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I had heard that coffee grounds make good compost, and I wanted to learn how to make my own starter soil, so I put these two ideas together. My spouse and I use a fair bit of tea (regular and herbal) and coffee if you add it all up. So I started saving all these grounds. Then I thought I would try an experiment. So I set up a stater box with 9 compartments with a row of my grounds (with nothing added to them) a row of Miracle Grow starter soil, and a row using compost from the town transfer station. I put two tomato seeds in each one. After a few weeks (I should have jotted down the exact date, but I didn't) this is what they looked like.

[img]https://dl.dropbox.com/u/13274362/starter_experiment_1.jpg[/img]

Coffee/tea grounds, bottom, Miracle Grow middle, and transfer station compost, top. The transfer station compost and the Miracle Grow came up at about the same time (MG may have been just a bit faster). The coffee/tea ground row was slower, but did come up and seems to be catching up. I thought that the coffee/tea grounds mixture might not be porous enough, so I stated a second experiment. I mixed equal amounts of tea/coffee grounds and town compost, and then added a liberal amount of soy meal. I planted zucchini seeds in this soil. Nothing came up. The soil in this box began to smell really bad and more like a rotting animal than that friendly smell of rotting vegetation. Then I spotted some sort of worm stick its head above the surface. I dug into the soil a bit and discovered it was full of what appear to be maggots. I thought they only grew on dead animals, but here is a (poor quality I am afraid) picture of one of them.

[img]https://dl.dropbox.com/u/13274362/maggot.jpg[/img]

So what did I learn from my experiment? Don't do that again! So if learning something is the test of a successful experiment, I guess this was not a failure. Too much Nitrogen, I would guess.

Anything anyone can teach me about all this is welcome.
jedson

To much caffeine the plant could not sleep! I really think you needed more top soil in the mix like 5 to 1 top soil!

To much caffeine the plant could not sleep!

Good point. Next time I'll have to try it with Decaf.
It does seem like a different ratio of things would be worth considering.

Jedson

Yes, the coffee grounds are NOT a balanced nutrient, just a handy to source of nitrogen to add to your compost pile. They are mentioned a lot because they are widely available in bulk and break down well because very fine textured. To grow things, they HAVE to be added to regular soil. Among other things, people have noticed when they use pure coffee grounds as a top dressing, on top of their soil, it tends to crust up and repel water.

The bad smell and larvae, suggest that you had uncomposted stuff in a situation where it was too wet and not aerated enough. The larvae at a guess are black soldier flies, which love that kind of situation. I got some in the worm bin I did last winter, which convinced me not to have a worm bin indoors!

people have noticed when they use pure coffee grounds as a top dressing, on top of their soil, it tends to crust up and repel water.

Yes, I could see that even in my little experiment. I'll look up the black soldier flies. I just want enough really good compost for starting things. I use a lot of mulch from the transfer station in my garden, and once things get stated they do pretty well there. So I guess I'll start a small compost bin and do it properly. (I have a big one that I just throw anything organic into.) Then maybe one part grounds to 5 parts town mulch. As was suggested. If I did that right would it be ready for spring planting? Should I add any of the soy meal?

Thanks for the very useful info. I into this as much for what I can learn as for the vegetables.

Jedson

Sorry to hear about that experience with coffee grounds, and as you have discovered, they are not the best for starting off seeds, and tomatoes in particular are not that fond of pre composted coffee grounds.

You will find that used grounds are very good as a compost additive, worm food, pest deterrent, and nitrogen based fertilizer to be applied (sparingly) onto plants and their soil.

I run a volunteer group that collects used coffee grounds for the above purposes, and run the Ground to Ground website - [url]https://groundtoground.org[/url], so stop by if you want to see all the things that coffee grounds can do for you.

to be applied (sparingly) onto plants and their soil

Sparingly seems to be the key word. I think I was operating on the assumption that if a little was good a lot had to be great. Cool website. Lots of interesting ideas. I know a guy who works for a small restaurant. I would guess I could get coffee grounds from them. So maybe I'll try to make a small composter and use a combination of partly composted stuff mostly leaves) from the town transfer station, coffee and tea grounds, and grass clippings as the main ingredients.

jedson

When I was reading the description of your second experiment and came to the part where you added the new ingredient, I was so ready for "s" and "o" to be followed by "I" and was thrown off when it said "y" I had to stop speed reading and re-focus.

I'm still not seeing the key ingredient here -- SOIL.
Bobberman had the right idea. I prefer 3 parts top soil (usually just below a pile of leaves), 2 parts FINISHED compost, and 1~2 parts sand. *or some similar ratio -- I don't measure and just eye-ball it.

Is there a reason you want it to be soil-less? From all I hear, a good neutral/bulk ingredient, in that case, is finely shredded coir.

As mentioned, coffee grounds (UCG -- oh, was yours used?) is considered a Nitrogen source (higher in N if unused). Well, Soy meal is even more widely used as organic N supplement. No wonder it got smelly.

Also, using these ingredients -- UCG/soy meal + mulch -- we're looking at basic compost ingredients. So you are not likely to see favorable results when the organic matter still need to be broken down and the bacteria and fungi are vying for the nutrients.

You could easily start a very small scale compost box if you add a lot of shredded paper/cardboard and some worms.

Yes, I am starting a small composting box. The stuff from the transfer station is partially composted. They have a huge pile and maybe 20 feet tall and of composting materials. Every spring they take a bulldozer and pull a fair bit out of the center of the pile for local gardeners to use. Very nice of them, really. So I'll use this with some coffee/tea grounds and grass clippings. See what sort of mulch I can get over the summer. May add a little of the soy meal just before using it in the spring, but it doesn't seem to be a good idea to put that in until I'm ready to plant something. I have nothing against putting some actual soil in, except the soil that I have in my yard (except where I have piled on a lot of mulch, and am growing things) is not very good. Mostly clay. Could probably go find some in the woods, but is there a lot to be gained in doing so? Seeds seem to start up OK even in the "almost mulch" from the dump.

jedson

I am glad that some gardeners do this sort of thing: experiment. So many of us just go by what we have heard. Some, take things as gospel and those folks can be a little dangerous . Others, really myself included, get started doing things one way and, if it works, never try to make changes. We seldom learn anything new unless someone else does something different and catches our attention.

A somewhat controlled experiment with your own mix compared to others - good for you, Jedson!

Here are some thoughts about that municipal compost that you describe as "partially composted:" Go ahead like you are planning and finish it.

I have a neighbor who seems to think he can make compost by doing next to nothing. He has a lawn mower guy bring him regular loads of lawn clippings. Those pile up thru the spring and summer months. In the fall, he hauls in bags and bags of pine needles (and cones ) from his family home where there are something like 6 or 7 large pine trees. The old folks gotta rake the lawn and those bags have to go somewhere.

After a couple of years, he may or may not run a rototiller thru this mass of organic material. Then, he's got to get it out of his way so that more of this stuff can be dumped there! It amounts to probably 1,000 square feet and there are 4 big bins! Anyway, I've had him show up with a wheelbarrow and offer to dump it beside my garden. I've accepted . . .

I've mixed this with some fresh green material and capped it with about 6" of soil. There have been quite a few shovelfuls of soil tossed in as the pile was put together. After another 12 months, this stuff is really quite good!

And, it didn't arrive in anywhere near good condition! What a wet, moldy mess! There are even plastic bags because he often just tosses the pine needle filled bags into the bins! I'm not kidding! He will fill a garbage can with bags 2 or 3 years later when he decides to run his tiller thru it at the end of his processing!

Getting this mess all stirred up and mixing in with my garden soil makes an enormous difference in the final composted product. I think you may be surprised how your own soil might improve things, Jedson.

The neighbor has his problems and this is just random behavior - there's no experimenting on his part. I'm not going to be a solution for this one of his problems but you know ? ? . . . I could be.

Steve

Yes, I have set up my little composter.

I like doing things on the basis of my understanding rather than just following recipes. And I like experimenting. Being a real amateur at this I'm a little short on the understanding, and the results are often worse than if I had followed a recipe. But I won't starve if some of my experiments don't turn out well. Meanwhile I learn the “whyâ€