals to prevent its consumption by humans, was shown to be just as effective as a plant growth retardant when used as a 2% growing media drench to reduce the growth of potted Kalanchoe plants.  In addition, ethanol has been shown to be effective in extending the longevity of many floral crops as indicated by the fact that there are presently 57 ethanol-related articles in the Chain of Life Network® database, which is in the Care, Handling, and Marketing Recommendations for Floral Crops eManual.  Presented below are four examples of article titles in this database. Finally, using ethanol to improve the growth and/or postharvest longevity of floral crops has many advantages such as it is biodegradable, easy and safe to use, and is relatively inexpensive.

- Opening and vase life extension of peach flowers on detached shoots with sucrose and ethanol
- Inhibition of ethylene synthesis and senescence in carnation by ethanol
- Using alcohol to reduce growth of paperwhite narcissus
- Ethanol and other compounds retard leaf senescence and improve the vase life and quality of cut chrysanthemum flowers

Title: Validation of the effects of a single one second hypochlorite floral dip on Botrytis cinerea incidence following long-term shipment of cut roses

Advice: Roses dipped for one second in a solution containing 150 mg/liter hypochlorite (bleach) provided as good or better Botrytis control than commonly used fungicides, reduced water loss, and was effective up to one day of use. It matters not the source of the bleach, but solutions generally sold for home use often worked better than just the straight hypochlorite, probably due to the addition of wetting agents. In addition, inner rows of flowers in bunched roses have a higher incidence of disease than the outer row.

Gray Mold Severity and Vase Life of Rose Buds after Pulsing with Citric Acid, Salicylic Acid, Calcium Sulfate, Sucrose and Silver Thiosulfate

Advice: Botrytis severity was reduced by 15-88% and vase life increased by 20-37% when freshly harvested roses we placed into a solution of silver thiosulfate (STS) and calcium chloride (5.6 grams per liter) for 15 hours prior to being stored and/or shipped.

Stem bending in cut Gerbera jamesonii flowers: Effects of a pulse treatment with sucrose and calcium ions

Advice: Placing freshly harvested gerbera in a solution of 25 grams sucrose (table sugar), 5.6 grams calcium chloride, and 400 mg citric acid (pH 3.5) per liter of water for 24 hours decreased subsequent stem bending during vase life studies.

Effects of CO2 enrichment on photosynthesis and growth in Gerbera jamesonii

Advice: Adding carbon dioxide to greenhouses where gerbera are being grown can increase flower number, size, and vase life as well as improving flower color and increase peduncle (stem) length.

Postharvest Life of Gladiolus grandiflorus L. cv. Jessica as Influenced by Pre-harvest Application of Gibberellic Acid and Kinetin.

Advice: Soaking gladiolus corms overnight before planting and spraying the foliage to run-off 45 days after planting using a 100 ppm (100 milligrams per liter of water) solution of gibberellic acid (GA3) resulted in numerous benefits including more open and longer lasting florets per spike, longer lasting spikes, and enhanced floret color. While not discussed in the article, it is suggested that a liquid or salt version of GA3 be purchased such that it will mix better with water.