Hello Michael, I would be more worried about the effects of a suspended water table in the pots, I think this is the likely cause of the fungal problems, especially if there is a problem with the roots or basal plates of the bulbs. Another good way of getting bacterial/ fungal infections in summer dormant bulbs is to get them wet and hot -as they might have been when sitting on pallets unplunged at the end of their growing cycle - when summer heat started. A suspended water table is when the compost is waterd the water is pulled to the bottom of the pot by gravity. When enough water has drained because of gravity there is a saturated layer of compost left at the bottom of the pot because there is not any more surplus water in the upper part of the pot to push it through the drainage holes. This is easily over come by not over crocing the pot (or use porous clay pots), and by putting them in sand. A simple experiment to demonstrate is to lift a sponge from a bucket of water and suspend it, after it has drained there will still be a wet layer along the bottom of the sponge, unless you provide the water with an escape rout. As to composts I avoid wood, peat and organic ingredients for dessert and scree plants such as oncocyclus and juno Iris, Fritillaria kurdica, conica and so on. I add leaf mould for cooler growing plants such as many reticulata Iris, crocus and frits such as raddeana, and eduardii, and summer growing bulbs such as Galtonia. I find the increase in moisture and food retention very beneficial for these Peter (UK). On Sun, Aug 21, 2011 at 12:22 AM, Jane McGary <janemcgary@earthlink.net>wrote: > Michael Mace wrote about possible effects of rotting wood underneath > his bulb pots. > > I have always avoided using bark or other wood products in my > bulb-growing mixes because I felt that the fungi that decompose the > wood might also attack the tunics of the bulbs and other non-living > tissue that is still important to the plants. I know some people > think this is silly, but it has worked for me for many years. > > It's difficult to buy soil mixes that don't contain bark and sawdust. > When living in the country, I had a source of excellent natural humus > (admittedly, full of microorganisms) that made up a quarter of my > bulb mix. Now I'm growing them in pure coarse sand with a layer of > ordinary soil down below, and pea gravel on top. I do have to > fertilize them several times during the growing season but they > appear very healthy. > > Jane McGary > Portland, Oregon, USA > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >