Greenhouse Management: How can shipping put plants at risk?
Paul Pilon: A lot of things can go wrong during shipping. Many transport vehicles often aren’t temperature controlled — there’s high humidity, lower light and the length of time a plant is in that environment varies. A plant could be there anywhere from one day to three or four days, possibly even longer. In some instances, plants are harvested a day or a two before they’re loaded onto a truck adding onto the potential time shipping issues can arise. During this time, plants are not in their natural growing environments, so they are being set up for shipping stresses like ethylene release or diseases such as Botrytis.
GM: How can using a PGR help?
PP: When they are used during production, it not only results in a more compact, aesthetically pleasing plant, but PGRs can also help improve shelf life. Plants that have been treated with PGRs typically have thicker stems and thicker cell walls, so they are going to be less prone to some of these shipping issues. I often see treated plants holding up for almost two weeks longer than they would otherwise. This is especially important in the spring when sales can be halted due to cold, wet weather. OHP has Pac O, Cycocel and B-Nine WSG in its portfolio.
GM: How can wetting agents help address some of these problems?
PP: Wetting agents are compounds that help the growing mix hold onto moisture better, so it lengthens the time between irrigation cycles. Some growers are adding wetting agents to their irrigation to help them maximize their watering practices. The wetting agent OHP offers is Suffusion. During production, wetting agents typically last six to eight weeks and their efficacy lessens over time. It’s helpful to add a wetting agent just prior to shipping to replenish the soil and bring it back up to peak efficacy. The plants will then be at optimal moisture during shipping so they won’t dry out and also helps irrigation management at retail locations. Wetting agents don’t have to be applied the day of shipping, I like to apply them a week or so before to allow them to settle in an reach their full potential prior to shipping.
GM: How can fungicides help?
PP: Growers should apply fungicides preventatively before shipping. It’s important for the fungicide to be there to protect plants before they are placed in adverse conditions during shipping. We have a fungicide called Astun, which is a very good product for growers to apply a day or two before shipping to lessen the occurrence of Botrytis during transit. Last April, I did a shipping trial with Astun on annuals and I evaluated disease development and plant quality prior to and again when unboxing them. Treated plants either had no Botrytis or significantly less vs. untreated plants. The other interesting observation was that on certain crops, there were less stress symptoms. With geraniums, they commonly turn yellow when left in a box during shipping, it was very apparent that plants treated with Astun had significantly less yellowing. We are looking into why this occurs and for other practical applications for growers to use Astun.