On 05/06/20 13:23, Nick Maclaren wrote:

My problem is with seed compost, because I can't think of how to
sterilise the soil without acquiring another large device - and I have
no space left for storage.

Have you got a problem with soil-borne pathogens? I just wonder because
I not only do not sterilise any seed compost I use, but I no longer wash
the used pots I sow seeds in. I have had problems in the past with
damping-off in seed-trays covered with a plastic propagator lid, but not
recently, and I can't remember any recent problems with seeds sown in
small pots.

Although it may not be perfect for sterilising, have you tried spraying
hydrogen peroxide solution on the compost an hour or so before sowing?
It shouldn't affect the seeds (except that it /might/ improve
germination of some recalcitrant seeds), and doesn't leave any residue.

--

Jeff