I had a similar issue with the height too. I think in the end it was a combination of
1-not enough good quality light....i used cfl's to start them off with, the most powerfull ones i could get just couldnt cut it. the problem with not getting the right amount of light early on is that the plants usually stretch, grow too tall too fast and even though this is kind of repearable it still stresses the plant which slows growth and vigour.
2-settling into a fertilizer routine......its taken me 2 months of trying different stuff to settle on a combo of seasol seaweed concentrate and seasol powerfeed fish concentrate. both organic and finding they improve pest resistance, plant growth and vigour. Anyway the plants seem to love them and there both cheap from bunnings or most of the other ozzy garden centres.
3-starting with the best quality soil and additives you can afford.
If its one thing ive learnt from gettho gardening on a budget is if your gonna spend fuk all on everything at least buy good soil.
i use a mix of the stuff i can get my hands on, not always what is the best. Buy at least a good organic compost/soil and a bag of vermiculite to help the soil drain.
ive also tried mulching the tops of the pots with pine bark ($5 from buy-lo) and it seems to be helping the plant.
For this grow i am not using any forms of pest control chemicals. ive got a few praying mantis that have made their homes on my girls and there brilliant sentinals against the other insect pests. i think ladybugs also prey on the smaller aphids but leave the plant alone so once again id encourage them onto the plant rather than getting rid.
just thought id share some of this as it happens. I AM NOT AN EXPERT and maybe through some of my trial and errors i can share some info, otherwise all suggestions for my grow are welcom
peace growers