Why havent my seeds germinated?

The answer is they may or may not! it could be a number of factors influencing the germination process. 1 the seeds may be poor germinators or just slow to germinate, I have had seeds I have planted take 12 months or more depending on what they are before they have germinated. 2> you say you have kept them moist it may be that they have been too moist and rotted in the ground. 3. it may be seasonal and it is just too hot or cold for them at the present time. Give them time and see what happens or talk to the seed supplier and see what they have to say about their germination rates and times, and what conditions they should be grown under.