Hi mate, They look lovely and on track see how your newer growth is a healthy green it’s a good sign there eating food and growing, I would recommend you now allow for a decent dryback to help set those roots into the new pots will likely be a few days 4-5 but don’t water just yet as Soil substrate need a wet/dry cycle in order to replenish oxygen at the roots.
I wouldn’t worry too much with the roots being broken apart plants are super resilient and will bounce back pretty quickly I will purposely score & break apart roots upon transplant as doing so will cause for lateral branching of the rooting & that’ll help them spread out fill out the pots, obviously overdoing it can cause a little stress & slow them down for a few days if there’s not already a strong rootball to begin with.
The yellowing of those lower leaves look like the plants used up some Nitrogen & Phosphorus from its stores, but thats could be likely due to a lower EC/PPM level in the previous pot, or its most likely that the roots are having a hard time up taking nutrients due to watering too frequently again refer to the first paragraph & always allow for a good dry-back between each watering.
As for your Temperature & Humidity based on your current levels your roughly at a 0.96 VPD which is a perfect level for the current stage of growth. Smaller plants/seedlings tend to like a 0.8KSP level until there root system and true leaves have established, then I would recommend keeping a 1.0KSP throughout the remaining veg period & increasing to 1.1-1.2KSP towards the start of flower, so on so forth. Download a VPD chart and follow religiously, as it’s what controls plant transpiration having it too low will cause the plants to uptake water & nutrients slowly & having it too high causes the plants to uptake water more rapidly and in turn they will pull in more nutrients, so it’s a balancing act but the charts available will give you a good guide to follow throughout all stages. Don’t allow it over the 1.5 as stoma’s will close and plants the won’t transpire.
If possibly try and get your Temperature to around the 26-28 range & and increase the humidity to 65/70% should put you in that 0.9/1.0KSP ball-mark, the increase in temperature will also help with the pots drying back faster & the plants will no doubt be much healthier overall as they tend to thrive in hotter & a more moist environment.
Download something called Photone off the app store and use this to guide you PPFD levels which is basically how intense your lights are. Around 250/300 PPFD is a great number for early veg, you can increase as they get further in topping out at around 450/550 mark towards the last week of veg before you flower, once in flower these levels will increase further and by weeks 2-3 your aim will be around that 900PPFD range for optimal growth without co2 supplementation. Hopefully some of these fundamentals can help you🙏🏼
