Celery Granada

I've just sown some celery seeds but it's just occurred to me that I don't know if it's trench or self-blanching. It says nothing about it on the packet or in any of the descriptions I've just looked up on the web. Do I assume that if it doesn't specify, then it's probably self-blanching? If so, would it matter if I were to treat it like trench celery and try to achieve some extra blanchiness? I've never grown celery before!

No, absolutely nothing! It doesn't mention anything about trenches on the instructions so I'm guessing it must be self-blanching.
The previous tenant on my plot left behind several lengths of thick plastic tubing (about 4" wide and maybe 8 - 10" long) which I thought would make good blanching tubes.