Can you recommend a good peat-free seed compost? Or do you make your own?
THe only seed composts I've found have peat in them. And peat-free composts are made from bark, which is too chunky for seeds.
My home made compost is much finer. Can I sterilise it by baking in the oven? If so - what temperature and how long? And then mix it with sand?
Yes. A temperature of 210 deg. F maintained for 20 minutes will completely sterilise the compost. You should then leave the compost to stand for a couple of weeks before mixing it up and using it.
Hi Hugh, I must say that you must have an understanding wife (that's if your married) to allow you to "bake" compost in "HER" oven (if she has a sister send her my way) because if i did that, my wife would make me into compost.
I read when propagating Ferns it help to sterilies the compost by pouring boiling water over compost first, would this way not help.
later
windy
Although I have a very understanding wife, windy, I do not use her oven, but a soil sterilizer which I made especially for the purpose.
Pouring boiling water over the compost would certainly go some way towards sterilisation - it is indeed one of the well established (if not too effective) ways of soil sterilisation. However, to have any real effect it has to be repeated several times until the temperature of the compost is brought up throughout to a proper level, and the number of times this is necessary will obviously depend on the relative density of the compost and the degree of sterilisation required. The soil temperatures required for different degrees of sterilisation are:
Deg F Organisms
130 Weeds, earthworms, eelworm etc.
160 Wireworm, non-spore forming fungi, bacteria
180 Most viruses
200 Tomato mosaic and remaining viruses
As most compost contains a variety of lumps it is customary to allow a few extra degrees (the 210 deg I mentioned) to ensure complete heat penetration.
Aqui, I bought a John Innes type seed compost from Homebase earlier this year. I wouldn't say it was fantastic, but it was ok. Perhaps if you added some vermiculite or perlite to it, it would be better.