Hello i live on a sharp rock escarpment mountain cap that is extreme in weather conditions & void of topsoil except for the 30cm or so I've slowly accumulated. I have experienced what you do scribe as dry rot almost every year for many, not that drying in our reagan of Australia has become the normal weather pattern. There is always exceptions to the rule but the problem isn't dry rot in my case it's simply dehydration because my soil becomes grossly aqua phobic during these extended dry years, & it is impossible to give enough water to my large variety of bulbs at the correct moisture levels to keep everyone happy. I have seen baseball size belladonna reduce to the size of a pickled onion in a few year dry spell. I've had 5kg Crinum scant end slowly dehydrate over a 7 year cemi dry period to a fraction of it's size & many other examples, even little freesias completely dehydrating to dead over a few years of dehydration. Even stored bulbs can quickly dehydrate if placed in too dry conditions. It's important to know your bulbs requirements, think about their natural habitats & check bulb condition regularly during storage & also occasionally check water penetration levels if you grow in ground & have aqua-phobic problems. I have now been slowly adjusting my problem with stone edging to address evaporation & penetration by making sand plugs to trowel depth & have been improving the water retention with brown & red rainforest ferro soils & verto-soils with variable clay contents, these are very rich in mineral content & productive growth on bulbs, flowering & cemi moist dormancy have improved beyond what I could have ever imagined. My offset risk is, if we get consecutive wet seasons I may have to dig the odd bulb in wetter spots but the reward has been exceptional :) Steven Hart Treats 4 Dogs Hart's Entwine Nuts & Dried Fruits Hart's Temple Oils > On 14 Jun 2016, at 7:09 am, Johannes Ulrich Urban <johannes-ulrich-urban@t-online.de> wrote: > > Dear All, > > > Potting my winter dormant bulbs and tubers is finished, so I have time again... > > What happened several times in the past with Begonias only is a strange dry rot that makes the mature tuber go very light weight and spongy and.... dead. It happened again this year but apparently the mother tuber had produces independent small ones which were ok and so numerous that some went to the BX. > > I discussed that privately with Dylan Hannon and would like to let you all have his answer: > > > Dylan wrote: In dormancy tubers can become too dry. The organic part of the mix (like peat) can become so dry that it can rob the tubers of moisture. For a variety of reasons I like to use sand (~20%) in the mix because it is very neutral and a good insulator overall. Very healthy tubers will endure a lot of abuse including water at the wrong time, but if weak they are more susceptible to everything. Also, the firmness of the soil when planting is very important-- usually the problem is that it is too loose. > > > I can fully understand what he means but as I store my bulbs in their compost in their pot, I practically never lose bulbs because of drying out. This has happened to me in the past if I kept bulbs without compost in a paper bag for example. > > And, I have not yet found that good sand that is nice and soft. Whenever I tried to use sand it formed a very hard mass somewhere in the pot, mostly in the bottom. > > What do you think? Has this dry rot also happened to your bulbs? > > > Thank you very much and bye for today > > > Uli > > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/