Hello :)

I have a mandarine tree which has bloomed last year and the fruits were ripen. It is in a container, which has a new soil, it is not clogged, the roots are okay (white, pale yellow; some of them are dry).
It has overwintered in 5 Celsius, inside and it had light, but in January all of the leaves dropped and the branches on the tips started to brown which I cutted because I thought it will go away, but it has spread to all of the tree. The tree, with the rest of the citruses, is outside on the sun for a month and a half now, we have temperatures above 20 Celsius right now for 2-3 consecutive weeks. When i scratch the surface of the bark, somewhere it is very pale green and somewhere its very green, so the tree is alive. When I cut the tips of the branches, it seems like white/pale green color (almost like its dry).

Also, my orange tree is vivid green, has new shoots of leaves coming out, and it is in the same circumstances as the mandarine tree, but it has pale brown branch tips which is emerging (even when I cut it). Can you tell me what the problem is? Orange tree has the same problem as one of the lemon trees. When I scratch it, it has green color inside on the beginning, but after few days, it has dark yellow/pale brown color (like the ground is too moist, but I dont think it is). The problem is that it is in a plastic container and the bottom of the container cant dry as the top can (I cant buy teracota right now), I try to turn the soil twice a day with my hand. Also, the citrus trees have no root ball per se, but it has dispersed roots (it is not clay-bound like it is when bought). One citrus is clay-bound but it has the same problem as the orange tree). Is it really that the soil cant dry up fast enough??