I adapted some germination chamber plans I've seen and devised my own with materials I already had. After five days, I'm having mixed results. I know my design is less than ideal: it's horizontal, not vertical; it's done with a crockpot; and, there are no temperature or humidity controls.
What I'm hoping to achieve is consistent germination (obviously). After some tweaks this week, I can maintain 73-75 degrees, 30-32 humidity, and a soil temperature of 78-80 degrees. What I'm noticing is that I'm not getting consistent germination--even less than when I used domes and heat mats.
I know that different seeds require different conditions for germination. However, what would be a median condition that would accomdate most "garden-variety" seeds? If I increase the humidity and the soil temperature rises really high (like 90 plus degrees) is this too far of an outlier for seeds to germinate?
The germination cabinets I've used in the past circulated air so the humidity level through out the cabinet was constant or close to it, that might be part of your problem, stagnant air.
Your temp should be fairly spot on for a small setup and yes 90 degrees would be far to hot for good germination results.