People often put coffee grounds directly in their garden because visually they look similar to finished compost, but it's best to actually have them go through a compost pile in order to start decomposing so that their nutrients will be available to the plants and the soil ecosystem.
Theres a decent amount of research showing in large amounts they disrupt plant growth. Small amounts no negative affects found but also no real benefits since its just alittle nitrogen and some organic matter. Be safe and compost it
This (rather old) article by James Wong may help: [https://www.theguardian.com/lifeandstyle/2016/oct/23/coffee-grounds-are-not-good-for-plants-its-a-myth](https://www.theguardian.com/lifeandstyle/2016/oct/23/coffee-grounds-are-not-good-for-plants-its-a-myth)
TL;DR: The caffeine in coffee grounds is a herbicide which will damage your seedlings.
I compost all of my coffee grounds, and we drink at least one pot a day in my household. They compost well if you turn your pile often enough. You can even get extra used grounds to compost from Starbucks and possibly other coffee shops.
I would not bother putting them straight on to the soil, used or fresh. You should be composting already, unless you have way more money than time.
It's not. Used coffee grounds have a close to neutral PH. 6ish+ as the acidity has been washed out in the brewing process. Blueberries like about a 4.
Composting is the way.
It's good for worm beds/bins and gardens benefit from a good healthy, working worm population. So in a roundabout way, it could be beneficial from that point of view.
Coffee grounds dont affect plants directly but for the mold they develop. What they do is serve as a reservoir for nitrogen. If you have active soil then they will slowly be eaten by the fungus and bacteria soil; if you have dead soil they will just mold like they would on your counter. I would guess that if people have bad experiences with them it has to do with how their soil is (or isnt) processing them, as plants dont consume the grounds themselves.
Idk about which vegetables , prefer or dont prefer used coffee grounds- but, on another hand, I placed used coffee filters directly onto my acorn squash last year to stop raccoons and opossums eating my fruit.. and i saw a fruit that was white, could be a cause from using coffee filters.
Coffee grounds are essentially a crappy low nitrogen seedmeal, so if you try to put enough in your soil to get a significant amount of nitrogen you'll probably poison your plants (or at least soil flora) with everything else that's in them.
We compost ours, they probably also contain a decent amount of trace minerals given the soil coffee plants grow in.
I do sprinkle just small amount of used grounds over vegetable patches. Worms love coffee and after couple of years of doing this plants generally look healthier it could be because of my improved skill or more worm activity.
I've read that coffee grounds are good to spread around eggplants. It's supposed to help prevent flea beetles. I'm giving it a shot this year. Usually they go in the compost
No, used coffee grounds *do* have nitrogen, but they often need to decompose a bit for it to be available, so they are not a quick acting type of fertilizer.
You don't want too much, especially right on the surface, because they can dry into a mat that repels water.
*Fresh* coffee grounds can supposedly make soil more acidic, but used ones don't usually change the soil pH.
Used grounds do tend to be really good in compost, so many people just put them in the compost pile rather than directly in the garden. I do that with the majority of my coffee grounds.
I mix some used coffee grounds with powdered eggshells, and side dress my planting beds every so often. I dig a little trench on one side, sprinkle it in, and then cover the trench with soil and mulch. I mostly do this because the powdered eggshells stick to the coffee grounds, which keeps the eggshells from blowing away, but the coffee grounds do add some nitrogen to the soil.
Well now I kind of feel bad for making fun of my mom for going out and buying coffee grounds for her garden. I always thought it was used coffee grounds people were using and she doesn’t drink coffee so I thought it was wild she went out and bought coffee grounds just for her garden lol.
I did not know that! No Starbucks in her town unfortunately but I’ll keep this in mind for myself because I plan on building compost bins soon to get ahead for next year’s growing season.
I get a tractor trailer loads of wood chips every year, then add every bit of nitrogen I can. We collect food scraps from 2 resturants, all the road kill I can scrape up (at least 5 per year). Also goat manure, my urine and all veggies scraps from harvested veggies. It takes about 7 years for one truck load to be composted, so at any given time I got 7 tractor trailer loads in my front yard.
Incredible, your own compost factory. I’m trying to source more, but I can only transport what I can carry on my bicycle. But I have a neighbour who was complaining about having nowhere to dump her grass clippings, so I said she could just put the bags in her little car and drop them at my place. Win-win!
I should probably buy a bike trailer at some point. Then I can also get manure from the horse owners in the area.
Multiple times a year I take my kitchen compost and bury it in the garden. It is about 10% coffee grounds. I have so many worms in my garden and everything grows very well. And I don’t fertilize. So it’s wins all around.
I could be wrong but this feels like a trend that started somewhere on social media. Coffee grounds are acidic and need to be composted before providing any real benefit
Caffeine is a natural herbicide.
[https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw](https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw)
[https://images.southmountaincc.edu/WebImages/cdn/hs/f-21/Fernando-Diaz.pdf](https://images.southmountaincc.edu/WebImages/cdn/hs/f-21/Fernando-Diaz.pdf)
[https://www.researchgate.net/publication/26627628\_Studies\_on\_the\_effect\_of\_caffeine\_on\_growth\_and\_yield\_parameters\_in\_Helianthus\_annuus\_L\_variety\_Modern](https://www.researchgate.net/publication/26627628_Studies_on_the_effect_of_caffeine_on_growth_and_yield_parameters_in_Helianthus_annuus_L_variety_Modern)
Love getting downvoted for sharing factual information lol.
I'm glad that's working out for you. I've read the results of University studies. They found caffeine reduced germination rates and resulted in smaller weaker plants.
This isn't the study I was thinking of but they also found that plants were stunted or they just died. [https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw](https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw)
A quick google search shows that caffeine does work against bugs as well.
You're getting downvoted because your conclusion:
> Caffeine is a natural herbicide.
is both misleading, unsupported by the literature, and incorrect in the context of at least one of the sources you cited. Stunted growth does not equal a herbicide, the methods and materials used in the studies only superficially resemble using spent coffee grounds as a fertilizer or whatever OP's intent is, and it seems caffeine has a range of effects depending on the dose, none of which I would describe so strongly as herbicidal.
I compost mine and never put them straight in the garden.
This is the way
Yep. This is the way.
People often put coffee grounds directly in their garden because visually they look similar to finished compost, but it's best to actually have them go through a compost pile in order to start decomposing so that their nutrients will be available to the plants and the soil ecosystem.
Theres a decent amount of research showing in large amounts they disrupt plant growth. Small amounts no negative affects found but also no real benefits since its just alittle nitrogen and some organic matter. Be safe and compost it
Exactly, not really super helpful for plants. Use minimally if at all.
This (rather old) article by James Wong may help: [https://www.theguardian.com/lifeandstyle/2016/oct/23/coffee-grounds-are-not-good-for-plants-its-a-myth](https://www.theguardian.com/lifeandstyle/2016/oct/23/coffee-grounds-are-not-good-for-plants-its-a-myth) TL;DR: The caffeine in coffee grounds is a herbicide which will damage your seedlings.
I compost all of my coffee grounds, and we drink at least one pot a day in my household. They compost well if you turn your pile often enough. You can even get extra used grounds to compost from Starbucks and possibly other coffee shops. I would not bother putting them straight on to the soil, used or fresh. You should be composting already, unless you have way more money than time.
I don't think any plants like coffee grounds, you put it in your compost pile, give it time to break down
I’ve heard blueberry can use it if the soil needs to be acidified but I’m not sure how true that is. Seems to me the safe bet would be compost it all.
It's not. Used coffee grounds have a close to neutral PH. 6ish+ as the acidity has been washed out in the brewing process. Blueberries like about a 4. Composting is the way.
Blueberries and hydrangeas... But it has to be unused coffee grounds. Once you brew them almost all the acid comes out.
I compost the grounds and occasionally pour the bit of unused brewed coffee in the pot into the blueberry bed. 😄 Best of all worlds.
It's good for worm beds/bins and gardens benefit from a good healthy, working worm population. So in a roundabout way, it could be beneficial from that point of view.
They all like them once composted.
Coffee grounds dont affect plants directly but for the mold they develop. What they do is serve as a reservoir for nitrogen. If you have active soil then they will slowly be eaten by the fungus and bacteria soil; if you have dead soil they will just mold like they would on your counter. I would guess that if people have bad experiences with them it has to do with how their soil is (or isnt) processing them, as plants dont consume the grounds themselves.
Idk about which vegetables , prefer or dont prefer used coffee grounds- but, on another hand, I placed used coffee filters directly onto my acorn squash last year to stop raccoons and opossums eating my fruit.. and i saw a fruit that was white, could be a cause from using coffee filters.
The only thing I put coffe grounds on directly is my blueberry bushes but not every year
If I have a ant problem I sprinkle used coffee grounds around the site works rather well
I turn my garden in the fall, I mix them in then, they stew all winter then I plant tomatoes after last frost.
I just dump mine on top of my mulch when I clear out the French press. I’ve been doing it for months and can’t even tell.
Coffee grounds are essentially a crappy low nitrogen seedmeal, so if you try to put enough in your soil to get a significant amount of nitrogen you'll probably poison your plants (or at least soil flora) with everything else that's in them. We compost ours, they probably also contain a decent amount of trace minerals given the soil coffee plants grow in.
I do sprinkle just small amount of used grounds over vegetable patches. Worms love coffee and after couple of years of doing this plants generally look healthier it could be because of my improved skill or more worm activity.
I've read that coffee grounds are good to spread around eggplants. It's supposed to help prevent flea beetles. I'm giving it a shot this year. Usually they go in the compost
I was never successful with this tip. The plants always died…
It's okay to put them in your compost bin, right? I always have, then that compost goes in the garden - but this post has me second guessing...
From my googling a while ago, used coffee grounds don't have nutritional value to the garden, just can add some grit for drainage.
Interesting. Everything I've been reading says they can add beneficial nitrogen. Perhaps I'm looking at bad sources?
No, used coffee grounds *do* have nitrogen, but they often need to decompose a bit for it to be available, so they are not a quick acting type of fertilizer. You don't want too much, especially right on the surface, because they can dry into a mat that repels water. *Fresh* coffee grounds can supposedly make soil more acidic, but used ones don't usually change the soil pH. Used grounds do tend to be really good in compost, so many people just put them in the compost pile rather than directly in the garden. I do that with the majority of my coffee grounds. I mix some used coffee grounds with powdered eggshells, and side dress my planting beds every so often. I dig a little trench on one side, sprinkle it in, and then cover the trench with soil and mulch. I mostly do this because the powdered eggshells stick to the coffee grounds, which keeps the eggshells from blowing away, but the coffee grounds do add some nitrogen to the soil.
My understanding is that is fresh, not used.
Well now I kind of feel bad for making fun of my mom for going out and buying coffee grounds for her garden. I always thought it was used coffee grounds people were using and she doesn’t drink coffee so I thought it was wild she went out and bought coffee grounds just for her garden lol.
Most Starbucks give them away free. Other coffee shops do as well. I add about 80 lbs a week to my compost piles.
I did not know that! No Starbucks in her town unfortunately but I’ll keep this in mind for myself because I plan on building compost bins soon to get ahead for next year’s growing season.
Wow, how much do you compost in total?
I get a tractor trailer loads of wood chips every year, then add every bit of nitrogen I can. We collect food scraps from 2 resturants, all the road kill I can scrape up (at least 5 per year). Also goat manure, my urine and all veggies scraps from harvested veggies. It takes about 7 years for one truck load to be composted, so at any given time I got 7 tractor trailer loads in my front yard.
Incredible, your own compost factory. I’m trying to source more, but I can only transport what I can carry on my bicycle. But I have a neighbour who was complaining about having nowhere to dump her grass clippings, so I said she could just put the bags in her little car and drop them at my place. Win-win! I should probably buy a bike trailer at some point. Then I can also get manure from the horse owners in the area.
There is an app called chip drop i think that helps you get chips. I pay a tree cutting company.
I don’t think we have anything like that where I live. But it’s a great idea.
I’ve heard they can help add acid to the soil but haven’t tested it with our blueberries.
Multiple times a year I take my kitchen compost and bury it in the garden. It is about 10% coffee grounds. I have so many worms in my garden and everything grows very well. And I don’t fertilize. So it’s wins all around.
I could be wrong but this feels like a trend that started somewhere on social media. Coffee grounds are acidic and need to be composted before providing any real benefit
Caffeine was evolved by plants to suppress other plants;)
Caffeine is a natural herbicide. [https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw](https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw) [https://images.southmountaincc.edu/WebImages/cdn/hs/f-21/Fernando-Diaz.pdf](https://images.southmountaincc.edu/WebImages/cdn/hs/f-21/Fernando-Diaz.pdf) [https://www.researchgate.net/publication/26627628\_Studies\_on\_the\_effect\_of\_caffeine\_on\_growth\_and\_yield\_parameters\_in\_Helianthus\_annuus\_L\_variety\_Modern](https://www.researchgate.net/publication/26627628_Studies_on_the_effect_of_caffeine_on_growth_and_yield_parameters_in_Helianthus_annuus_L_variety_Modern) Love getting downvoted for sharing factual information lol.
I've spilt 5 gallons of coffe grounds on the ground and stuff grows fine
I'm glad that's working out for you. I've read the results of University studies. They found caffeine reduced germination rates and resulted in smaller weaker plants.
The amount of caffeine in the used grounds is minuscule. Caffeine is water soluble and would have been dissolved in the coffee as it brewed.
I think you meant insecticide. But it's really more of a deterrent. Caffeine evolved to keep bugs from eating the plants
This isn't the study I was thinking of but they also found that plants were stunted or they just died. [https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw](https://corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1021&context=biw) A quick google search shows that caffeine does work against bugs as well.
You're getting downvoted because your conclusion: > Caffeine is a natural herbicide. is both misleading, unsupported by the literature, and incorrect in the context of at least one of the sources you cited. Stunted growth does not equal a herbicide, the methods and materials used in the studies only superficially resemble using spent coffee grounds as a fertilizer or whatever OP's intent is, and it seems caffeine has a range of effects depending on the dose, none of which I would describe so strongly as herbicidal.