If the pH is too high, would you use cold coffee to lower it, or is that going to harm the plant?
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@Reefers Watering with cold coffee
- Thread starterpotpimp
- Start dateJul 17, 2010
potpimp
Sector 5 Moderator
I’ve been on here long enough to hear it all… “I piss on my plants”, “my cat pisses on my plants”, etc. Most of it - and most of what you read on this forum - is BS, tales passed from one noob to the next. Uncle Ben refers to these as “snake oil and rocket fuel”. However, I recently read on a forum for master gardeners about using cold coffee on tomatoes. There was no science given but it sounded reasonable so I tried it on my tomatoes… and on a couple of my pot plants. While it is impossible to quantify the results, it does appear that it may have had some beneficial results. I used the cold coffee several times over the course of a week.
Now for the good part. I decided to check the pH of the residual of yesterdays coffee. But I needed a standard to go by so I checked my tap water first: 7.5. Then I poured the cold coffee into a glass and tested it: 5.5! That was interesting, a perfectly pH balanced amendment for our favorite plant.
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good to meet you bro Merry ChristmasTried and true. I use coffee or fruit juice (apple or oj) as my go to ph down. Both have an average ph of 4.8-5 out of the jug. Just like any ph down it depends on the water you start with. If you water is hard and high ph you will need more ph down. Even if using phosphoric acid. If you are close to your target ph and just a little high use very little.
Don’t forget to test your run off after you water to see what it comes out as. 
If you have hard and high ph measure with a shot glass per gallon. If you are close use a 1/2 teaspoon to measure, or a dosing syringe to not over do it. I first started using coffee is a pH down on my aquariums. The fish I needed to breed would not spawn unless the pH got down below 6. I couldn’t prove it but I think the caffeine helped amp them up too. Anyway it will not hurt your plants or your fish to do old coffee. And to use juice on your plants (not fish).
Do not pour either one right onto your soil by the way. I would say both need to be diluted into a mixing jug of water. Also, the nice thing about fruit juice is it’s loaded with sugars. It fires up your microbes just like molasses if you do any living soil in the grow. If you’re using bottled nutrients, skip the fruit juice. You’ll just end up with a bunch of bugs on your sugary soil afterwards.
Coffee grounds once the water has been ran through the pot have a neutral pH. But fresh coffee grounds not yet brewed make a great dry acidifying soil amendment if you have a garden with high pH. A rotten bag of citrus does this too, especially if you soak it in a bucket a day after you smash em. The fresh new coffee and fruit both have a very low pH just like the cold coffee in the pot. A couple cans of Folgers coffee from Costco goes a long way to fight a high pH raised bed.
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Thank you all for sharing your experience and insights.
Maybe I need to add some red wigglers, too.
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@Reefers they keep soil loose and help balance bacteria. it’s always a war going down in wide awake living soil. i rarely test ph except for water or organics going in. plus, over water you’ll know it. they’ll head to the top to keep from drowning. embarrass the hec out of you, don’t worry they won’t tell no body. they also have worm castings for faster growing strains and auto flowers.
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Ive been raising some of those in my used potting soil, to try to “rejuvenate” it. And to have worms to include in my grow. I just started my first flower run using them.
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Yes you are right @CurrDogg420 i can go anytime in my outside garden and always dig them up holeing garden but its always been like that here
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And for anyone that has never used them you have to turn them out on top of soil if you burry them they it will smother them to death it will kill them
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Well hopefully I didn’t kill them. I imagine that’s probably more of an issue if you’re using plastic pots or buckets. In my case Im using 20 gallon fabric pots, and I know my roots get plenty of air in these, so I think I’m ok.
The red wigglers only work the 6-8” of the soil surface. In the fabric pot, the sides count as a soil surface, so that’s yet another advantage to them in my estimation.
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I think they’re the same, Wikipedia lists them both as nicknames for Eisenia fetida
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That’s what I was thinking. Thanks for tips
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@CurrDogg420 
Worm are funny when you’re high. they move and consume soil then poke one end out the soil and see how sunny it is and test the humidity. Heat or Rain they’re on guard for, so squirt them with water they skeediddle fast like they fled
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When I was in college (back before they invented electricity), a friend taught me how to catch worms. They come out of the ground at night to mate on the top of the soil. You take a flashlight and shine it and when you see one you make sure not to shine the light directly in them or they’ll dive back underground quicker than you can imagine. Then you grab them and pull because they’re sure to have a bit still in the ground and you’ll be amazed at how strongly they can pull out of your hand, especially since they can be slippery. Once you practice up a bit, though, you can get a lot of them in a very short time. Usually around midnight is best. I’ll have to put the headlamp on and see if there are any around since it was pretty warm here today at 65 degrees. The wife will think I’m crazy. “Watcha doin’ out there?” “Catching earthworms.” “That’s nice. My sister warned me you were nuts.” “Yes dear.”
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That’s what I do to geather for fishing and best time right after it rains or spray ground with garden hose
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@Daddy1971 those three worms race around the bucket. don’t bet on the inside one. he’s really not ahead Ha!
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Get a bottle of PH UP, easy and organic.
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