Is it me or do florists not understand geometry?

[DaveC426913]

TL;DR Summary

Their logic for cutting stems at an angle seems pretty "sus"

Saw this on "Who Wants to Be a Millionaire" which, of course, I'd never trust on its own, so I verified:

It is common practice to cut flower stems at an angle, but I never thought to confirm why. I assumed it had something to do with cutting across the grain like one does with meat.

Apparently not.


"The first step in extending the life of your flowers is to individually cut each stem on a 45-degree angle. The reason for the angled cut is to increase the surface area, allowing the flowers to absorb more water."

I think they're whistlin' dixie.

Plant stems are basically bundles of vertical tubes, comparable to a bundle of straws.
Bundling some straws with rubber bands, and then cutting them at an angle does not increase their through-put/uptake.

The area of the cut surface is irrelevant; the relevant area is the cross-section of the stem perpendicular to the flow.

How can I turn this industry-wide ignorance into a million dollar idea?

 

[DaveC426913]

OK, a little more research turns up this:

https://shop.bloomon.co.uk/blogs/fl...you-need-to-cut-your-flower-stalks-diagonally

"By cutting a few inches from the bottom with a sharp knife, you make sure that the flowers can take in as much water as possible. That’s all very true, but it’s a fable that cutting at a diagonally enables flowers to take in even more water. [Wait. That's a contradiction. How can it be a true fable?]

Take a straw as an example, [ ] you can’t drink more when you cut it diagonally at the bottom.

Ok sure, so why then? Well, the reason why a diagonal surface is better for the stalk, is that it’s the simplest and most precise angle to cut. Also with using a sharp knife, you get a smooth surface, making it more difficult for bacteria and fungi to find a breeding ground. Making us come to the second reason why cutting with a knife is better than using scissors: it’s way easier."OK, so not universal ignorance (just national TV-level ignorance).How can I turn this wide-spread-but-not-universal ignorance into a half million dollar idea?

 

[TeethWhitener]

[Wait. That's a contradiction. How can it be a true fable?]

The true part is that cutting the stem allows the flower to take up more water, since it eliminates the part on the bottom that’s already been cut and is possibly dried out. The fable is apparently the diagonal cutting. But I always cut flowers diagonally with scissors, so apparently I’m just a Neanderthal.

 

[phinds]

How can I turn this wide-spread-but-not-universal ignorance into a half million dollar idea?

Advertise the RONCO PRECISION FLOWER STALK CUTTER that is GUARANTEED to cut the stem at a very precise 48.3 degree angle which has been SCIENTIFICALLY PROVEN to maximize water flow up the stem. Only $29.95, and we add in FREE a pair of gardening gloves.

BUT WAIT ... if you order IN THE NEXT 3 MINUTES we'll DOUBLE your order. Just pay a small extra handling fee.

 

[DaveC426913]

The true part is that cutting the stem allows the flower to take up more water, since it eliminates the part on the bottom that’s already been cut and is possibly dried out. The fable is apparently the diagonal cutting. But I always cut flowers diagonally with scissors, so apparently I’m just a Neanderthal.

Yes. No question that flowers do need to be cut.

I knew you want to get them into water quickly, but I always thought it was because, once the stems draw up air, they can't be primed again (just like a siphon). I did not know plants can "heal" the cut in just minutes.

I knew that you want a clean cut, and a knife does that better than scissors _{...you Neanderthal.}

 

[berkeman]

I think I know the real physics reason, but it would depend on whether the stems can reach the bottom of the vase that they are put into...

 

[BillTre]

I have heard this before somewhere.
This much makes sense to me.
A clean cut on the bottom of the stem will allow the stem to take up more water.
The opposite would be to crush the outer surfaces of the stem together until it is pinched off.
In the second case, the micro- or just bigger then micro- channels through which the water would enter the plant remains (cut-off flower) would be crushed together leaving little or no opening for the water to enter the ascending channels. In this case the flower would be expected to dry out rapidly.
The alternative would be to ensure the ends of the channels (basically made of delicate cellular products, on a very small scale) remain open so water can freely enter. Their delicacy can be gauged by how easy it is to crush the flower's stem.

Comparison of cutting methods (this is a lot like doing histology, preserving biological material and (usually) slicing it up to look at under a microscope, without messing up it's microscopic structure, something I have done a lot of):
Crush till broken: no good, channels crushed closed
cut with scissors: scissors can produce some crushing locally before the cut happens.
Cut with blade (normal histological method); should not crush unless you are cutting by pushing down on something.
Cut with blade at an angle: Cutting at an angle could allow easier cut without pushing down on something. It would be like whittling the end of a stick to a point by countering the force of the blade by keeping it from pulling the stem away from you. I would guess this method would result in the most open channels, most frequently.

Testing for open channels and water transportation:
There are experiments for kids involving celery and food coloring in water (actual childhood experience).
Celery have very large channel going up the outside of their stems in which the food coloring can be distinguished by the naked eye.

You could test:

• break vs. cut
• crush vs. scissors vs. blade vs. angled blade

If you want to try it on an actual flower, look for a kind of flower where the veins could be easily seen on the outside of the stem

 

[jim mcnamara]

Botany 101 - get a bunch of fresh white carnations, 5-6 stems is enough. Do the food coloring experiment with each stem cut to the same length with a different angle from say, 90 deg to ~30deg. Put the stems in the dye solution and time how long it takes for the dye to show up in the petals...

https://www.msichicago.org/science-at-home/hands-on-science/color-changing-carnations/

 

[berkeman]

Botany 101 - get a bunch of fresh white carnations, 5-6 stems is enough. Do the food coloring experiment with each stem cut to the same length with a different angle from say, 90 deg to ~30deg. Put the stems in the dye solution and time how long it takes for the dye to show up in the petals...

https://www.msichicago.org/science-at-home/hands-on-science/color-changing-carnations/

Can I cheat off of your paper? What happens?

 

[jim mcnamara]

Dye or food coloring moves up the stem and you can see the veins turn the color of the dye. The times are not going to be significantly different because what matters on transpiration rates for a stem like that is a very clean, sharp cut that does not damage the vessel elements (water conducting cells) in the stem. And a constant stem length.

Works for some kinds fresh food items -ex:
asparagus -- cleanly trim the stem bottom off, put them in water, like a flower bouquet. No refrigeration required.

 

[Astronuc]

Works for some kinds fresh food items -ex:
asparagus -- cleanly trim the stem bottom off, put them in water, like a flower bouquet. No refrigeration required.

Celery is often recommended, or it was when I did this experiment in the 1960s. I recall it from a How and Why Wonder book on experiments one can perform at home.

 

[jim mcnamara]

I had a 4 book set of How and Why. Celery experiment was in there too, I think because it was more available back in 1955 than other choices.

 

[Tom.G]

Summary:: Their logic for cutting stems at an angle seems pretty "sus"

It is common practice to cut flower stems at an angle, but I never thought to confirm why.

Try this experiment.

1. Obtain a drinking straw and a container of your preferred beverage.
2. Take a sip through the straw as you normally would.
3. Push the straw down to perpendicularly contact the bottom of the container and take another sip.
4. Cut the bottom of the straw at an angle, such as 45°.
   • Repeat step 3.
5. Report results.

 

[DaveC426913]

Try this experiment

Yeah, but that's not what the industry "wisdom" claims.

 

[hutchphd]

Yeah, but that's not what the industry "wisdom" claims.

It looks to me like industry "wisdom" has got you covered. Don't mess with a florist.
https://www.foxglovesflowers.com/faqs/why-should-i-re-cut-my-stems-at-an-angle/

It increases the surface area of the stems and allows for better water absorption. This technique also prevents stems from sitting flat against the bottom of the vase which can trap air and cause further blockages.

.

 

[DaveC426913]

Yes, some get it right. Many seem to think there is a direct correlation between increased surface area and greater water uptake. Not so.

 

[hutchphd]

Yes, some get it right. Many seem to think there is a direct correlation between increased surface area and greater water uptake. Not so.

Certainly true for the fresh cut stem. However if some sort of membrane (or lipid by-layer or other fancy thing) were to form at the interface and osmosis across that membrane were a rate-limiting step in the diffusion, then they would also be correct. Might be true for stems after a while.

 

[Snowman48]

Cut table flower stems at an angle because yer mom said so and then yer wife said so. Battles should be selected carefully.

 

[gmax137]

This technique also prevents stems from sitting flat against the bottom of the vase which can trap air and cause further blockages.

This is what I always thought.

 

[missylulu]

Cutting at an angle could assist in water take up as the stalks will sit on the point and the rest of the cut will sit off the bottom of the vase allowing the cut surface easier access to the water whereas if you cut the stalks straight across the stem it could sit flat against the bottom of the vase impeding water uptake (especially once the base of the vase gets a bit dirty/murky). It probably doesn't make much difference but if it doesn't why not err on the side of allowing easier access to the water of a greater surface area of the cut?

 

[DaveC426913]

Cutting at an angle could assist in water take up as the stalks will sit on the point and the rest of the cut will sit off the bottom of the vase allowing the cut surface easier access to the water whereas if you cut the stalks straight across the stem it could sit flat against the bottom of the vase impeding water uptake (especially once the base of the vase gets a bit dirty/murky). It probably doesn't make much difference but if it doesn't why not err on the side of allowing easier access to the water of a greater surface area of the cut?

Yes. The topic isn't about whether or not to cut the stems at an angle, the topic is what the general wisdom is in the florist industry about why one cuts it at an angle.

Many seem to be under a misapprehension..

 

[Tom.G]

...about why one cuts it at an angle.

Many seem to be under a misapprehension..

Or perhaps they don't care to 'explain' to Joe Six-Pack, who is buy'n flowers fer his main squeeze.

 

[DaveC426913]

The reason I raised this issue is because it was a question on 'Who Wants to be a Millionaire' - a nationally syndicated show lasting 17 seasons with 6 million viewers. It behooves them to get heir facts straight.

 

[hutchphd]

I think you should get the million.
They said because the water would get in better because of the area?

 

[DaveC426913]

I think you should get the million.
They said because the water would get in better because of the area?

Not quite. The question was more (paraphrased)

'To increase water uptake, one should cut flower stems...'

- with a chainsaw
- with scissors
- with a dull knife
- at an angle

 

[sarracen]

TL;DR Summary: Their logic for cutting stems at an angle seems pretty "sus"

Saw this on "Who Wants to Be a Millionaire" which, of course, I'd never trust on its own, so I verified:

It is common practice to cut flower stems at an angle, but I never thought to confirm why. I assumed it had something to do with cutting across the grain like one does with meat.

Apparently not.


"The first step in extending the life of your flowers is to individually cut each stem on a 45-degree angle. The reason for the angled cut is to increase the surface area, allowing the flowers to absorb more water."

I think they're whistlin' dixie.

Plant stems are basically bundles of vertical tubes, comparable to a bundle of straws.
Bundling some straws with rubber bands, and then cutting them at an angle does not increase their through-put/uptake.

The area of the cut surface is irrelevant; the relevant area is the cross-section of the stem perpendicular to the flow.

How can I turn this industry-wide ignorance into a million dollar idea?

I will agree there is much misinformation about flower care, but you are buying in to some inaccuracies.

There is are at least several reasons for cutting flower stems on an angle.
First, cutting the stems opens up the xylem to allow for water and nutrients to flow to the foliage and flowers. After harvest the "pumps" in the terminal ends are still working, trying to draw water up. As the stems dry those vessels are sealed by the suction...just like sucking on a straw with your finger over the opposite end. Recutting allows the water to flow again, bringing nutrients to the flowers and helping them open.

Second, having the stems cut at angle isn't really a big deal for consumers because most of the flower stems don't reach all the way to the bottom of a vase. From a professional point of view the angle doesn't have to be 45°. Just about any angle will do. The point is that flower stems don't sit flat in a bucket blocking water flow.
Also, as flowers mature there is bacteria that can grow in the water and as these are drawn up into the stem they will clog the opening, shortening the life of the flowers. That's why florists add preservatives that include nutrients and bactericides.

Side note, any clippers or scissors used for cutting flowers must be very sharp to prevent crushing the xylem. Some florists prefer knives, but the technique takes practice and regularly leads to cut fingers, though the cuts are much cleaner. One reason for that 45° angle has more to do with the physics of cutting rather than the physics of water absorption. An angle of 45° is easier to pull a knife blade through than a lower angle.

 

[DaveC426913]

...the angle doesn't have to be 45°. Just about any angle will do. The point is that flower stems don't sit flat in a bucket blocking water flow.

Thanks!

This is the only explanation I've seen so far that makes sense.I use a double-walled cup with a straw to drink my pop* with ice, and it is quite common to get the straw stuck to the bottom of the cup, making it much more difficult to draw liquid up by suction.

* soda

 

[JT Smith]

Then angled cut is prettier.

 

[sarracen]

Then angled cut is prettier.

Seriously, in 50 years in the flower business no customer has ever even mentioned the angle of the cuts, especially considering the stunning beauty of the designs we created!lol
What they have mentioned besides that is the length of time our flowers lasted. Between proper post-harvest care, professional treatment and proper use of floral preservatives, no one cares about the angle. I suppose in an OCD world every stem would have to be precise...