A Moving Target

Growers know it – postharvest success is a moving target! Last year around this time, Jon Felly of the Bouquet Connection in Madison, Wisconsin, sent me photos of terrific cut caryopteris. When I asked how he achieved such great looking stems, he gave this reply: “I wish I could say I had a magic formula, but I don’t.  It’s just the nature of the plant. As with all my production at the farm we spray Hydroflor 100 (a Floralife product) from a 2-liter pop bottle with a Windex pump directly on the cut ends, and then put them directly into buckets with well water. When they arrive back at the building they transfer all my stuff into Pokon & Chrysal Professional #2 in my sterile water.”
    
Jon’s methods may deviate from the listed instructions on the bottles of both products, but it’s hard to argue with success. When it comes to choosing the correct solution, focus on the three major cut flower problems.

Water balance disturbance: Caused by blocked vascular systems due to microorganisms, organic materials or air bubbles in solution. Water balance problems result in limp flowers and foliage. If you ship dry-pack, remember to tell clients how important it is to get wilt-sensitive blooms processed. It is not unusual for a wholesaler or bouquet maker to rotate flowers dry 2-6 days after receiving so don’t be afraid to push the point.

Disturbed plant growth regulator balance (PGR’s): Harvesting causes a release of stress and aging agents, not to mention the lack of PGR’s. Symptoms include ethylene development (aging hormone), leaf yellowing, stem stretching, phototropism, and geotropism (where stems bend away from light and gravity). This category is all about hormone rebalancing!

Disturbed Nutrient Balance: Flowers stop photosynthesizing once harvested so they need nutrients supplied to develop shape, color, fragrance and turgidity.

Target Practice

Want to improve vase performance? Pick the right solution(s) to protect your crops. In a perfect world, you could customize treatments to specific crops, but real world time constraints push us to simplify the various treatments used.

Crops with water balance problems like bupleurum, corn flowers, lobelia, caryopteris, roses, gerberas, bouvardia and ornamental foliages fare best with a hydration solution as first drink. Hydration solutions are all about boosting flow. They contain no sugar because sugar at the harvest stage often impedes flow. Several commercial products are available and because they have different combinations of biocides and acidifiers, it is important to run tests to see which formula work best for your crops.
    
Can’t get everything harvested before 11 a.m.? Try using OVB hydration solution – growers swear it works even if the temperature is over 100F. Different products use different formulations, but all hydration solutions lower the pH, have germicides to keep pollution in check and contain no sugar. A few commercial hydration products are Floralife’s Hydroflor, Hydraplus from Syndicate Sales and Chrysal’s OVB and Professional #1.

Crops suffering from an imbalance of plant growth regulators are likely to have symptoms of premature aging, stem stretching and premature foliage yellowing. Ethylene is probably the best known plant growth regulator (PGR). Volumes have been written on ethylene and treating against ethylene damage. Floralife’s ethylene protector works as a gaseous product that protects sensitive flower types. If you grow flowers in Texas, Oregon, California, Michigan, Minneapolis, Florida, Colorado, Pennsylvania or Washington, your state EPA allows you to use a systemic treatment, silverthiosulfate (STS), available from Chrysal. Do follow the disposal directions. It is illegal to dump spent STS solutions directly into the sewer.
    
Other PGR’s include gibberellins and cytocinines. They control premature leaf yellowing. After harvest, the flower can’t produce growth regulators so blooms like tulips, solidaster, iris, lilies and alstroemeria greatly benefit from treatments that introduce PGR’s back into the vascular system. A recent article from the University of Florida, Gainesville, “Short Term Pulsing Improves Postharvest Leaf Quality of Cut Oriental Lilies”, compares different commercial products on the vase life and foliage quality of cut oriental lily varieties ‘Star Gazer’, ‘Acapulco’, ‘Kissproof’, ‘Noblesse.’ If interested, send me your e-address and I’ll email you a copy.
    
Finally, let’s consider nutrient imbalances. When you hear “nutrients”, think sugar. Sugar keeps leaves and petals turgid, colors vibrant and buds opening. All flower foods contain simple sugars. But don’t be too quick to grab the cheapest pail of powder off the shelf.  It’s not the best product for you.  It is too high in sugar to use in the first stages of handling. Instead, look for a low-sugar solution formulated specifically for wholesale processing and retail sales display. There are many low-sugar foods from which to choose: Floralife Commercial, Chrysal Professional #2, Aqua hold – all liquid concentrates. Measure when you start filling buckets!  Otherwise you are wasting money. Crops that do best processed directly into a low-sugar solution are lisianthus, stock and tight cut sunflowers.
    
If flower holding quality has been less than superb this summer, make a few comparison tests before every stem is harvested. Organize your notes and prepare new strategies for 2005.