Poinsettia “Toning” by Stacy Meyerink and Elissa Sutton

We began our Greenhouse Practical this weekend at the Spriet Family Greenhouse, our main focus for the weekend was tending to the 1000 poinsettias that we have been growing since the beginning of term.  We will be selling these poinsettia’s to raise Money for the Fanshawe Horticultural Technician Program and must ensure that each plant is “Toned” correctly to make sure that they are ready for a drastic change of environment, from the warm inviting environment of the greenhouse into household plants.  

The poinsettias have been in a photoinduction period, the process by which the poinsettia go through an extended dark period followed by a light period in order to start the coloring up process.  The photoinduction period ends on November 14^th at which the Poinsettia crop will be ready for sale.

It is time to start “Toning” the poinsettia’s, we reduce fertility by gradually reducing the fertilizer levels to a third of the original strength used for active growing.  To do this we decrease fertilizer timing as well as begin the process of leaching the media to remove any access salt in the media, EC levels will be checked every week to ensure that this process is occurring in the timetable needed.  At this time we will be changing fertilizer formulation to a 12-0-44 mix.  This Particular fertilizer will increase the poinsettia’s ability to deal with stressful situations that will occur when the plant is moved from one environment to another.

It is important to reduce the fertilizer levels in the soil prior to the end of the growing process to help the poinsettias keep longer and reduce any bract browning.  Before sale we will ensure that each cultivar is watered without a fertilizer solution to reduce these salt levels.  It is also important at this time that we reduce the temperature slightly, this will harden off the poinsettia’s and create more vibrant colouration of the bracts about 1 degree Celsius a day, the final temperature before shipping should be held at 16-17 degrees Celsius. 

When you see pollen you can ship the plant, not before.  One thing that is of utmost important is the fact that poinsettia’s are intolerant to any cold temperatures.  They must be wrapped prior to leaving the greenhouse and transported directly to the end location.  Do not leave them outside, do not leave them in the car unattended, keep them warm, anything exposure to 10 degree or below will cause plant damage.