He said earlier that about 500 survived? Hopefully they weren't stressed or weakened.That is still a nice number. The strongest survived, and whole they only had 2 weeks or so for superior genetics to try to play their tole, you probably did select for superior genetics a bit, though randomness and environment probably player a bigger role.
Did oryzalin play a role at all?
Ah, if temperatures get up to 30C then probably best to keep the glass covers on. I never sowed seeds in mid summer in a greenhouse, so you'll have to adapt some things, I guess. I have always sown seeds in unheated rooms during winter, so temperatures are between 15 and 20C.
The thing with 100% humidity is that it prevents plants from respiration. And if there is no respiration, there is no water uptake from the roots. Which means it cannot take up nutrients from the soil. I thought this could be a problem. But I have now several trays with lids on them at all time. And I remove condensation water from the lid once a day. So I guess that allows for enough respiration. The leaves are dry and the peat and sphagnum does slowly dry out, while condensation keeps sticking to the lid. If the medium gets to dry, I make it 'rain' by tapping the lid instead. When it gets too dry, I water. Bottom watering makes everything way too wet, so then I remove condensation water from the lid again.
No issues with mold or yellowish seedlings. So 100% humidity seems fine after all.
So I would keep the glass cover on. And just remove excess water by angling the cover once a day so they drops start to slide down under gravity. Water evaporates way faster at 30C than at 15C.
Or did they dry out despite the glass cover with condensation being on top? More shade cloth then? They don't need light to germinate initially. The summer sun has a lot of infrared light as well.
Originally I thought it best to start ventilating once the seed leaves emerge. Not even sure if that is the best thing to try at 15C.
I think I said in the guide to do a test sow first, but you both sowed everything at once