Plants keep dieing in rockwool cubes

[Surfnbird]

ok so all my plants keep dieing when i put them in rockwool cubes. i start the seeds in a wet paper towel then put them in cube. the start off good then about a week after i put them in the cubes the stems turn purple and the plants die whats happing and how can i fix it. also i have them on a heating pad and in the moister dome.

[LOC NAR on probation]

Rockwool could be too wet and pythium gets them.

The heat pad could be too hot once they are started

Or the dome is not vented enough.

When they die and the stem turns purple does it look like it's collasped ?

[tinytoon]

sounds like to wet but pics and more info would help. also toss the RW and get some Rapid Rooters if you can, they are much easier to work with