What encourages root growth(not soil roots, but above soil growth)? I have recently started a more agressive dosing regime. growth is great, no algae, but different stem plants have developed alot of hair-like root growth along the stem. It takes from the look of the tank. I have read before that this is usually related to a specific nutrient. On a side note, I havent prunned in a while, but I think its more than that.
I am sure several people around here should have an answer.

Good healthy growth of stem plants will include aerial root growth too. That is just how they grow. With some stem plants the aerial roots are well hidden - with Lobelia cardinalis-small form, for example. But, with most of them you just have to prune the tops off and replant them, and pull out the bases and toss them, to control aerial roots.

you can actually stip off roots, but what I was reffering to is ALOT of root growth. More than I have seen before at any time. We are talking bushes of roots.

I've read that aerial roots are caused by enough po4 in the tank water. It's a good sign so why bother??