Alyssum Saxatile Compactum
First of all apologies if this is a topic that has been covered before, I'm a newbie to the forum and I'm still working my way through the threads.
As the proud owner of my very first greenhouse I have been indulging in a seed sowing spree as I now have somewhere to harden off/protect my seedlings etc. In general I am more than pleased with the results having probably around an 85% germination and growing to potting on rate (the next stage is still a work in progress) but I have had a catastrophic failure with Alyssum Saxatile. Very few of the seeds germinate and those that do seem to wither leaf by leaf before they can develope.
In general all seeds up to April (including the Alyssum) have been sown the following way:
3 inch plastic pot filled with general purpose potting compost. Seeds sown to the recommended manner and enclosed in a plastic food bag supported by canes and placed on a heated windowsill propagator tray. I tend to keep the germinating seeds under cover until they have grown a reasonable distance above the soil although I am careful with the watering to prevent 'damping off' Everything seems fine for about a week after I remove the cover (and take them off the heated tray) then the edges of the lower leaves start to dry out and wither. the compost is not dry and none of the surrounding plant are effected so I'm at a bit of a loss!
Sorry for the long post but I wanted to give as much information as possible in the hopes that somebody can point me in the right direction.