I am relatively new to seed starting .

I sowed some geranium seeds in a regular potting mix.
after just a few days i saw some mold that was starting to build on the soil surface.
so i sprayed it with captan and it killed the mold alright .
after two weeks with no germination (of 50 seeds) i started to dig in the soil to see what's going on.
many of the seeds just vanished.
But i did found some.
from the ones i found some where just empty shells , some looked OK, and some where soft.
when i pressed on them lightly all of the seed contents just spilled out as a milky white liquid.
(the only 5 seeds that looked ok , i put on a damp paper towel, and they germinated the very next day.)

my thoughts where that it was maybe a lack of air that caused them to get liquefied .

thinking i learned from past experience i now decided to start some hollyhock seeds (about a 100 of them).
so this time decided to start them on a damp paper towel.
after a few days they started to germinate, BUT also they started to develop mold.
so i used fungicide again, but this time i used myclobutanil based fungicide .
a couple of days later and all of the little roots that started to pop out vanished , and the inside of the seeds turned into the same milky liquid as it happened with the geranium seeds.

I am in Israel , it is considered to be zone 11.
temperature at this time of the year , are around 32C 90F on average and can sometimes get over 100F on hot days.
Lately i also get many cuttings rotting on me.

So
where is the blame?
Is it the high temp?
Is it mold and fungi?
can fungicide kill seeds or cause seeds to get liquefied?
Is there some other bacteria or virus that cause such thing to happen?

what can it be?
I don't want any more seeds to die like this.
can you help?

PS all seeds where sowed indoors.
i did sowed some Mirabilis jalapa (the four o'clock flower) outdoors and they too turned into a white liquid on the inside. (for them as well, i mixed some captan powder with the soil.)