Underwatering ? Please help me save them

some plants will uptake quickly. some spils wont let the water soak the medium if watered too quickly. i usea 500ml plastic syringe to water slowly. its like a giant medicine syringe and it helps me water slowly and efficiently over the spots that need it as to not become hydrophobic. i can also feel a difference in the weight of the pot when watered this way. less runoff and more water

Wayer plants very slowly. Water until you get runn off. Let pots completely dry before watering again. Make sure you dont give too much light right away. Slowly raise the light intensity over several days so they get use to the light.

Proper habits will avoid this. Water entire pot - however much it takes. NEver leaves a dry pocket in the substrate. If soilless, should be fertigating every irrigation with 10% runoff. Minimal runoff with soil is fine. Wait for top layer to dry and repeat. If you do this at same loss of weight, it requires the same volume of water, so it is predictable. How much dryback you allow is up to you, but obviously don't wait until it wilts. definitely need "something" to handle the excess water. the pot elevators that fit nicely into drip saucers are good to use.