The cold will cause issues, but not that significant. How cold was it for the first few weeks? These are at day 17 and have been in 40-65f in the tent since birth which is way out of the recommended range. They are popping out their sixth/ seventh node. Id say lack of light and inadequate watering is the main issue here.
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Just thought I'd post this ad cold can be an issue, but won't usually bring a plant to a standstill. I'm going on 6/7 nodes in 18 days.
Just waiting on a heater ATM. Would be doing far better at 70-85f.
On another note, roots dont chase dry medium..watering around the stem will only lock roots to a small area in the pot. .when you water you want the whole pot moist, and as it dries from the top down, the roots will chase the moist soil at the bottom of the pot and branch out. The worst thing you can do is water around the stem and lock the roots into a small ball.
Overwatering doesn't come from too much water at one time, but more often too frequent watering, especially right around an underdeveloped root ball. Watering one spot in the pot will cause hydrophobic patches with pH spikes in the medium and lock the roots into the small ball of moisture you are providing. I can root out the bottom of a 3 gal pot in 20 days if I water the whole pot, or I can lock roots in a tight tiny ball in the same pot by watering around the plant only.
Water your pot properly and the roots will branch out. There are two types of roots, smaller roots which thrive in the drier top section of the pot, and wet roots which will chase the moist soil down the bottom. If you aren't providing proper watering and wetting the whole pot, the wet roots won't develop and head for the bottom of the pot.