Coffee grounds on roses in pots --

[Kisal]

My friends keep telling me to put my used coffee grounds around my potted miniature roses. I know that coffee grounds are good for roses that are planted in the ground, but I'm not so sure about roses in pots. I'm concerned that the soil might become too acidic because of the closed environment of the pot, I.e. excess acidity couldn't dissipate into the surrounding soil.

Any advice would be welcome. TIA!

[Anonymous]

My friends keep telling me to put my used coffee grounds around my potted miniature roses. I know that coffee grounds are good for roses that are planted in the ground, but I'm not so sure about roses in pots. I'm concerned that the soil might become too acidic because of the closed environment of the pot, I.e. excess acidity couldn't dissipate into the surrounding soil.

Any advice would be welcome. TIA!

Are your friends using grounds in their pots? If not, WTH are they advising you to do it? If they are then they should show you their plants and you can judge from that.

Most of the coffee grounds acidity went into your stomach. Used grounds just are not that acidic.

What is good about coffee grounds is not the acidity but the friability and proteins, nitrogen, etc. they add to the soil as a (very) slow release fertilizer.
What is bad is that mold can grow on them so top of the soil is a bad idea. They need to be worked into and under the surface.

It is not much of a fertilizer or an agent to change pH but it will buffer and will add some nutrients.
And if you think about it, just how much change can a scoop of used grounds make? You don't (probably) have much room in the pot for more than 1 coffee pot's worth anyway!
...

Yes, I drink a lot of coffee and I do use the grounds just about everywhere from a potted "groundcover" rose( more or less a hybrid tea rose), the blueberries, tomatoes, ... compost bin.
In truth I have a bunch of grounds to use right now. I think I'll use them on the excuse for a hedge rose that Jackson and Perkins mislabels as "Simplicity" Rose. ... I've tried just about everything else.

Have Fun!

[Kisal]

Thank you sooooo much for answering my post! The truth is, only one of them really knows anything much about gardening, and he doesn't grow anything in containers, nor does he grow roses. The other person has houseplants, but her father grows miniature roses ... in the ground in California, which is quite a different scenario than I have here. Those are the reasons I hesitated to follow their advice.

I think I'll just put my coffee grounds on my compost pile!

[Anonymous]

Thank you ...
I think I'll just put my coffee grounds on my compost pile!

Your welcome. Posts with zero relies on the subject are terrible things. I hate it when that happens. It happens a lot to me ... tough &|R uninteresting questions isuppose.

And ... " He chose wisely. ", the knight nodded with approval. --Indiana Jones
( Please, nobody interpret|extrapolate that to I think of myself like a knight. The choice just reminded me of the movie because it sounds like a very wise choice, all things considered. )

I am just curious enough to ask: was (or is) there something wrong with the miniatures to invite such loving, albeit possibly misplaced, advice from your friends?
... Or is this one of those 'yea they are great but they could be better things' from friends?


...
For (others) reference, pH is a range. NO living thing lives at any specific pH. IMO, if that was true there would be no life on the planet.
There are "optimum" ranges but, really, one designated pH for a plant needs to be taken as a range around which the plant thrives. The chemistry of living organisms makes it so. When one gets down to the microscopic level, the range can narrow but it is still a range(any lurking microbiologist can speak up here).
Even measurement of pH is a range. There are some handy digital multimeters that can measure pH *of the surrounding soil* but they have ranges of accuracy and there are other factors which limit|control the accuracy. Move the probe two feet and one can get an entirely different reading. Move it another two inches and the reading might be exactly what the first was.
...
Anyway, point being that pH is just a target. Think of it like a bullseye target and one is using a bow & arrow. Getting close to center is great. Missing the target completely is bad.


Have Fun!

[Kisal]

No, there isn't anything really wrong with the roses. Some of the leaves are a bit yellowed, but they had spider mites. I've used Safer's Soap for that and am sure they'll be fine. I repotted them into larger pots about 3 weeks ago, and although only one is blooming at the moment, they are all showing healthy new growth.

I think my friends were just trying to be helpful. They're good folks, but I don't consider them to be especially "experienced" when it comes to growing miniature roses in pots. That's why I asked here, hoping to get some advice such as you provided about the range of pH and so on. I thank you again!