I just purchased some mushroom compost which smell likes tar or oil. After doing some searching it seems that one reason for the dreadful coal tar smell is cresol. Cresol is created when organic substances break down and some types of fungi also smell like coal tar as well. At low levels there is no evidence it causes any problem but if you breath in high concentrations it can make your eyes and throat sore. At really high levels you can actually pass out. Not enough research has been done on this substance. Some info on naturally occurring and manufactured cresols can be found in this PDF - http://www.atsdr.cdc.gov/toxguides/toxguide-34.pdf It seems to break down readily in soil and via the action of microbes. It doesn't accumulate in the body and is excreted in urine. It can be absorbed orally, through the lungs and skin. Can't say I am very happy about the smell. I previously purchase mushroom compost and it just had a musty earthy smell so this tar smell is quite unexpected. Won't be buying it again though unless I smell it first. You have to uncover the pile to smell it because I was kicking it around with my boot prior to purchasing it and couldn't smell it until after it was scooped up and put into the trailer. Peeeuuuuw. I think for safety's sake it would be wiser not to use any compost that smells like this.

My personal opinion is that people spend far too much time worrying about soil organisms. The earth is a microbeÂs planet and we multi-celled organisms are basically insignificant in the scheme of things. One cubic inch of soil can contain over a billion organisms. Even the human body has 10 times more bacterial cells than human. Soil organisms have evolved to fill very specific niches. If a particular population has the right temperature, the right moisture, the right air, the right pH, and the right food they will grow like wild fire. As soon as any one of those environmental factors becomes limited they will slow up and eventually stop. The population does not necessarily die out; they just are not doing anything. When conditions once again become favorable they will resume their activities. A good example is that when a soil is tilled there is more oxygen available and organism go hog wild and eat up organic matter at an accelerated rate. This is how tillage reduces soil organic matter. Stop tilling and organic matter will once again begin to accumulate because the soil environment is not as good for the organic matter eaters. Adding organisms is generally a waste of time. Because whatever you add has to compete with established critters that have evolved to fill every niche in that soils environment and will out compete new arrivals. Another way to look at it is that if the organism you are interested in is suited to your soil, it will already be there. Your tillage practices, crop rotations, soil amendments, basically everything you do will influence your soil microbe populations. If you feel a need to Âhelp the little fellows out I would suggest sticking to practices that benefit the beneficialÂs and inhibit the undesirables. Rotate, minimize tillage, add organic matter, maintain pH, and minimize fallow periods.

First, conifers like pines and cedars dropping needles does not make soil acidic. That is due primarily to the underlying mineral component of the soil and the amount of rainfall the area receives. Heavy rainfall areas tend towards acidic soil. Since the vast majority of plants prefer acid soil anyway, you are probably good to go. With lots of the trees in the area, your primary concern is going to be root competition and lack of soil moisture and a sparsity of nutrients as a result. Big trees have big, aggressive root systems that hog all the goodies. Plants you select to go in this area should be drought tolerant and not have a lot of other demands regarding nutrient issues. Even then you will need to baby them for a couple of seasons with water and fertilizer until they become established. I'll second the Beth Chatto rcommendation. And I'd add The Complete Shade Garden, by George Schenk. Both should have numerous suggestion of plants recommended for dry shade.

Oh, well seems like beautiful plants with no output usually means too much nitrogen. In which case, might benefit from tilling in some fresh woodchips to suck some of that out! LOL The folks at the master gardener's tell me that most gardens that have been fertilized in prior years are usually pretty well fixed for P&K as they do not deteriorate as fast as N does and so mostly all that's needed each year is the N. But in your case, doesn't sound like you need to fertilize at all. And I have been told there is concern about runoff from garden areas where there is too much N, as it goes into ponds and streams and kills the fish. Sounds like your earthworm population will take care of itself then. You will kill some when you till but if you till when the weather is cold they will be down deep, out of the tiller's reach, and it's my understanding they lay eggs and so I'd think it'd be pretty hard to eradicate earthworms with just tilling, once they're established. I know there are a lot of people who are following a "no-till" method of garden management and I have considered doing that but my soil is not quite where I want it to be yet, and so I do still use the tiller and then I cover over where I have tilled with cardboard and then either wood chips or pulled weeds, whichever I have, to keep the wind from blowing all my hard-won garden soil away. We have been improving our garden soil for eight years now. We've tilled in leaves and wood chips for several years and I keep a compost pile for extra weeds. I dig holes in the garden along established rows and bury the contents of my kitchen compost bucket there. Do you rotate your crops? Might consider planting heavy feeders in the spots where you have beautiful plants but no output. I think brassicas are heavy feeders and if you can find plants there still might be time to get a crop out of them. Many brassicas will stand a good bit of cold and a few frosty nights. Then you could try your tomatoes in that spot next spring and see how it goes... As far as acidity goes, I think most plants like it a little on the acid side, don't they? I know I have always been cautioned not to put very much wood ash, if any from the fireplace in the garden because it makes the soil too alkaline. If your soil is too alkaline, though, I think nothing will grow, not even many weeds. I don't know how much we would need to worry about how acid the sub-soil is, you would be a better judge of that than I would. But seems like it would depend on how deep the roots of your plants go.