First, I'm not a soil guy - just a chemist. If you used a Bayer systemic insecticide in a retail product I would guess it was Imidacloprid. If the product you used contained Imidacloprid as the insecticide, I would be very skeptical of the 30-day period in soil. What I know about the stuff is that it's degradation in soil is highly variable. It has been widely studied, and the reported half-lives in soil vary from ~90 days to several years, depending upon conditions. It's primary mode of environmental degradation is via aqueous photolysis - in aqueous solution and sunlight the half-life is hours. Rather than complicate the question, it can persist in soil for a year or more, depending upon a number of variables. The amount that is left as residual at any time will depend upon how much was applied, and how it was applied (directly in soil vs liquid spray, vs other?). All that said, Imidacloprid is used and included in a number of garden insecticides. When applied as a liquid to row crops the intervals between application and harvest are variable, but at garden application rates, which I would guess are lower than what is used for roses, the pre-harvest interval is usually about 21 days. If you applied less but no more than what would be typical in a registered veg garden application, then 21 days should be adequate. If you applied more or it was incorporated into the soil, then to it would take longer to reach soil comparable residual levels. So the answer is, it depends. How long ago and in what form did you use the stuff, and do you know if it contained Imidacloprid?

If you pile up any organic material, and many inorganic materials too, and leave them long enough they will revert back to what they originally were, soil, or at least part of what makes up soil. To have good compost you need a variety of material, the greater the variety the better your compost will be because each type will bring in this or that nutrient in greater quantities than some others. While Nitrogen, Phosphorus, and Potash are the primary nutrients others, Magnesium, and Zinc are needed by plants in fairly large quantities and many others are needed, Calcium, Iron, Sulfur, Boron, Copper, Manganese, and Molybdenum for example in smaller quantities. While coffee grounds do have a C:N ratio close to optimal they do not have all the nutrients plants need for optimal growth so compost made from just, or a majority of, coffee grounds will not be really good compost. As amazing as the bacteria that digest that material are they simply cannot put in what is not there from the start.

Dee, I too work at a library and started by "comandeering" banana and orange peels. Since I'm only in a couple of times a week, I asked if I could leave a 5-gal bucket in the breakroom. I pointed out that my bucket has a lid and our breakroom garbage does not, promised to switch it for an empty one atleast once a week, and would gladly accept plant materials from our houseplants and the floral arrangements a Friend of the Library freshens up regularly. I now have 2 co-workers who take buckets home with them and return when full plus the breakroom bucket. Slowly but surely! We have an old 10-gal aquarium that was donated eons ago for a summer kids project and I'm currently trying to figure a way to use it as a worm bin. I've never vermicomposted (yet), but I think it would be neat to have one in glass so the kids could sort of "watch the process". We get a lot of field trips during the school year and I'd like to make the most of their time at the library. If it's successful it could perhaps lead to worm bins in the classroom too :) Like Tox said: " As long as they get into a bin somewhere, consider it a success."

AlphaRed, I am afraid that in my posts I never did address the original question you posed and that we all went off on a tangent in the excitement of discussing UCGs. :O) Although I have slowed down a bit, for several years I was bringing home about 250 pounds of UCGs a week if not more. I composted the majority of it. In the winter it would be composted in windrows which were kept warm by the UCGs activating the compost every week, even at -15C to -20C. Tricky, but it can be done especially if less of the carbon add-ins are thrown into the mix during this cold season than in the summer. You undoubtedly have to add carbons (browns) such as leaves and such and I have discovered that in composting UCGs, you don't need as much as if you were composting veggies, lawn clippings, etc, BUT there are times when your UCGs will become anaerobic and start stinking if you don't supply/introduce them to air and mix those carbons in. Not something that's written in a book as to quantities so experimenting and getting to know the 'how much' and 'when to turn' things can be a learning experience. A one yard plastic compost bin? You can easily throw in a couple of 5 gallon buckets full of UCGs in there every week along with some browns/carbons and it will make some great compost. Don't forget to make sure there is sufficient moisture. I always take the hose out and mix it while the water is sprinkling on my goodies. Deanna, DH? Garden? Do outside work?? LMAO!!! :O) He's allergic to fresh air and sunshine and would rather play Resident Evil on the Wii. The lower rock wall was here when we bought the house in 2001. There was not a flower/shrub on the property and above that rock wall was just weeds going up the hill. Any secondary walls were built by me in 2003 - at no cost since I dumpster dived all summer at a brick manufacturer's place. We also grow rocks here... Not kidding. Every winter heaves more rocks out of the ground bit by bit. The coffee was picked-up daily from a gas station up the road which sold loads of the stuff. They would fill 2 to 3 cat litter buckets a day and keep them for me. I would collect every day and then deal with the UCGs on the weekends. Thanks for the compliments every one. Just remember that it's not instant, but it sure is rewarding!! And it lasts longer than granular steroids. :O)