I have a 7month old long haired male dachshund and his hair hasn't grown yet,could you please tell me at what age does it grow?  Thank you

Can''t really answer your question but have seen youngsters in show junior classes (12 to 18 months) who have not yet got a full coat, so would guess somewhere between 10 and 18 months and probably around 12 months.

They really don't get their full coat until about 2 years of age.
My youngest boy is now 16 months old and he has long hair in parts!  His ears are lovely, and his tail is magnicicent, but the hair on his body is not very long.  They seem to go through an untidy stage, as their hair grows, but once it is fully in it hardly needs any grooming.

Good luck with your Puppy