I'm sure they are about to stretch mate, 1" between nodes is ok IMHO. Now is the time for them to kick in.
Now I wouldn't usually say this bc of my knack of being wrong but I'm convinced it's a watering issue. The leaves look nice and green but puffy. When you think it's time to water, give it another day or two.....if you dare lol. I used pots like yours for first few grows, I have one now with a smallish plant in and honestly haven't had to water it more than a few 100ml every 3-4 days, even my airpots don't need lot's and for me to get 10% run off would be overwatered in my situation. Not sure of your temps, humidity etc but where I live in the UK, it's winter and cold.