Fertilizing with Coffee?

[JanS]

I wouldn't use coffee grounds for orchids: coffee is acidic and some grounds can have a very low pH which orchids generally don't care for. On the other hand, the acidity is good for some other plants like azaleas, blueberries, etc. which can benefit from coffee grounds worked into the soil around them.

As far as the killing snails bit, a couple of years ago I had a huge problem with little snails that got into my orchid pots through some plant(s?) I bought and proceeded to devastate my collection. I read up scientific literature on the use of caffeine to kill snails and the dosing - which is so much higher than can be achieved with coffee itself that using coffee or spent grounds (which have even less caffeine) makes no sense. So I bought several bottles of No-Doze (the pharmacy cashier was giving me weird looks ), dissolved them to proper concentration, used a home-made centrifuge to spin out the chalk from the pills..and watered my most affected orchids with the liquid.

If it had any effect at all, it was minor and temporary (and expensive since I spent over $20 on No-Doz to get enough liquid for just a few pots). So my advice is - DON'T BOTHER! Even the scientific papers note that effects vary from 50-70%. If you have a snail problem and need 100% snail death (who doesn't?), watering your plants with a malathion (back on the US market) solution was the only answer that worked for me.

I did notice my caffenaited orchids shaking a bit uncontrolably after that treatment, though...

[DavidCampen]

Originally Posted by JanS

... I bought several bottles of No-Doze (the pharmacy cashier was giving me weird looks ), dissolved them to proper concentration, used a home-made centrifuge to spin out the chalk from the pills..and watered my most affected orchids with the liquid.

If it had any effect at all, it was minor and temporary (and expensive since I spent over $20 on No-Doz to get enough liquid for just a few pots). So my advice is - DON'T BOTHER! Even the scientific papers note that effects vary from 50-70%. If you have a snail problem and need 100% snail death (who doesn't?), watering your plants with a malathion (back on the US market) solution was the only answer that worked for me.

I did notice my caffenaited orchids shaking a bit uncontrolably after that treatment, though...

Really, you were using caffeine at 2% and saw no effect? I have to disagree, I am using 2% caffeine solution to kill bush snails and it is very effective. When I put a drop of the 2% caffeine solution on a bush snail there is an immediate effect; the snail falls on its side and extrudes its foot, in the morning and the next day the snail is exactly where it was the night before so presumably dead. To treat a plant, I saturate the potting media with the 2% caffeine solution applied from a spray bottle; a 6-7 inch pot requires most of a 500 ml spray bottle of caffeine solution.

I buy pure caffeine, $9 for 150 grams, from NutraBio:
NutraBio caffeine anhydrous USP.

Good to know about the malathion though. If the spot treating of single plants with 2% caffeine solution is not enough and I decide to treat all of my plants then I was going to use caffeine plus Sevin but perhaps instead I would try caffeine plus malathion.

---------- Post added at 10:58 AM ---------- Previous post was at 09:37 AM ----------

Even the scientific papers note that effects vary from 50-70%.

Is there more than 1 paper? The only one that I know of is this:
http://digitalcommons.unl.edu/cgi/vi...ne%20snails%22
It reports 90 - 100% mortality with 2% caffeine solution:
"To test whether caffeine solutions could be used to remove or kill large slugs that attack potted plants, we allowed Veronicella cubensis (Pfeiffer) to
bury themselves in the soil in the pots, and then thoroughly wetted the soil with a 2% caffeine solution. After 3.5 h, only 25% of the slugs remained in the soil; after 48 h, all slugs had left the soil and 92% were dead.
...
To test the effect of caffeine on snails, we treated mature orchid snails (Zonitoides arboreus (Say); about 3 mm in diameter) topically with caffeine solutions in Petri dishes ... and all snails treated with 0.5 or 2% caffeine were dead after 96 h (Fig. 2b).
...
We then carried out two greenhouse tests in which caffeine solutions were applied to the growing medium of potted orchids infested with Z. arboreus. In the first test, 1 and 2% solutions of caffeine were associated with 60 and 95% mortality, respectively (control mortality averaged 10%). In the second, larger test, a 2% solution of caffeine proved to be more effective in reducing the presence of snails than a solution of 0.195% metaldehyde, the commercial standard for orchid-snail treatment. Over 30 days, 5 snails were extracted from the medium treated with caffeine, whereas 43 and 35 snails were collected from media treated with water (control) and metaldehyde, respectively."