Galaxy Streptocarpus
Introduction: The Galaxy series of streptocarpus program offers several significant improvements to commercial growers, including: more compact foliage, flower clusters with increased “bell” counts, and flowers that are borne closer to the foliage, and a wide range of colors including solids and complex color patterns.
Culture – Light: Streptocarpus are part of the gesenariad family require lower light regimes to produce high quality foliage and high flower counts. Light intensities should be maintained within the 1,000 to 1,500 foot-candle range. Under summer conditions, the light intensity should be maintained within the 1,000 to 1,200 foot-candle range. Higher light accompanied with higher leaf temperatures can also result in a leaf “scalding”.
Streptocarpus will flower all year long, but with the longer days the flower response time is faster and the flower counts are significantly higher. Assimilation lighting during the winter months would reduce the flower response time and increase flower times.
Culture – Temperature: Streptocarpus require a warm greenhouse environment to promote the highest quality plants. Day heat to temperatures should be maintained between 65º to 68º F, with ventilation starting when the greenhouse temperatures exceed 75º F. Night temperatures should be maintained at 65º F. Warmer temperatures will cause the foliage to become pale and reduce the flower life. Colder temperatures will significantly reduce the foliage growth and lengthen the flower response time. Cooler temperatures will also increase the incidence of root and crown rots.
Culture – Transplanting: Streptocarpus should be transplanted into a well drained, low EC substrate. When transplanting the rooted cutting plug, the top of the original plug should be at the soil level or slightly higher after initial irrigations. The planting depth is very critical on this crop. If plugs are planted too deeply crown rot could become evident resulting in low vigor or losses. Transplanting the original plugs to high will not provide a proper anchor in the substrate and result in a “floppy” plant.
Culture – Fertility: Streptocarpus are relatively “light” feeders. EC’s in the substrate should be maintained below 1.0, and the substrate pH maintained around 6.0. A constant liquid fertilization program of 125 to 150 ppm N using 15-15-15 should be initiated as soon as the initial plug has rooted into the substrate and continued until significant color is visible. Once significant color is visible this rate should be reduced by 50%. This can be accomplished by alternating fertilizer with clear water irrigations.
Insects and diseases: Streptocarpus are fairly resistant to insects and diseases. The literature has cited the ability of aphids, cyclamen mites, thrips, whiteflies and mealy bug to be able to be sustained on commercial crops. The most common disease issues with this crop are botrytis and a crown rot. Botrytis can be controlled using proper environmental controls and a bi-weekly application of a fungicide with a high efficacy rate against this pathogen. Crown rot can be controlled by managing the transplanting depth to avoid burying the original crown and the use of a broad spectrum fungicide. Please consult local rules and regulations on fungicide selection and follow labeled instructions.