Can I use all purpose soil for orchids?

No, you should not use all purpose soil for orchids. All purpose soil is designed to hold on to water and is not good for orchids because the roots will rot. Orchids need a potting mix that drains quickly and does not hold on to water. You can buy pre-made orchid potting mix, or make your own either with sphagnum moss, perlite, and bark chips.