Most everything you need to know about Used Coffee Grounds

Ooooh, sounds interesting, more fun with fermentation!! I look forward to trying it.
Thanks for sharing your knowledge, Dr RedHawk!

Hi. I save my coffee grounds every morning in a open container. I notice went i emptied the container a greenish powder flies. Is this good or bad, assuming it's mold?! Not sure if this should be going into my composter/garden or not. Also, i breathed some in 🤦‍♀️

Michael Dobbins wrote: Another trick to watch honey bees is to put out 1-1 sugar syrup: a cup of white cane sugar and a cup of hot water, stir until dissolved, let cool, and put out on a plate to keep the liquid shallow enough to not drown bees.

This is a bit OT with regards to the topic but as this thread received a new post I read through the older posts, including this one.
Two thoughts:
* Feeding bees in the open can transmit diseases and parasites and induce robbery (one spot of accessible food makes bees look for more, and they can enter a hive and seriously damage bee population in there)
* If you dissolve the sugar with hot water Hydroxymethylfurfural can be found in the solution which is toxic for bees

So please don't feed bees other than with a wide selection of trees and flowers, or with adequate syrup if you are a beekeeper.

Bryant RedHawk wrote:

Organic guidelines allow these sprays to be used, more proof that the term Organic is not what most people think it means.

I had started eating a largely organic diet many years ago. I noticed eventually that I just wasn't getting the pep in my step and the overall satisfaction from eating and cooking purely organic. This is when I realized that organic had truly become OrScamic. Another good thing ruined by profiteers.

To split hairs coffee beans are not beans, " It is the pip inside the red or purple fruit often referred to as a cherry. Just like ordinary cherries, the coffee fruit is also a so-called stone fruit."
I worked in one of two coffee process plants in South Carolina for 37.5 years. I have composted dry green coffee beans, roasted coffee beans, ground roasted coffee that has not been used &   is  five days old(most store bought coffee is 30-270 days old). But the best is the coffee chaff, we ran water over the chaff, to lower it's flesh point to zero. The chaff is dry & hot then wet & it goes though a heat as it is put in supersacks, supersack is a brand name for a 4 feet cube sack for shipping product, in this case green coffee beans, then recycled for waste coffee chaff.
So when you haul the 1500 pounds of chaff away, it has already started to break down, it is the consistency of onion skins, paper thin, hot & wet. The compost stay in the soil longer than any other plant matter I have used IMHO. Leaves & grass is good, but not like chaff.
All coffee products are good for composting or turning into garden, I have done both in the past. I put chaff on surface of the garden as a mulch & it cracked in hot weather & mud in wet weather, so it acted like clay until it broke down. If you covered it with wood chips, it may not be the problem I had, but composting it will do the trick.

I throw coffee in the same filters into my blueberry bed, occasionally at the base of other fruit trees, and put lots in my compost. I see no sign of filters after a few weeks or months. They do biodegrade nicely.

Need to be careful with this...
I've heard from several people who had their plants die from using coffee grounds...

I put some wheat straw from a field on my garden once... Killed almost everything...
https://lairdsuperfood.com/blogs/news/121150145-conventional-coffee-most-loaded-with-pesticides-a-case-for-organic-coffee

John Russey, thanks for the reminder.  Here is more information from the original post:

Bryant RedHawk wrote:Having used spent coffee grounds since 1970 for a myrad of purposes in gardens, farms and for other growing purposes,  I thought it would be a good idea to build a reference thread for this wonderful amendment.
There are definitely pros and cons to using spent coffee grounds as well as several ways to utilize them in gardening/farming...

Not all plants get a jolt from coffee grounds:

Seed germination of alfalfa (Medicago sativa) and white and red clovers (Trifolium repens and T. pratense)
was inhibited by water leached through coffee grounds. Growth of crops such as Chinese mustard (Brassica juncea),
komatsuna (Brassica campestris) and Italian ryegrass (Lolium multiflorum) were all inhibited by coffee grounds, as
was that of ornamentals including inch plant (Tradescantia albiflora), geranium, and asparagus fern. One investigator
speculated that toxic substances released from decomposing coffee grounds were responsible for their inhibitory effect.
This effect also reduces weeds, and perhaps in a landscape dominated by large shrubs and trees, only germinating seeds
and seedlings would be injured. But there has been no experimental research on coffee grounds and woody plants published to date.

Percentages of 10 to 20 percent of total compost volume have been reported as optimal for compost quality and
effectiveness, while over 30 percent can be detrimental.

Only small amounts of coffee grounds are required for effective disease suppression. Therefore, it is recommended
using no more than 20% by volume of coffee grounds in a compost pile. A diverse feedstock will ensure a diversity
of microorganisms....

Given the quantity of research that has been done on refuse of coffee production and the lack of research done on spent coffee grounds specifically, there is much work to be done to discover all the best uses of spent coffee grounds.

I hope this information is useful to you.

If spent coffee grounds have such a high nitrogen content, would it be a good thing to use on my lawn? We have places were Clover has taken over and I read somewhere here that clover is a sign of nitrogen deficiency??

Somewhat misleading.
Nitogen ? Coffee grounds rank only a 1 on the N in an NPK ranking.
Without composting . them first,   coffee grounds contain caffeine. Caffeine can be  problematic. Best to use that only on paths to inhibit weeds.

Thankyou great information

Hi, When using coffee grounds it is very advisable to check and see if there is any DDT in them.  The US chemical factory sells DDT to companies not in the US who use it on a whole host of products. Coffee is one. I used to drink a specific brand of coffee. It left a stinging burning sensation in my throat. A friend of mine said it was probably residual DDT. I had the coffee tested and there was an "acceptable" amount of DDT in the beans. I quit drinking that brand.

I am now more careful what I put into myself and in my soil.

I am currently researching utilizing used coffee grounds in compost and this was very helpful information.

Thank you, from Kansas, USA.

John Russey wrote:Need to be careful with this...
I've heard from several people who had their plants die from using coffee grounds...

I put some wheat straw from a field on my garden once... Killed almost everything...
https://lairdsuperfood.com/blogs/news/121150145-conventional-coffee-most-loaded-with-pesticides-a-case-for-organic-coffee

With all due respect.
It has to be something other than just coffee, I have put pure coffee on the ground & the grass grew though it pretty & green.
I put chaff & ground coffee down as mulch & it never hurt my tomatoes or Blueberries. as stated above it would crack open when dry & be messy when wet like clay, but my tomatoes grew
from N-P-K & trace elements. I put it down by the pounds/ truck load, all I got was more vegetables & greener weeds. I still have compost from two years ago & no dying plants of any kind.

Hmm. Maybe it has to do with the pesticides that may be used? Wheat straw ought to be benign--but they're now spraying it with glyphosate at harvest to get it dry faster. I use coffee grounds on my blueberries, no problem, nbut I buy organic coffee. I wouls kindof think that if it was toxic to plants, it would be dangerous to drink...

Suzanne Cornell wrote:I have a coffee ground question. I spilled coffee grounds on the way to the compost pile, and the next day the pile of coffee was covered with honey bees. Is it the nitrogen they are after? Why would they love coffee grounds?

I noticed this just this past weekend.  Weather is warming, there was a pile of coffee grounds on the edge of the compost pile, and there were LOTS of honey bees on it.  No flowers out, as it is too early in the season.  I was surprised they were out so early, and that there were so many.

John Russey wrote:Need to be careful with this...
I've heard from several people who had their plants die from using coffee grounds...

2 years ago, I collected A LOT of coffee grounds from starbucks and others.  Just dumped them into the garden in a row all winter, tilled them in in the spring, no composting.  The spot where the grounds were was sterilized by something... nothing would germinate.  The beans, peas, and cruciferous veggies that were planted in rows through this section... just did not germinate (the rest of the row did fine, it was definitely dose dependent - closer to the patch of coffee grounds = poorer and slower germination.  Even the lambsquarter did not grow in that area until late in the season.  The next season (after tilling the soil again) the effects were far less, but plants in that area were slightly delayed in the spring, but by mid summer there was no noticeable impact.  

Covid ended the free coffee grounds, and I had decided that I needed to add them to the compost pile, NOT directly to the garden anyway.  Now I just get the ones from my own pot and the pot at work, not the mass quantity I was collecting.  

Just an anecdote about a adding a large quantity of un-composted grounds and having issues.  

Thomas Dean wrote:

Suzanne Cornell wrote:I have a coffee ground question. I spilled coffee grounds on the way to the compost pile, and the next day the pile of coffee was covered with honey bees. Is it the nitrogen they are after? Why would they love coffee grounds?

I noticed this just this past weekend.  Weather is warming, there was a pile of coffee grounds on the edge of the compost pile, and there were LOTS of honey bees on it.  No flowers out, as it is too early in the season.  I was surprised they were out so early, and that there were so many.

The bees are after the moisture in the coffee grounds.  They need a water source so that is where they are getting it.

It is nice that you have o many bees.

Anne Miller wrote:

Thomas Dean wrote:

Suzanne Cornell wrote:I have a coffee ground question. I spilled coffee grounds on the way to the compost pile, and the next day the pile of coffee was covered with honey bees. Is it the nitrogen they are after? Why would they love coffee grounds?

I noticed this just this past weekend.  Weather is warming, there was a pile of coffee grounds on the edge of the compost pile, and there were LOTS of honey bees on it.  No flowers out, as it is too early in the season.  I was surprised they were out so early, and that there were so many.

The bees are after the moisture in the coffee grounds.  They need a water source so that is where they are getting it.

It is nice that you have o many bees.

That's odd... there were lots of other water sources around... and yet they choose coffee... but I guess that's what I do, so why question them.  
But still, I think that there must be something else they are looking for

I have a drip coffee system, a Melita cone. It does use paper filters but they go into the compost. I have never owned an electric coffee maker and my coffee cone is probably 40 years old. Hasn't broken yet!

I save my coffee grounds in an open container, allowing them to dry out. I save my egg shells, too.

Once they are dry, I grind up the egg shells (in a dedicated grinder), mix them with the dry coffee grounds and scatter them in my garden.

From what I have learned, worms love egg shells and coffee grounds. So, what better purpose than putting them into my gardens?

When I was farming (in my past life), often in spring there would be masses of ants coming out in the warm weather. I discovered that spent coffee grounds would chase them away. So, I would sprinkle coffee grounds on the ants...and they would leave. Works around the house, too.

I have had an ant challenge in my garden (a small, raised bed here on the grounds where I now live) with ants. In May, there are thousands of flying ants coming out of the untreated wood sides of the raised beds. Not only my plot but many others. Since I was granted this garden plot, I have used spent coffee grounds and egg shells in the garden. I have seen fewer ants over the past two years. So, there must be something about coffee grounds and ants.

It's a shame to toss out things that may prove to be useful in the future.

hau Cynda, SCG also work on termites too. Termites also spread by winged ones. Leaving their colony to start new colonies.

Redhawk

Bryant RedHawk]hau Cynda, SCG also work on termites too. Termites also spread by winged ones. Leaving their colony to start new colonies.

Redhawk...

I did NOT know that coffee grounds will repel termites!!! Since I also have a termite issue (they are living in the garden soil and (I'm sure) the untreated sides of the raised beds) and they eat the stems of my plants and entire radishes, I guess I will increase the amount of coffee I drink!!!

Can you tell me if the flying termites are white? I know the ones who I find chewing my garden plants are white. But the flying insects I discovered several seasons ago (in May) had black bodies. I thought they were ants but maybe they were termites?

Do you have any idea how much coffee grounds I need to apply? A rough estimate would be helpful!

I do drench the soil with Neem oil and water mixed. It's a job to do it, but I think it has helped with the ants & termites. But the termites come back.

I do love the information I find on this site!

I grind up my eggshells too--to feed the hens to replenish their calcium supply, along with occasional oystershell. As fir coffee fgrounds, I recently read a suggestion to mix them into the soil where you plan to plant carrots, to repel the carrot fly. I'm going to try it, even though it means I have to save my coffee grounds instead of dropping the filter and grounds into my blueberry bed, or lobbing it at a bush.

cynda williams wrote:

I did NOT know that coffee grounds will repel termites!!! Since I also have a termite issue (they are living in the garden soil and (I'm sure) the untreated sides of the raised beds) and they eat the stems of my plants and entire radishes, I guess I will increase the amount of coffee I drink!!!

Can you tell me if the flying termites are white? I know the ones who I find chewing my garden plants are white. But the flying insects I discovered several seasons ago (in May) had black bodies. I thought they were ants but maybe they were termites?

Do you have any idea how much coffee grounds I need to apply? A rough estimate would be helpful!

I do drench the soil with Neem oil and water mixed. It's a job to do it, but I think it has helped with the ants & termites. But the termites come back.

I do love the information I find on this site!

Flying termites are black bodied, ants are brown. I too use untreated boards for beds, I use a 3" wide x 2.5" deep ring against the inside of the beds boards to keep termites from getting into the garden as much as possible.

Redhawk

Coffee grounds and used tea bags are still very high in caffeine which is toxic to dogs (don't know about other animals); please use care if putting out and about or in compost if you have dogs - ingestion of sufficient quantities (depends on size of dog) can be fatal.  Below is from the pet poison hotline:

"Caffeine is most commonly found in coffee, coffee grounds, tea, used tea bags

Threat to pets:  Pets are more sensitive to the effects of caffeine than people are. While 1-2 laps of coffee, tea or soda will not contain enough caffeine to cause poisoning in most pets, the ingestion of moderate amounts of coffee grounds, tea bags can easily cause death in small dogs or cats.

Signs of caffeine poisoning: Within 1-2 hours of exposure: mild to severe hyperactivity, restlessness, vomiting, tachycardia (elevated heart rate), hypertension (elevated blood pressure), abnormal heart rhythms, tremors, hyperthermia (elevated body temperature) seizures, and collapse.

Treatment: Induce vomiting and give multiple doses activated charcoal to decontaminate. Aggressive IV fluids to help with excretion, sedatives to calm the pet, specific heart medications to reduce the heart rate and blood pressure, anti-convulsants for seizures, antacids (such as Pepcid) for stomach discomfort and diarrhea. Caffeine may be reabsorbed across the bladder wall so a urinary catheter or frequent walks are needed to keep the bladder empty.

Prognosis: Excellent in pets with mild signs of poisoning (such as slight restlessness or a minimally elevated heart rate). Poor in those with severe signs of poisoning such as collapse and seizures."    

https://www.petpoisonhelpline.com/pet-safety-tips/is-caffeine-poisonous-to-dogs/

This is an interesting article on bees and coffee, towards the article end it mentioned how lots of flowers are caffeine rich.

https://www.nytimes.com/2015/10/19/science/the-caffeinated-lives-of-bees.html

Bryant RedHawk wrote:The model I am working through at this time calls for gathering the grounds and letting the normal fungi grow till they are spent.
From that point the grounds are stirred and dried completely before being incorporated into finished compost which is then used as a soil amendment in soil garden beds.
The subject beds are ground level, raised bed, and hugel mound topping along with a straw bale garden.
Results of this three year study will be posted here when completed.

@Bryant Redhawk, did you end up posting your results somewhere?  I'd love to know what happened...

I am continuing this experiment. The initial plot showed a 78.6 % increase in earthworm population, a 79.7 % increase in overall bacterial population and a 57.6 % increase in fungal hyphae coverage from 2 cm depth to 18 cm depth.

The repeatability of the results are in process currently.

Redhawk

Bryant RedHawk wrote:hau Tereza, it sounds to me like they are leaching out Nitrogen compounds then using the supernate (the liquid) to water with.

Fermenting SCG isn't even close to a bad idea, the bacteria that do the fermenting get healthy and feed on the component parts of the grounds as well as making new compounds.
You can add them to a bokashi where they seem to act like superchargers to the bacteria growing in the bokashi. This should work anywhere you place SCG that has a good microbiome.

I agree that fermenting used coffee grounds in a bokashi system works a treat. You may need to spray some water onto the grounds if adding a bulk amount into a bokashi bin, as the EM need moist conditions to proliferate.

Bees use caffeine to ward off Serratia marcescens, a bacterial pathogen known to cause sepsis in animals.  I wanted to read the other bee and caffeine article but don't pay for the New York Times so looked for another article.

Bees and caffeine

Tina, thanks for sharing that article.  Now the mystery is solved.

The coffee grounds are amazing.

They will add some acidity to the soil if a person has alkaline dirt like I have.

In many places they can be had for free and anything that folks can add to their soil as organic matter usually helps.

Bryant, if I wanted to do something similar, could I just mix some rotted wood chips with the coffee grounds I can get from local coffee shops, and let them sit around in a bin or bucket for a few months before applying them?

I see that I posted here a year ago, mentioning my plan to try out the tip I'd gotten that used ground in the furrow where carrots are planted will help with the flies or worms or whatever it is that causes black tunnels mostly in the stem part of the carrot root. I did try it last year. Result: the bed I added coffee grounds to got MORE tunnels than the control. Back to giving the grounds to my blueberries and other bushes.

There's a local firm who goes around all the restaurants and coffee shops collecting their grounds. This is then used to grow mushrooms, which he sells.

cynda williams wrote:I have a drip coffee system, a Melita cone. It does use paper filters but they go into the compost. I have never owned an electric coffee maker and my coffee cone is probably 40 years old. Hasn't broken yet!

I save my coffee grounds in an open container, allowing them to dry out. I save my egg shells, too.

Once they are dry, I grind up the egg shells (in a dedicated grinder), mix them with the dry coffee grounds and scatter them in my garden.

From what I have learned, worms love egg shells and coffee grounds. So, what better purpose than putting them into my gardens?

When I was farming (in my past life), often in spring there would be masses of ants coming out in the warm weather. I discovered that spent coffee grounds would chase them away. So, I would sprinkle coffee grounds on the ants...and they would leave. Works around the house, too.

I have had an ant challenge in my garden (a small, raised bed here on the grounds where I now live) with ants. In May, there are thousands of flying ants coming out of the untreated wood sides of the raised beds. Not only my plot but many others. Since I was granted this garden plot, I have used spent coffee grounds and egg shells in the garden. I have seen fewer ants over the past two years. So, there must be something about coffee grounds and ants.

It's a shame to toss out things that may prove to be useful in the future.

Wonderful tip about the ants. I don't mind the little ones. But I have nests of the big bitey ants who have no respect for me or where my wicking beds are.  So last year got bitten aplenty when watering. Now I know what to do.

To deter mosquitos from breeding there, I use coffee grounds in the cups of bromeliads  (of which I have many). It sees to work but in the rainy season repetition is necessary.
I also add it to compost in the dry season.

I have been just adding bags of spent coffee grounds from local coffee shop to the compost pile.   This fall I will add it to shredded leaves.   We have always collected some leaves in SPB (Stupid people bags per the excellent Ted talk video above) in the fall.   In the past we have not shredded but have just used it as mulch.   We have gone so far as to knock on doors and ask if they spray their lawn.   My question for you fine folks is to ask whether this last step is necessary.   Do leaves fallen on a sprayed lawn pose any threat, or can they be eagerly used as well?

I wouldn't use them from sprayed lawns.  The easier way to verify is to just look at the lawn.  If there are dandelions and clover, they don't spray.