I agree with Dylans stance on this, However there are electric sterilisers available which can provide a little heat if used in the green house in winter. The soil to sterilise is old potting soil or soil infested with unwanted desieses, plants or seeds. http://greenhousepeople.co.uk/accessories/… Peter uk On Wed, Apr 3, 2013 at 11:49 PM, Hannon <othonna@gmail.com> wrote: > Agreed with Russ that one should be cautious in "sterilizing" potting > media. The clean slate so created invites all comers, from beneficial to > pathogenic. Better to pasteureize at lower temps to redue the chance of > catastrophic outbreaks. For seeds I use a mix of perlite, coarse builder's > sand and an off-the-shelf organic component like peat or Edna's at roughly > 2:1:2 respectively. Some fine charcoal is also beneficial. None of these is > exactly sterile but they are clean enough. It is impossible to know if > outbreaks of pathogens are in the soil to begin with or have blown in from > afar. > > Dylan > >