I just soak pots like these once or twice a week. Sit them in a bucket of water for 10 minutes or more to allow the water to penetrate into the centre. That soak, along with better watering, will keep them going until you can safely repot.
Better watering will also help. Just watering each pot until water runs out the bottom is not watering effectively. Dry mix and/or root bound actually repels water so the water does not penetrate far, it just runs round the edges and out the drain holes. A second watering will help. The first will soak in a short way. Watering again a few minutes later lets the water soak into the damp part and then further to the centre. I have heard that Japanese technique is to water each tree 3 times. That would make sure the water is effectively soaking right to the centre of the pot.
To effectively water my potted trees I go round once and give everything a good soak then water each tree a second time to allow the water to soak in properly. In hot weather I do that morning and evening to keep up with the need for water. If any trees are still wilting they either get a weekly soak or get a shallow tray of water to sit in.