Plant growth and development depends on the temperature (as well as other factors such as watering, fertilizing and light. So the amount of time it takes daylily seeds to mature to the point of successful germination will depend on the day time and night time temperatures. Up to a certain temperature (known as the optimum temperature), seeds will develop faster the higher the temperature. After a certain temperature they will develop more slowly and at an even higher temperature (upper lethal limit) they will die and be aborted. Sorry, I do not know what those temperatures are, and do not expect that those temperatures are known for daylilies.
Arisumi, in Beltsville, Maryland, studying embryo development indicated that at 35 days (five weeks in his growing conditions) the embryos in the seeds were nearly fully developed and able to germinate on filter paper or nutrient gelatin. He did get germination and seedlings by planting 35 day old seeds in soil. The percentage success would not be relevant for normal diploid or tetraploid seeds as he was specifically working on producing triploid seedlings.
