This year's order of Paperwhites came with the advice to make a 5% solution of alcohol (drinking and rubbing both work; the latter is much cheaper!) in water, and use that once the stems are 1-2" high to prevent legginess. I'm willing to try but want to be sure I'm mixing it right (since too much alcohol is bad for paperwhites as well as people).

I am using 70% rubbing alcohol and I want 16 oz. of 5% alcohol. I think I do the math like this:

.7x = .05 * 16
x = (.05 * 16) / .7 = 1.14

So I need a little over 1 oz of rubbing alcohol (approximately 2 Tablespoons plus another 1/4 teaspoon), plus enough water to make 16 oz.

Is that right? And has this worked for anyone else?

Here is the research link (thanks to @kevinsky): Ginning up a better paperwhite narcissus

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    Legginess is caused by low light. I am at a loss to understand how alcohol will help. – kevinsky Oct 23 '15 at 19:01
  • "Researchers at the Flowerbulb Research Program at Cornell University have come up with an unusual solution to this top heavy problem: Alcohol...the plants reach a height of 1/3 to 1/2 their normally expected growth, but the flowers remain normal size and last just as long." – kajaco Oct 23 '15 at 19:05
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    The original announcement is here impact.cals.cornell.edu/project/… and dates from 2006. I am surprised I have not heard of it. Upvote for this question – kevinsky Oct 23 '15 at 19:09
  • Thanks for the link! I notice it doesn't specifically mention the use of isopropanol (found in rubbing alcohol), but that's what I'm going to try. No way am I pouring ethanol on plants! – kajaco Oct 23 '15 at 19:52
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    @Sue, my results were that it's not worth the trouble. First, the presence of the isopropyl does not prevent algae growth. If I use plain water, I can just change it every few days, but with this mixture that seemed wasteful. Second, either the growth was way too stunted, or not stunted at all. So I don't think I'll do it again. – kajaco Apr 21 '16 at 18:20

The paper refers to ethanol, and not isopropyl alchohol which is a larger molecule and also toxic to humans. There are also differences in their effects on living tissue which is why isoproply alcohol is used as a skin preparation rather then ethanol. It may therefore have different effects on the roots from ethanol.

Since the authors of the paper ( http://horttech.ashspublications.org/content/16/2/294.full.pdf) have only tested ethanol, and do not know the mechanism of action, then you're conducting a different experiment. It's unfortunate that their paper uses the word alcohol in the title.

As for the math, if you dilute it 50% 4 times, you'll reach a final concentration of 4.35% which is close enough to their working range, and easy to do for experimentation.

Edit: I found another website that also claims isopropyl alcohol worked just as well. It's unclear if the claim is just being repeated, or if it's based on experience.


Tippling Tips for Paperwhites . . .

To get a 5% solution from a 40% distilled spirit like gin, vodka, whiskey, rum, or tequila, add 1 part of the booze to 7 parts of water – this is an 8-fold dilution, yielding 5% alcohol.

Rubbing alcohol (isopropyl alcohol) works just as well. It is usually 70% alcohol when purchased, so use 1 part rubbing alcohol to 10 or 11 parts water.

Do not use beer or wine, as the sugars in them will cause problems.

As with humans, paperwhites can suffer alcohol overdoses. Do not give them more than 10% alcohol.

It's thought that water stress is differentially affecting stem and leaf growth, but does not affect the flowers.

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  • Good work to find the original paper! – kevinsky Feb 6 '16 at 13:43
  • As I stated in the original question, the company selling the bulbs indicated that isopropyl will also work. Yes, I see that the original research did not cover that. I am not trying to reproduce the original research. As I further stated, ethanol is more expensive than I care to give flowers; I have better uses for it (me). Your dilution method may very well work, but it seems inefficiently repetitive. – kajaco Apr 21 '16 at 18:14
  • It's the simplest way to do an 8 fold dilution. But if you have more precise equipment, then go for it. – Graham Chiu Apr 21 '16 at 21:19
  • A set of measuring spoons and a 2-cup measuring cup seemed sufficient. Most kitchens have that, or close enough. – kajaco May 11 '16 at 17:51

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