dont think this is a problem but can you let me know what you think please

guys am in the uk growing big bang fem from the greenhouse seed bank in holland.

my question they seem to be growing very stocky and bushy like 5" high and 8 wide is this the norm they are under hps light and are in a 6ft nft system.

the plants look great nice and green and have no problems but they do seem very short i might add they been under for 2 weeks now and am using canna nutes witha ph of 6.0 and a EC of 1.2 at the minute

any replies appreciated