Hey Aula. So, I always have them here growing for the
rabbits fodder (I don't grow for the fruit, they are cheap as dirt here). I let them sprout on the counter (just a sprout, no leaves) and throw them in the
yard, I literally don't even bury them. About half will take and half will not. I do notice that they grow on their own time. Your weather there looks similar to mine, and by now they should be running like crazy. They get burned by frost, even mild frost, but usually come back, so it might be a question of getting rain. Right now after we broke our winter drought they are running like nuts.
The ones that do best are in a somewhat shaded place (protected) where they get regular
water (two are doing well under squash leaves). Once the tendril comes out the
roots will go down, but it won't go past that tendril til the roots find a place to bury themselves. And it's typical vine: it may sleep for months, but once it starts to go, it explodes and will cover your car.
When your other ones died, did they not put down roots? Any chance they dried out?