Propagating chrysanthemum in Rootcubes® / Horticubes® Growing Medium ensures clean and disease-free young plant production
Miriam Ndalila, Technical Consultant Africa, OASIS® Grower Solutions Africa, Nairobi, Kenya
John Kihia, Technical Manager Africa, OASIS® Grower Solutions Africa, Nairobi, Kenya
Vijay Rapaka, Ph.D., Manager, Corporate Grower, Research & Technical Support, Smithers-Oasis Company, Kent, OH USA
The name chrysanthemum is derived from Greek and means “golden flower.” Chrysanthemum belong to the Asteraceae family. Chrysanthemums used in the commercial floriculture industry are a complex hybrid composed of crosses among several annual and perennial species. Chrysanthemums are grown for three reasons in the floriculture industry: cut flowers, potted plants, and garden plantings. All of these can be fulfilled by Dendranthema x grandiflora. Chrysanthemums are propagated using terminal shoot-tip cuttings and they are generally easy to propagate. Chrysanthemums are susceptible to various diseases caused by fungi, bacteria, and viruses. Breeders / stock plant producers control most of these by culture-virus indexing and clean stock plant production procedures. Although the starring plant material may be free of pathogens, the cuttings during rooting are susceptible to infection from soil borne pathogens, if the media is not treated properly. Propagating chrysanthemums in OASIS® Rootcubes® / Horticubes® Growing Medium ensures clean and disease-free young plant production.
- The Rootcubes® and Horticubes® Media are uniquely engineered propagation media.
- The foam media is a thermoset material and is considered to be sterile because of the high temperature involved during the manufacturing process.
- Furthermore, it is formulated with optimal air / water ratio to promote fast and uniform rooting of vegetative cuttings.
- Horticubes® medium is a relatively higher drainage and creates a drier environment at the root zone compared to Rootcubes® medium. Depending on the cultivar requirement and climatic conditions in the greenhouse Rootcubes® or Horticubes® medium can be used for propagation of chrysanthemum cuttings.
Following is the general procedure for propagation of chrysanthemum cuttings in Rootcubes® XP-System* or Horticubes® 276 Plug Sheet:
- Start with clean shoot-tip cuttings harvested from a healthy stock plants.
- The cuttings cab be directly inserted into the propagation media for immediate rooting or can be cold stored under proper conditions without desiccating for several weeks before rooting.
- Prepare the propagation area by placing the foam medium on the bench. Note: The Rootcubes® XP-System (312 count) comes in plastic strips with a sub-irrigation tray. Horticubes® 276 Plugs comes in a sheet format and they can be separated into individual cubes and populated into a propagation tray.
- Thoroughly water the medium with a complete nutrient solution [using a fertilizer similar to 15 (N) -5 (P) -15 (K) and Cal-Mg] at a rate of 75 to 100 ppm N. Complete saturation of the foam can be achieved by sub irrigation or overheard water.
Note: In the case of XP-System, place three strips in the sub-irrigation tray leaving space between strips. Fill the sub-irrigation tray with nutrient solution and this will allow complete saturation of the foam.
Note: If you are using overhead watering to saturate the cubes, consider using a watering hose and a nozzle. It takes several passes to completely saturate the foam medium. Break open and inspect few plugs to ensure the foam is completely saturated or not. Note: Overhead misting is not sufficient enough to saturate the foam medium.
- Insert the cuttings ~25% of the height of the foam.
- Consider using a rooting hormone as it can help improve the uniformity in rooting with chrysanthemum cuttings.
- Misting: The frequency of misting depends on greenhouse conditions such as light intensity temperature, humidity, and also the air movement. Generally, mist for 6 seconds every 8 minutes. Reduce the misting frequency as the cuttings establish in the propagation environment. Never let the cuttings wilt and foam media to dry out excessively during the course of propagation.
- Fertilizer and watering: After 5 days into propagation consider watering with a hose and a breaker every 2 to 3 days with a complete nutrient solution [using a fertilizer similar to 15 (N) -5 (P) -15 (K) and Cal-Mg] at a rate of 150 ppm N.
- Humidity and Air circulation: Maintain high humidity (90 – 100%) levels and reduce air circulation to avoid wilting of the cuttings.
- Light levels: Generally chrysanthemum cuttings can handle higher light during propagation. Shade the propagation environment during afternoon house.
- Temperature: Optimal rooting occurs when root zone temperatures are maintained (usually with bottom heating) between 75° and 80° F (24° to 27° C). The recommended daytime air temperatures are between 76° and 82° F (24° to 28° C) and nighttime air temperature are between 70° to 74° F (21° to 23° C).
- Rooting: Typically it takes about two to three week to root chrysanthemum cuttings and after that they are ready for transplant.
Fig. Commercial propagation of chrysanthemum cuttings in Rootcubes® XP-System (three 52 count strips placed per one sub-irrigation tray – this spacing allows optimal propagation density without overcrowding and also ensures also complete saturation of the media during the course of propagation).
Transplanting Rootcubes® Wedge® or Horticubes® Medium
Chrysanthemums are very prone to soil borne fungal diseases. Therefore, it is recommended to transplant into fumigated or pasteurized media. Rootcubes® Wedge® or Horticubes® media can be transplanted into a pot or a container to be grown inside a greenhouse or in an outdoor location as long as the growing media can be maintained moist with a drip or some other soft of irrigation system until the plants are established. Note: Do not transplant directly into a field where media moisture cannot be controlled using an irrigation system.
Following are the general procedures:
- Fully saturate the Rootcubes® Wedge® or Horticubes® medium before transplant.
- Always transplant into a moist media. Note: Chrysanthemum perform well in properly drained media.
- Note: Once transplanted water quickly moves out of the foam into surrounding matrix. As a result roots grow rapidly into the surrounding media.
- Note: Do not let the foam dry out excessively before or during transplant process.
- Note: Transplanting into dry media can jeopardize the survival of the plant because foam can dry out excessively.
- Thoroughly water the media after transplant. When first transplanted, the rooted cuttings can wilt easily, sprinkle water as required.
- Once established, just water as required. Note: Overwatering can delay the transplant performance because the root will not grow out of foam.
*The XP-System configuration is available in limited areas. Not available in North America.