|
|
More news |
| Avoiding problems with Poinsettias | |
Plant roots are monitered every day. When plants are too wet, the best roots are found at the top of the soil zone. When too dry, the best roots are found at the bottom of the soil zone where moisture is readily available. The aim is to get an even distribution of roots throughout the soil strata. Young root tips should be white and covered with root hairs. Not all Poinsettia varieties have the same leaf size or rate of water usage, so ensure that only those varieties with similar characteristuics are planted next to one another. During early stages of development, irrigation is timed towards mid-day when the soil/root zone temperatures are increasing. The irrigation water acts to cool the soil and to keep the roots active. Once the plants begin to shade the soil from direct light, they can be irrigated first thing in the morning. When soil temperature rises above 25°C stress conditions begin to inhibit up-take of water. Good irrigation practice minimizes insect and disease damage to the plants. Scarid fly larvae thrive in compost with a high moisture content. Sub-irrigation systems that moisten all but the top 1-2cm of the soil effectively reduce the possibility for the larvae to hatch in the top strata of the soil. A good water balance also reduces the danger of attack by Phythium and Phytophthora pathogens. The ability of the plant to branch uniformly is a genetic characteristic. Day and night temperatures consistently above 25°C causes the break down of shoot development in some varieties. A soft pinch with leaf removal maximizes the opportunity for the plant to develop full branching. Stem breakage at the time of packing is partly genetically controlled. More horizontal branches grow this way in an attempt to find light. This should be discouraged by adequate spacing because it is these branches that break more easily. Calcium is essential in the developent of strong cells and branches. To develop strong colour and expansion of the bracts requires the right balance between temperature and light. At the start, high light conditions and warm days maximize bract colouration and expansion. As the bracts mature, both temperature and light are reduced to promote more intense coloration. The mean temperature for plant development id 18°C. As long as plant surfaces are kept dry the risk of Botrytis attack are greatly reduced. Jack Williams, Ecke Europe, “FlowerTech” Fax 0031 314 340515, www.HortiWorld.nl |
|