Conditioning and processing: the bench work nobody photographs
Conditioning is the least glamorous and most consequential hours in the week. Almost everything that goes wrong with a flower on the wedding day was decided here, three days earlier.
The Florist Heaven desk / Chapter 5 of 5
The thing you are actually fighting
A cut stem takes up water through its vascular tissue. Anything that blocks that tissue stops the flower drinking, and a flower that cannot drink is finished whatever else you do for it. Most conditioning procedure is aimed at that one failure.
Extension guidance identifies microbial growth as a principal cause: microorganisms and the substances they produce plug the xylem, the water conducting tissue, and it reports a strong inverse relationship between the number of microbes in the water and how long cut flowers last.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
That reframes bucket washing from housekeeping into the main event. A dirty bucket is not untidy, it is an inoculation.
Sanitation, which is the actual job
The published procedure is to wash buckets with a low suds biodegradable detergent, rinse in clean water, and give a final rinse with a dilute bleach solution, ideally every time the bucket is used. It also advises disinfecting cutting tools frequently, at least twice a day, and notes that dull tools crush stems and reduce water uptake.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
On keeping the water itself clean, the same guidance notes that regular household bleach is short lived in solution, on the order of four hours, while commercially available slow release chlorine tablets last about two to three days. It advises replacing solution before it goes cloudy, because cloudiness indicates a high microbe count.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
The four hour figure is the useful one to internalise. A bucket you treated in the morning is untreated by lunchtime, which changes how you plan a long processing session.
Stripping and cutting
Foliage below the waterline should be removed, because submerged foliage decays and encourages bacterial growth. On the cut itself, the guidance notes that a slanted cut keeps stems from lying flat against the bucket bottom and increases water uptake.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
For a florist, this is the step where receiving differs from harvesting. You are cutting a stem that was already cut, possibly days ago, and the cut end has had time to seal and to collect whatever it stood in. Recutting is not a ritual: it is opening a functioning surface again.
It is also the step where the earlier arithmetic bites, because processing is where you find out how many stems in that box you can actually design with.
Ordering for loss, and how to measure your own loss rate rather than guess at it.
Read the stem count chapterWater, temperature, and what the solutions do
Acidified water is recommended: the guidance states the water should be acidified to a pH of about 3.0 to 5.5, on the basis that research shows flowers absorb more water in acidic solutions than at higher pH. It notes that how much acidifier is needed depends on the alkalinity of your own water supply, which is worth testing.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
It distinguishes the product types by what they contain and what they are for. Hydrating solutions are warm water, given as around 110F, with a biocide and an acidifier and a wetting agent, used briefly right after cutting to restore turgor. Holding solutions add a carbohydrate source, which is sugar, to encourage buds to open and extend longevity, and are used for longer afterwards.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
Two things in that are easy to miss. The first is that warm water rather than cold is specified for hydration, which is counterintuitive next to everything else about keeping flowers cold. The second is that these are different products for different moments, so using one where the other belongs is not a small substitution.
The guidance also cautions that not every flower responds the same way, advising you to test a treatment on a few stems before committing a whole delivery, because some species show phytotoxicity. It reports trial results where certain material lasted longest in plain water and had its vase life reduced by treatment solutions.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
That last point is the most useful correction to the way this subject is usually written. Postharvest solutions are not universally good; they are formulated for situations, and one of the published results is a flower that did better without them.
Ethylene, the invisible one
Ethylene is described as a colourless and odourless plant hormone that drives ageing, produced by the flowers themselves as they age and also by ripening fruit and vegetables, exhaust fumes, industrial and tobacco smoke, and micro organisms. The direct handling instruction given is to avoid storing flowers with fruit and vegetables.
UMass Amherst Center for Agriculture, Food, and the Environment, Harvesting and Handling Cut Flowers. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.
The reason this matters more in a small studio than in a large one is that the cooler is often the only cold space on the premises, and the temptation to keep anything else in it is obvious. The instruction is easy to follow once you know the mechanism and impossible to guess without it, because there is nothing to see or smell.
Where this guidance comes from
As in the cold storage chapter, the source here is extension material written for growers harvesting their own crop. The physiology and the sanitation transfer directly to a florist processing bought stems. The harvest specific parts, including when to cut and how to grade in the field, describe a job you are not doing. Your supplier and your own records are the better authority on the material you actually receive.
Questions this chapter answers
- How do florists condition flowers?
- Clean and disinfect buckets and tools, remove foliage that would sit below the waterline, cut the stem to open a working surface, and stand the stems in clean acidified water with a biocide. Published extension guidance specifies a pH around 3.0 to 5.5, warm water around 110F for hydrating solutions, and warns that household bleach loses effectiveness in about four hours. The source is linked in the chapter.
Sources
Every source below was read before it was cited. Where this chapter states a fact it did not derive, it points here.
- 01Harvesting and Handling Cut FlowersUMass Amherst Center for Agriculture, Food, and the Environment. Extension guidance on harvest stage, bucket sanitation, and the microbial cause of blocked stems. Written for growers in the northeastern United States, so treat the crop timing as regional.