Induce stretch in a short plant.

a parte che deve ancora partire come ti hanno detto gli altri cmq io spesso utilizzo bud ignictor di advanced nutrient all'inizio fioritura e mi aiuta ad allungarle un po ma nel tuo caso non fare nulla piccola e cicciona cosa vuoi di piu???? e cmq vedrai che si allunga

I also suggest moving your light further away from your plants. Beware of the flower stretch though. Good luck!

I wouldn't worry, it will stretch when it goes into flower if not, it happens sometimes do to genetics i had the same thing happen this last run with my LA confidentials, one did get to big, unfortunately it took a turn for the worst but yours looks super healthy, I would count it out yet, seems like your light is a far distance away so I would say genetics

If you want the plant to stretch more, move the light source further away/turn down the brightness. Of course, this will effect all the plants in the same tent equally. This is basically your only option as the plant height is 90% in the genetics. You have a Sativa (which generally grow tall) next to an Indica (short and squat). This is actually the main reason why many people prefer to run all the same genetics/clones in a single run, as it makes it far more likely that they'll all reach the same height around the same times. You could of course train the taller plant not to grow any higher using LST or HST. This is probably your best option.

It still needs a preflower stretch it's comming, seems like it's a tad immature still.