Coffee grounds on the garden?

What is your soil pH? If the soil is alkaline, coffee grounds can help with that, as well as adding a little nitrogen and organic matter. If the soil is acid, which is more likely in most of the UK, it will cause problems.

The acidity of USED coffee grounds is negligible with a PH closer to 7. Most of the acid goes into your coffee cup. Fresh coffee grounds have a higher concentration and can cause problems with the wrong plants, but there are those plants that love acid soil - camilias, rhododendrons, hollies, hydrangeas. These would look just lovely with fresh coffee grounds.

In my opinion, its one of those faddy things that appear occasionally, rather like chopping up banana skins and placing them on the soil around plants. Or the one about draping your rose bushes in banana skins because it did something or other, I can't even remember what it was supposed to help with now. Banana skins are a great addition to the compost heap though... Occasional addition of coffee grounds to the compost heap is fine, but not a daily dose of them in the compost, that's too much. If you want to sprinkle a few around the base of acid loving plants, that won't do any harm, but literally just a few; use a lot and it sets like concrete, forming an impenetrable mat.

I don't know if you've heard of James Wong - he does Gardener's Question Time on the radio occasionally, and I recall about 3 years ago, against the opinion of the other members on the panel at the time, he liberally applied coffee grounds to his houseplants. And then had the grace, when asked on the panel about a year later, to say he got it wrong and confessed they all died...

We human beings have a tendency, when hearing that a little of something does some good in some circumstances, to expand that and think an awful lot on absolutely everything will give even better results.

I only drink a cup or two a day but haven't got space for composting so anything free I can chuck on is a bonus.
I always read James Wong's Sunday column on the Guardian website & in a fairly recent one he said that coffee bushes produce a chemical that stops other plants encroaching on it's space. Seems reasonable?

Not just the coffee plant, but the seeds even more so - this is not uncommon in the horticultural world, many plants have a mild allelopathic effect in an effort to deter other plants from taking up space and nutrients nearby. Black walnut has quite an extreme allelopathic effect, but sometimes, the effect only works on certain other plants,

Given coffee grounds are simply ground up coffee seeds, then allelopathy might be a significant factor to consider - don't know if you've seen this article, if you're a follower of James Wong, you might have done, but its in the link below for you to check, you'll need to copy and paste into your browser

https://www.theguardian.com/lifeandstyle/2016/oct/23/coffee-grounds-are-not-good-for-plants-its-a-myth

And, if you only have a small garden, dumping grounds from two cups of coffee a day every day onto the soil is way too much... flush 'em down the loo instead, or put them into the household waste.

RE the pH of coffee grounds:
I was curious, and investigated that in the 80's--with dixie cups and pool supply pH paper! :) I was only able to test samples from six different sources. The infusions I made, with what standardization I could manage, varied from nearly clear to nearly "drinkable", with pH's varying from 6.5 to 5.0. When I got that last result, I thought to myself, "Who drinks this stuff?!"

Bamboo, going off topic but banana skins to start tomatoes ripening may be called a fad but it works. The gas it gives off is ethylene and another ripe tomato or even a ripe apple should work just as well though I haven't tried an apple. Its just that banana skins are easier to drape on the plant than a ripe tomato ...

Coffee grounds are great for composting. They replenish many other nutrients in the soil including nitrogen - the most important one. I know several people who collect used coffee grounds from Starbucks & other coffee shops who are too glad to get rid of them. Everybody wins.

Steragram - that's not what I was talking about - it was very definitely draping roses in banana skins - I really wish I could remember what it was supposed to do. Maybe treat black spot or some such nonsense... I never cease to be amazed by what people will believe....
Bananas are useful for their ethylene - I always put a ripe banana near unripe nectarines in hopes it'll help them to ripen.

Tug: you're right, the ph of the grounds does vary, quite widely in fact, from what I've read.

Have to say that, in terms of a definitive answer, I'm thinking James Wong's given us it. Yes coffee grounds are not that acidic & fairly high in nitrogen but they also contain other, as Bamboo points out, allelopathic chemicals that inhibit growth.
So not that great as a garden ingredient?!
Only place I can throw them now is on the pointless box bush in the corner that's annoyingly vigorous & takes up useful space😊

Do a little more research please. Otherwise you'll walk away with erroneous information. Let's try to prevent that: If your coffee grounds are composted, those chemicals become inert which is the whole point of composting. Then it's safe to use as a general compost. If you decide to use 'fresh' coffee grounds, those chemical only inhibit the growth of some plants for a short time.

'They do, however, contain allelopathic chemicals that can inhibit growth in certain susceptible plants. Once the coffee grounds fully decompose this is not a concern.'

https://www.melindamyers.com/articles/using-coffee-grounds-in-the-garden

Absolutely love your contribution Bathgate! That's why I said definitive. I'd question that chemicals become inert just by composting. Chemicals persist?

Sorry Bamboo - went off on one of my own. You said roses, I thought tomatoes. Severe case of brain softening and there appears to be no cure...

Steragram - too true... no cure for a lot of what ails us as we get older, it's that built in obsolescense factor, but I imagine the info about ethylene will be useful to someone or other anyway...