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Poinsettia Tips :: by Ellen C. Wells
Published:5/1/2008
Start your growing season on the right foot
It’s nearly time to start this coming winter’s poinsettia crop. Are you prepared? We asked several poinsettia experts—Jack Williams from the Ecke Ranch, Dr. Allen Hammer from Dummen USA, and Harvey Lang from Syngenta Flowers—for tips on how growers should plan for poinsettia propagation and handle the critical first few weeks.
Before cuttings arrive
“Look at last year’s notes,” Allen says, “even before you start growing this year’s crop.” You’ll get a jump on handling similar issues that arise this year. Each year is different, but Allen says it never hurts to pull out the poinsettia manual to read up on recommended procedures.
Get ready for propagation by disinfecting benches and walkways. Harvey recommends using Greenshield, Physan 20, or other disinfectants. Cuttings are especially susceptible to pythium root rot brought into propagation area on dirty shoes and from other contaminated benches. Do what you can to protect the cuttings and prevent contamination.
“We really want to see cuttings out of the boxes as soon as possible,” Jack advises. “Have the media in pots or the filling machine ready to go. When the cuttings arrive, you can open the boxes and do whatever’s necessary to send the plants into the greenhouse as quickly as possible,” he says.
When cuttings arrive
Check the packing slips against your order as soon as you've taken the delivery. Logistics systems are good, Jack says, but it’s best to ensure you’ve gotten what you’ve ordered.
Jack also recommends having a veteran poinsettia handler open a few boxes and take a quick survey of the contents. Does the box feel warm inside? Is there an unusual odor that could be a sign of decay? “Don’t take problems into the greenhouse. Catch them before they get in there,” he advises.
If you have concerns, call the supplier immediately. Inform them you may have a problem. Jack says growers usually know within the first four days whether they’ll need replacements, and updating the supplier at ASAP gives them time to see if replacements will be available. Waiting several weeks to address the problem limits replacements and also throws off the production schedule.
Allen recommends unrooted cuttings be placed in a cooler overnight after they arrive. “It allows the cutting to get turgid,” he says, “and growers can use that time to plan their sticking for the next morning.”
Combating heat and light
Because rooted and unrooted cuttings can become dry, Harvey recommends applying CapSil, a wetting agent, at a rate of 2 to 4 oz. per 100 gal. the day after the poinsettias are potted or stuck. “This helps rehydrate the cutting and gets them out of a stressed stage,” Harvey says.
Growers receive poinsettia cuttings when conditions are hot and bright—not exactly ideal conditions for cuttings. Our three experts were unanimous in stressing the need to protect the young cuttings by using shading and misting.
“If you don’t have sufficient shade, it’s hard to hydrate the cuttings,” Harvey says. “You have to almost flood them with water, which leads to botrytis and erwinia soft rot.” He says too much light is a common problem, and he recommends providing shade to reduce light levels below 1500 f.c. This cuts back misting to proper levels, and overall reduces stress on the cutting. Keep a careful eye on the weather, light conditions, and mist levels for the first 10 days.
Pinching
For Allen, the most critical step in poinsettia propagation is pinching, and he’s found it’s the step growers most often delay. “When the roots reach the edge of the pot, you pinch them,” he says. This typically happens 10 to 14 days after potting for rooted cuttings and up to four weeks after for unrooted cuttings. “Even a five-day delay will show up in December as uneven branching,” he says.
Harvey has found that certain dark-leafed varieties don’t branch evenly after pinching. For those varieties, he recommends removing the first two to three upper leaves when pinching, making the lateral shoots branch more evenly.
Energy conservation
Poinsettia crops can require a good deal of energy. How can growers address this? “Early in the growing season is not the time to save energy,” Allen says. “”It’ll cost you more at the end of the crop. Growers are building up the plant at this time, and they’ll need to provide the optimum environment, even it if means turning on the heat on cool early-September nights.”
Jack says choosing the right genetics from the start can make a difference. Some varieties do very well grown in cooler temperatures, but they’ll need to be potted a week or two in advance to finish on time. They’ll even create a more durable product that travels and displays better at retail and in the home.