The pots are a bit big yer but more soil dosen't equal stroger nutes - a handful or a bucket full if the soil is 10 10 10 NPK strength then thats as strong as it can be. Heat stress can bring on nute burn as the plant dosent respond well to high nutes at high temps, this makes it get very hot inside the leaf and processes start to shut down. What i have noticed is that a lot of soil is very hot for plants and has nutes that last easily 5/6 weeks in a reasonable size container, companies think more nutes equals better plant growth but there is a fine line between the two and overstepping it leads to disaster. I too use to be keen to reach for the nutes but now its what i manage to do without for most of my grow and especially in veg as a lot of other members are saying. I use my nutes to correct deficiencies not feed my plant.
You need a seedling soil for seedlings and start of vegetative growth, my grow and soil is not the same but our principles are so find a soil and work out how long the nutes in the soil last for a certain size pot that would hold the plant and roots to the point where they have spread through all parts of the soil and plenty are sticking out the bottom. I make this point the end of my veg period so the plants have been in the soil 5/6 weeks no nutes and the roots are starting to get a bit root bound, any deficiencies in week 6 will be cured with fresh soil and a bigger pot so i transplant and place in the flowering room in a pot that will just be getting a slight bit root bound by the end of flowering. Now my flowering takes two weeks 12/12 to show the first flowers and a futher 8 weeks or so to finish so thats almost two and a half months and the roots are getting through the nutes in that bigger pot in about 6/7 weeks. So week 7 i give a light dose of ferts and at most maybe one more slightly stronger one in a week or two but after that all i got to do is a light flush at week ten of flowering and its chop chop time.
So if you do find it is the hot soil and confident the temps, drainage, watering and humidity etc etc are ok then there are things you can do to make life easier which won''t cause any major drama. You can mix the soil with somthing like coco fibre which contains no nutes to weaken the overall soil mix, even buy a very light soil to mix with it. I have used my seedling soil mixed with my flowering soil with plants in flowering to make a less hot soil. As long as the soil isn't miracle grow then you can use the watering times to administer light flushes although wait till the plant grows a few roots first, simply, slowly and gently water enough water so you get quite a good drianing out the bottom, do it slowly and take your time as you don't want to make the plants swim. The point of choosing the right pot size is that you get one that dries out in say 5/6 days so the roots can cycle between wet and dry periods reguarlly, too dry and root hairs die, too wet and root rot sets in. You got to look after your roots more than the plant itself, learn how to cultivate the roots and what they like too.
Thank god you don't have bugs because they are the worst problem i have ever had. Those air pots look wicked and bet you would get great root growth outa them with right size pot and plant. Keep us informed of the out come of witholding the nute, guess you won't see signs or recovery for a few weeks, maybe sooner if the flush has worked.
nly the top soil is dry it is nicely moist undernieth