i got that a bit muddled

if you are getting elongation, you need to increase ventilation and may require more watering

you can also fix this with more light but if the light brings too much heat you get a reduced benefit

it's not just the growth rate of the cells, it's also the liquid/gas solubility of CO2, at lower temperatures CO2 is more concentrated, first, and second, it dissolves better in the water of the cells of the plant

i am not sure i have articulated the principle well but less light gives less elongation with lower temps, and it's probably really related to CO2 and growth acceleration too

you can reduce elongation, probably, by increasing CO2 levels in the growing area