Stale unused coffee

Unused coffee, I'm pretty sure I can compost it without a problem? Is there a better use for it? Like, could it repel Garden pests or something?

A couple of days ago I was offered an opened can of coffee that had been left in the back of a cabinet for several years. I'm not a big coffee drinker, so I don't know how long coffee is good after it is opened but certainly it can't be good if it's several years old? Probably pre-covid? I took the can knowing that used coffee grounds are popular in compost, so I'm pretty sure that it would be fine.
But I got to thinking about it, and realized that there might be better uses for stale coffee.

It is the "Chock Full O Nuts" brand, if that makes any difference.

Hi Nancy,

I live in a big coffee-drinking household and we get through a lot. All of our spent grounds (once they have been used to make coffee) get composted straight in the heap, where they seem to do very well. We have picked up waste coffee from cafes too, as they often give away their grounds, but not so regularly.

It has been said that too much coffee in the compost will sour it (turn it acidic). I'm not sure how true that is and, certainly, it could be balanced out with some chalk/lime/wood ash (and our compost gets some the latter two).

I've also heard that slugs and snails don't like coffee grounds and will not crawl (slide?) over it if they can avoid doing so. I have tried to create rings of coffee grounds around sensitive plants but, to be honest, I've not noticed much of an effect.

A final thought is that it may be good for disguising plants for whom the pests discover by smell. Carrot root fly, for example, is famous for smelling out the carrots that it lays its larvae in and people often use a guild of aromatic plants, such as marigolds or garlic, alongside the carrots to discourage the fly. I wonder if coffee grounds in close proximity to carrots would help too?

Hi Nancy,
I once got a whole box full of expired coffee packets from a gas station down the road. It was a pain to open them all and keep the garbage from blowing away, but I simply used it as a soil amendment in the fall on my garden and sprinkled it around without bothering to add it to my compost pile.

There is a difference between unused coffee grounds and used coffee grounds as far as the PH goes... I just can't recall which is which right now. Anyone else know?

Sams club had offered some new brands and I bought Chock Full of nuts on a whim. ...

We keep stale unused coffee at our off grid cabin.  It seems okay when I brew it.

I am not a gourmet coffee drinker so that might make a difference.

Luke Mitchell wrote:

I've also heard that slugs and snails don't like coffee grounds and will not crawl (slide?) over it if they can avoid doing so. I have tried to create rings of coffee grounds around sensitive plants but, to be honest, I've not noticed much of an effect.

A final thought is that it may be good for disguising plants for whom the pests discover by smell. Carrot root fly, for example, is famous for smelling out the carrots that it lays its larvae in and people often use a guild of aromatic plants, such as marigolds or garlic, alongside the carrots to discourage the fly. I wonder if coffee grounds in close proximity to carrots would help too?

Ooo! Sounds like it could be used as a top dressing? Even if it doesn't help, it probably won't hurt.

Thankyou.

Matt McSpadden wrote:Hi Nancy,
I once got a whole box full of expired coffee packets from a gas station down the road. It was a pain to open them all and keep the garbage from blowing away, but I simply used it as a soil amendment in the fall on my garden and sprinkled it around without bothering to add it to my compost pile.

There is a difference between unused coffee grounds and used coffee grounds as far as the PH goes... I just can't recall which is which right now. Anyone else know?

Thank you. This is a container that was opened ( seal broken) and then forgotten in a cabinet. I would guess that since coffee is acidic, unused coffee probably leeches acidic pH?

Coffee grounds, when used as mulch, can clump and create a barrier. So if you have a lot, it's generally recommended to mix it well with another mulch source, or to use it in a thin layer.

What I like about coffee (or spent tea leaves) is that it's visually discreet, and it doesn't attract pests, so you can compost it straight in one's garden beds. I have limited compost space, so anything that goes straight to the garden is helpful, especially if I don't have to dig.

I've read studies indicating that it's not as miraculous as some sources indicate (for slugs, plant growth) and even that it can be detrimental to young seedlings in large amounts. Spent coffee grounds are less acidic than what common wisdom indicates (the acid part gets dissolved in water and that's what we drink) but new grounds might have a short term acidifying effect. But any source of organic material in soil is a good thing long term. And any organic material that stays as close as possible to home rather than going to a landfill is a good thing.

So I'd simply sprinkle it thinly around established plants/trees in places anywhere the soil might benefit from extra organic material, and doubly so if it's a plant that likes acid soil (it won't make much of a difference long term, but it won't hurt).

Summary article from a source I really trust: https://laidbackgardener.blog/2016/02/11/the-truth-about-coffee-grounds/

Since coffee grounds are a good substrate on which to grow mushrooms, and also excellent feed for black soldier flies...I would imagine that unused ground coffee might well work equally well.  One advantage for the mushrooms is that the grounds if they are fresh, are basically semi-sterilized by the brewing process and so are ready to inoculate....

If you’re feeling adventurous, you could try using the coffee as a natural pest repellent in the garden, as some insects dislike the smell of coffee grounds. If you still have a lot left, though, I think composting is the most practical option! Just make sure to mix it well with other compost materials to avoid clumping.

I guess you can give it a stir and a sniff to see how bad it is. Sometimes you can brew up sketchy coffee grounds and add hot chocolate fixings to make a sort of coca-mocha that's palatable. And then use the grounds on the garden.

My used coffee grounds either go into the compost, or get sprinkled around anything that likes an acidic soil - rhubarb, berries, tomatoes, and if you can grow them camellias - I'm sure there are more plants that like acidic conditions . . .

Makes a good winter de-icer for your steps or sidewalks. We use it after making coffee, but it would also work raw.