Propagating Poinsettia's The following is an excerpt from a publication from Alabama Extension Service. Bear in mind before you read this that it is geared toward the professional production of Poinsettias and appropriate judgment will be needed in order to scale it down to reasonable home use. While the below techniques are designed at the maximum production of a large number of plants, the basic principles remain the same. While it is not necessary to follow each one of the below steps, bear in mind that your success percentage will also be accordingly smaller. However, I think every gardener should give this a try and even if you are able to use only a few of the methods outlined and you have only one in ten cuttings root, this is still success in and of itself and one more than you had before. I have also included a few notes (written in red) where appropriate. Professional growers may start a Poinsettia crop in four ways: 1) order cuttings to grow stock plants from which cuttings are taken for production, 2) order unrooted cuttings to root in house for production, 3) order rooted cuttings that are transplanted to the finishing containers, or 4) order prefinished plants already established in the final container. Regardless of the method chosen, it is essential to order the highest quality propagation material that is certified free of diseases. The choice among these alternatives is largely based on economics and available greenhouse facilities. Few growers in Alabama grow their own stock plants because they occupy a lot of greenhouse space for a long period of time, are difficult to keep pest free, and require a lot of production inputs. Therefore, this publication will not discuss the culture of that option. Your cuttings will come from 3" to 4" cuttings from your own plants. If taking cuttings from longer stock, make sure to keep the orientation of the cutting correct and keep the tip end pointing up.Sanitation is probably one of the most important aspects of Poinsettia propagation (this holds true with all forms of propagation including seeding). All surfaces should be disinfected before cuttings are stuck, including floors, benches, and intermittent-mist equipment. All weeds should be removed from the propagation area because they may host many insects, including whiteflies, fungus gnats, and spider mites. All employees handling cuttings should wash their hands with soap and water, then rinse with a disinfectant before and after handling cuttings. If the lower leaves on cuttings begin to yellow and abscise during propagation, clean them up promptly. The rooting potential of Poinsettia cuttings in propagation is influenced by the age of the shoots on the stock plants from which cuttings are taken, the size of the cuttings, environmental conditions during propagation, and cultivar rooting potential. Good quality unrooted cuttings should be 2½ to 3 inches long with two fully expanded leaves if direct stuck in the final container or one fully expanded leaf if stuck in high density cubes or strips plus a third leaf not yet fully expanded. The stem diameter should be about the thickness of a pencil. Cuttings that are older or larger are more woody and may be more difficult to root. On the other hand, smaller, thinner cuttings may also be difficult to root and may be lost to environmental stress or diseases. Thin cuttings have also been found to increase the incidence of stem breakage at the end of the crop. Cuttings should have green leaves (no yellowing), an active growing point, and be free of insects and diseases. If variation in cutting size exists, grade the cuttings by size and stick the different sizes in separate propagation containers. Unrooted cuttings are usually received from mid-July to August, a time of year when care must be taken to control moisture stress. Cuttings should never wilt! Therefore, be prepared to stick unrooted cuttings as soon as possible after receiving them. Alternatively, cuttings can be stored in a cooler at 45°F for up to three days. Some growers apply a rooting hormone while others do not. If used, apply 1,500 to 2,000 parts per million (ppm) IBA or NAA either as a talc formulation or in an aqueous solution. Apply only to the cut base of the stem. Do not dip the base of the cutting in the solution or talc because this may spread diseases. An aqueous solution can be applied to the base of the cuttings with a mist bottle, and talc can be applied with a puff duster. Cuttings should be stuck in the rooting medium so that leaves do not cover the shoot tip of adjacent cuttings. Stick the cutting no deeper than ¾ to 1 inch. Some growers apply a surfactant as a foliar spray after sticking the cuttings to encourage mist water to spread uniformly over the leaf surface. Follow the manufacturer's recommendations for rate and application frequency. Media used for rooting Poinsettia cuttings may be trays filled with peat lite (50/50 mix of perlite and milled and sifted sphagnum peat moss) medium, Jiffy 7's, Jiffy 9's, peat blocks, Oasis (florists wet foam), or Root-Cubes. Cuttings also may be stuck directly in the final container. Thoroughly water the rooting media well in advance of sticking the cuttings. The propagation temperature should be 72 to 75°F at night and 80 to 85°F during the day Heat mats with adjustable thermostats work very well). Light levels should start at 1,200 to 1,500 foot-candles and be increased to 2,500 to 3,000 foot-candles during propagation (an artificial light garden or hotbed with appropriate shade clothes are your best bets and use a light meter). Too much light will promote wilting and cause bleaching of the leaves. Excessive mist also will be required. Too little light will slow rooting and cause the cuttings to stretch. Shading of the propagation area will be needed at this time of year, preferably adjustable shading. The mist system should deliver a very fine mist capable of uniform coverage of all cuttings (fine mist nozzles like those used for air cooling attached to an adjustable timer and water system. I have found an electronic irrigation timer works pretty well but may be a little difficult to program for some models.). The mist frequency is dictated by environmental conditions and should be monitored hourly in the first 8 to 10 days. A mist controller that can adjust mist frequency based on ambient light levels in the greenhouse is helpful. The mist frequency should be enough to keep stems turgid, although the leaves may sag for the first few days. Do not apply so much mist as to leach nutrients from the leaves, wet the media, and increase the chance of disease problems. It is preferable to increase the amount of shade on the greenhouse than to apply too much mist. Too little mist, on the other hand, will cause leaf wilting to the point of curling and delay rooting. A suggested frequency is 12 seconds on every 4 to 6 minutes for the first 3 to 4 days. During hot weather, many growers apply mist at night once per hour for the first 3 days. Some air movement in the propagation house is beneficial as long as it does not interfere with the mist coverage. After about 8 to 10 days, callus should form at the base of the cuttings and mist frequency can be reduced to every 8 to 10 minutes. By 14 to 18 days, roots should be present and the mist can be reduced to every 30 minutes. Most timers available to home gardeners will not have these fine adjustments. So plan on providing some form of clear enclosure to hold humidity in and mist less often but longer in order to accommodate the smallest adjustments of your timer available. A programmable electronic hose timer that will allow you to turn on and off every 15 minutes (minimum) would work for our purposes here and if we could program smaller increments, even better. A small fan just large enough to keep the air moving is also a great help in success with cuttings. Fertilization of the cuttings can begin at the time cuttings callus using 125 ppm nitrogen from a balanced fertilizer. This is applied once a day after the mist is turned off in the evening. Rinse the foliage after fertilization with clear water to prevent crystallization of fertilizer on the petioles. Fertilizer rate can be increased to 150 ppm nitrogen when roots appear and gradually increased to 200 ppm nitrogen just before potting. Keep in mind, however, that high fertility in high density cubes or strips can cause more rapid stretching than can be controlled using growth retardants. Use an organic, slow-release fertilizer at half strength over the surface of the media and then add additional fertilizer to the potting mix. Many growers begin applying growth retardant to cuttings while in propagation, often beginning 10 to 12 days after sticking. Cycocel at 1,000 ppm plus B-Nine at 1,250 ppm is used and may be reapplied after 5 to 7 days as needed. These applications are made after the mist is turned off in the evening. It is important to prevent the rooted cuttings from stretching in propagation by applying growth retardant and increasing light levels. Cuttings are usually ready to transplant in 3 to 4 weeks after sticking. Home gardeners can best control this by gradually increasing the light levels every week to your cuttings. This is where a hotbed with various densities of shade cloth coverings come in handy. Whether the cuttings are rooted in-house or are ordered from a supplier, it is vital for the grower to be prepared to pot the cuttings immediately by having pots, potting media, labels, and any necessary chemicals on hand. The greenhouse should be prepared to receive the plants by performing cleanup and sanitation tasks and adding overhead shade beforehand. If the rooted cuttings are purchased from a supplier, examine them carefully for quality and freedom from insects and foliage and root diseases as soon as they arrive (this is just as important for purchased unrooted cuttings and prefinished plants). The cuttings should be compact and adequately fertilized, but not stretched or showing symptoms of excessive application of growth retardant. The roots should be white in color and adequately fill the propagation media without being root-bound (excessive roots). Poorly rooted, stretched, or damaged cuttings or cuttings with disease or insect problems can be very difficult to grow into a quality finished product. It is best to plant the cuttings in their final containers upon receipt. (start with 6" pots for your rooted cuttings) If this is not possible, place them in a greenhouse under 50 percent shade, and keep them well watered. Do not wait more than a few days before planting, and do not stress the cuttings. Largely, the choice of container sizes for Poinsettias is determined by the market. By far the most popular container size is the 6-inch pot, though Poinsettias are commonly grown in pot sizes ranging from 4 to 10 inches. Four- to 6-inch pots are usually planted with one rooted cutting per pot that is pinched. Larger pots may be planted with more than one cutting per pot: typically, two cuttings per 7½-inch pot, three cuttings per 8½-inch pot, and four cuttings per 10-inch pot or hanging basket. Special hanging baskets with side pockets are available for Poinsettias, and stock plants may be forced for large specimen plants. Special schedules and techniques are also used to grow Poinsettia trees. When transplanting rooted Poinsettia cuttings to final containers, always make sure the potting medium is moist and plant shallow—no more than one-fourth inch deeper than in propagation (use your standard rule of planting at the same depth as growing). Deep planting can cause poor root development and increase the potential for disease. If the cuttings were rooted in artificial cubes or blocks, do not plant too high or the propagation material will act as a wick and dry the roots (make sure this material is covered or torn away from the plant without damaging the roots). Newly potted cuttings should be watered immediately, preferably with a broad-spectrum fungicide. If not, fungicide should be applied in the first 1 to 3 days after potting (a good quality fungicide treatment [organic or otherwise] is a good idea with all new cuttings). The cutting should be misted or syringed by hand several times a day under warm conditions until root growth begins. Many growers use 50 percent shade (3,000 foot-candles) on newly potted cuttings to reduce the greenhouse temperature. However, the shade should not be used for longer than 7 days, or weak stems will develop. Some growers apply a pre-pinch growth retardant to transplanted cuttings if they are growing rapidly to keep the cuttings compact. B-Nine at 1,250 ppm plus Cycocel at 800 ppm works well (home gardeners should practice pinching and leave the chemicals to the professional growers) . Begin scouting for insects and disease early, and be prepared to take action. These problems are easier to control early, before the plant canopies become dense. Potting media for growing Poinsettias should be course and exceptionally well drained. The pH should be 5.8 to 6.5. Poinsettias have higher requirements for calcium and magnesium than many crops. Therefore, add dolomitic limestone (at least 10 percent magnesium) at a rate of 8 to 10 pounds per cubic yard of potting mix. Super phosphate is usually added at a rate of 4.5 pounds per cubic yard. Epsom salts is added at a rate of 0.25 pound per cubic yard and micronutrients, at the rate recommended by the manufacturer. A starter supply of nitrogen and potassium is also added as calcium nitrate and potassium nitrate each at 0.5 to 1.0 pound per cubic yard. Use a good quality of slow release organic fertilizer with greensand at planting time and add additional calcium and Epsom salts to your mix. One cubic yard is equal to 27 cubic feet. One cubic foot of material (normally 1 medium sized bag of potting soil) is probably the smallest amount you will mix at one time and will fill 4 to 6, 6" pots, so divide the above numbers by 27 to arrive at the quantity for a cubic foot.Give rooting your own Poinsettia cuttings a try and have your own Poinsettia gifts to give away next Christmas or just have enough to fill your home with beautiful Christmas color. Back To Top
Grateful acknowledgement is given to: Alabama Cooperative Extension System
"Greenhouse Production of Poinsettias"
bu Kessler
Good luck and good gardening! the "Hillbilly Gardener" |
