I like the idea except for forking the soil and cover it with plastic. I go for the least hassle way. I would dump the coffee grounds onto the mulch and water it so the coffee grounds wash down.

Other critters decompose coffee grounds besides worms. I'm not sure how long it will last.

You'll be fine as long as you don't put down more than 1/2 inch at a time. I've used them on the lawn and there it seems to vary based on the weather. If it's relatively warm, I find little evidence of grounds after a couple of weeks. If I put them down after we've had a frost, they seem to last all winter.

I hope more knowledgeable posters will give their opinions but I think the worms will need more than just UCG for food so I'd also bury some veggie kitchen scraps here and there under that mulch. The worms will turn that into lovely dark soil.

I won't live in a plastic world so wouldn't use that and also believe in working smart, not hard, so wouldn't use a garden fork that way.

Feed the worms and they will multiply. It may take a couple of years for them to make good soil but they can't help themselves. Don't use anything that's unhealthy for the worms such as synthetic fertilizers.

I've had a garden where the worms have, in 3 years, turned heavy clay subsoil into lovely dark nutritious soil. All I did was feed them by digging in veggie kitchen scraps daily for about 8 months of the year. Of course we actually eat fresh veggies daily so would have at least 2 quarts of scraps daily - might help people's health if they did this as well as the health of the worm population! :)

I did think about adding veggie scraps but didn't for a couple reasons. First, this is a common area shared by three renting neighbors. One family has little kids and I'd imagine their curiosity would be piqued by a piece of broccoli sticking up from the grounds. They keep out of this area already and I don't want to lure them in with oddities. Second, I'm trying to get a compost pile going and everything else is going into it for the time being.

As for the forking, I've decided to go against common opinion and loosen the soil manually in addition to vermi-action. It's my opinion that it is smart and is not hard work. I'm not talking about double digging here, just penetrating to about 6 inches and pulling back on the handle a bit. It opens the soil just enough to let some grounds down without seriously destroying structure; if there was any to start with.

I'm not sure what living in a plastic world is like but I ain't there. Talk to bubble boy. I do agree that plastic isn't very aesthetic in the garden, but I inherited the sheeting (apartment crawlspace) and it has its uses: solarization, frost blanket, mulch, etc. In lieu of throwing it away, I figured I could try to put it to some use. Because I don't have the benefit of time, I am looking at every option to accelerate natural processes, hence the forking and plastic.

I would really like some anecdotal results of how effectively clear plastic warms the soil. Has anyone tried this and monitored the soil temperature between covered and uncovered?

I would really like some anecdotal results of how effectively clear plastic warms the soil. Has anyone tried this and monitored the soil temperature between covered and uncovered?

I would like to see that too. I've been watching that topic for years. I read about people who are "going to try it," but I never read about the results. I think the clear and black plastic are misunderstood, also. It is my belief (without proof) that the best use for black plastic is to shade out whatever is underneath. Any heat absorbed by the blackness of the plastic I think is lost before it hits the soil. Whereas clear plastic can condense moisture underneath forming thousands of lenses which can focus the light into pin points that can heat the soil or whatever is underneath...in theory. What really happens under black and clear plastic is a mystery.

Since plastic can limit air exchange in the soil, and plant roots do need air in addition to moisture, covering soil with plastic is not a good idea. Coffee grounds can be part of the total amount of organic matter added to soil but should not be the only source of organic matter.

I'm applying the coffee grounds as an OM supplement to the mulch mix currently in place. Are there any disadvantages to adding the coffee grounds or do you suggest adding other OM simply to increase nutrient diversity?

I did some web searches about the effects of caffeine in soil. Caffeine inhibits root growth. Unfortunately, I did the searches after I had already dumped large amounts of Starbuck's UCG in my garden beds.

My legumes didn't sprout well, especially the edible pod peas. The corn thrived, the potatoes didn't seem to mind too much. It was a bad year for tomatoes, so they don't count. The carrots and radish grew ok.

My advice is to go easy with the UCG. I'll use them in the corn patch again, but after the corn has sprouted. Otherwise, they get composted or spread on the lawn.

I have had good luck with coffee grounds. The only time I had a problem was when I dumped a bagfull into the garden and then got sidetracked (seems to happen alot). It had rained alot and was probly a week before I got them spread. The spot where I dumped them did not do well that summer but the places that I just spread them did fine.

Good Luck

Carey

I would imagine that the majority of caffeine has been removed from the coffee ground during the brewing process. Caffeine becomes very soluble at high water temperatures. Additionally, I'd think that any remaining caffeine would either a) leach away or b) biodegrade. I have no scientific evidence to support fate b.

Can you post a link of what you found. I'm having difficulty finding anything about plant sensitivity. Although, apparently slugs don't like the stuff.

Attached is a link from a paper written in 2007.

Here is a link that might be useful: Scientific paper on effects of caffeine in plants

From experience...

Mix the UCGs with some of the mulch then leave it be. The worms will make their way up to eat it hence aerating the soil for you. You can remove a bit of the mulch and lay it back on top to provide a bit of shelter for them but it's not necessary.

If spread to thick, UCGs may dry out and actually repel water, but if mixed this will not happen. Also, if you do this just before a rainfall or watering, again, less chance of the repelling factor kicking in.

You are in a zone 8 so using plastic to warm things up for the worms is futile. They are already active in your soil and with time will come up to do their job - or your job for you.

I have been gardening using UCGs as my main 'green' source in the compost for a few years. I bring home about 250 lbs. of wet UCGs weekly. Some of it is used in the compost, some on the lawn, and the rest is used to make mulch for the gardens which I apply year round. The mulch is basically a mixture of UCGs, shredded leaves, and pine needles. Here's a photo of a garden just mulched with the mix.

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As you can clearly see, the addition of UCGs to the gardens has no ill effect. :O) I do this yearly to keep the weeds down but also used to have crappy soil which now is kept up to par with this simple addition.

If caffeine was detrimental to the gardens, I would have a major problem but I believe that most of the caffeine is probably removed from the UCGs in the brewing process so in essence it never is there to create a problem in the gardens.

There was not a shrub nor a flower on this property when we bought it in late 2001. The lawn was yellow by mid-June. Following is a photo taken in 2003.

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That settles it for me. I'll keeping applying directly. Do you have a UCG source other than Starbuck's?

tiffy - 250 lbs. a week!!! That's it, I'm heading to my local coffee shops tomorrow to start collecting seriously! Your garden is lovely. :-)

Which province are you in? I'm in BC but in zone 3 in the hinterland.

Taggart,

My source is the local gas station which sells more coffee than you can shake a stick at. It's convenient for me since it is on the way home. I supply them with clean buckets every day.

luckygal,
I'm on the other side of the country in Nova Scotia. The only thing I haven't been able to turn into good growing soil are these darn boulders which pop-up on the property here and there...

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But gardening around them has been a piece of cake. :O) (This is the other side about a month later. Nothing would grow here for about a year.)

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Oh, I love those boulders! We have rocks, some fairly large ones which DH has kindly moved into the garden for me. Not as large as yours of course but some had to be moved in the tractor bucket. I love rocks! Not sure why I can still say that when I have picked rocks (small ones) out of gardens for almost my entire life.

That is a very beautiful garden. Congratulations! As gently as I can, I would like to point out that you are talking about mulching established shrubs. I was thinking in terms of vegetable gardening.

I have a 'house' plant at the office that was passed down to me from previously laid-off workers. When I got it a year ago, it was in poor condition with just three leaves. I fertilized it with a combination of coffee grounds and diet coke and today the plant has more than a dozen leaves and looks beautiful.

I have found that coffee grounds will loosen clay soil, and, in moderation, I can believe that it is helpful, but overusage of UCG will stunt growth of roots.

Mild roast coffee has more caffeine than dark roast. 90% of caffeine is removed during brewing. Caffeine inhibits growth of fungi, kills certain insects, and inhibits root growth. A certain bacteria will metabolize caffeine, but even so, caffeine in the soil of coffee plantations eventually causes the coffee plantation productivity to decline.

UN-composted coffee grounds are acidic. some plants tolerate more acidic environments than others. some plants thrive in relatively acidic conditions, others thrive at a more alkaline ph. so, it depents on what's growing in the spot you're putting grounds on. i'd put them under pine trees and around berry plants for sure. i'd think they'd be fine on or under a mulch, seeing as how mulches are considered long-term investments anyway. the ph should balance out at least as quickly as the chips are consumed by organisms. but the truth is, i don't really know. perhaps it would just end up interrupting or slowing down the wood chips' mineralization process.
if i were you, i'd try a few different areas, one without any UCGs, one with a thin layer under the chips, one with a layer on the chips, maybe a couple with thicker layers. water them in. and you could even try adding wood ashes or lime to balance out the ph. but i agree with the "smarter not harder" ideology. loosen with a fork, mulch as thickly as possible, and "sweep the scraps under the carpet", as i like to say, meaning bury any nitrogenous goodies under your mulch. that will keep the nutrients from being lost to oxidization or sun exposure.....

say, see if you can't score some spent grains from your local brewery to put under that mulch of yours! that'll make you want another layer on top and another layer of chips on top of that!!

good luck.

I took some UCG to the lab today and tested their pH. I mixed them into deionized water and let sit for two hours. They tested at 6.5 with a two point calibrated pH meter.