Dear All, With a certain delay, sorry about it, I would like to share my personal experience with naturally soil born microfauna und microflora, this is not the result of any scientific research: For many years, and more every year, I have been using my own garden compost which is made of all organic waste from my garden and kitchen with the exception of very invasive seed bearing weeds, root-weeds die off. I add small amounts of horse manure, some shredded wood, small amounts of cinder from my log burner and some handfuls of finely ground basaltic rock (powder-fine) and finely sieved clay if I have the latter. No lime added. This compost is left one year to accumulate, then shifted the old fashioned way inside out and upside down into another compartment of my compost place and left another year to settle and rot on. It is watered in dry weather. This compost is used without anything else added to repot my bulbs and summer pots in spring, the greedy ones like many Aroids or Hedychiums get some extra balanced mineral fertilizer with it into the pot. I started in a way reluctantly because I did not know how nutrient rich this compost would be, also I was worried about fungal attacks or other microbiological problem. NONE of this happened. NEVER. I am sure that this natual compost is very rich in all sorts of micro-life and I am convinced that it is this diversity that prevents disease. So gradually I increase the use of pure compost in pots even with more demanding plants, and even with those that do not tolerate high nutrient levels like some Impatiens species: no failure so far. Same with my garden soil. I use this compost when I dig the vegetable plot(I garden on sandy soil) as well as for mulching permanent plantings, no disease. The soil in the vegetable section in the garden has become something like a soft yeast-dough after many years of organic compost gardening. The voles like it as it is so nice to tunnel.... For epiphytic cacti, philodendron and fine rooted orchids I prepare another compost made of shredded wood, lawn clippings and fresh horse manure only, let it rot at least one year and mix this with Perlite or Vermiculite and Seramis (baked clay granules) equal parts. It is not stable for long term plantings (still more stable than pure garden compost) but works wonders especially in epiphytic cacti. Here I get slightly off topic but I am telling this because in this compost I often find fungal mycelium, even small mushrooms pop up from time to time but with definetely less damage to the plants I would have in commercial compost. Most plants are fertilized with a balanced liquid commercial fertilizer as summer goes on. The result is always stable and long lasting as the compost seems to store and release the nutrients very well. There are two disadvantages using this natural compost in pots: it contains may viable seeds and the pots must be weeded 2 or 3 times during summer. The other disadvantage is that it being pure organic matter it keeps settling in the pot and will not last for more than one season. (The Vermiculite/Seramis/Perlite makes it much more stable) It shrinks in the pot and by only topping it up in spring it forms a kind of sluge in the bottom of the pot which I do not like. All my bigger pots are attached to an automatic watering system that waters each pot individually on demand and this sludge might obstruct the drainage holes. I do not use this garden compost for sowing seed or very small plants because of the load of seeds in the compost, I would find it too difficult to distinguish the wanted seedlings or plantlets from the undesired ones (nice suprises sometimes, though). To do this it means that I do not buy anything, no Mycorrhiza (I tried but found no difference in what I do anyway) so this is a very cheap and environmental friendly method of saving expensive commercial bagged compost which can be VERY unpredictable, even in good brands. (I do buy bagged compost for long term potted plants because it remains stable for many years) It springs to my mind that Janis Ruksans has a passage in his book 'Buried Treasures' where he describes desaster after soil-sterilisation. After he switched back to his well worked non sterilized soil the problem stopped. Hope this gives you some ideas about my 'inoculation' Uli