Few weeks ago I tested the drip irrigation system indoors and it worked pretty well. I've modified it a bit, I used the solar panel and pump that i purchased last year and an aquarium 2-way valve to control the water flow. The solar panel powers the pump and the valve control the speed of the water drip. Don't worry if you don't have the solar panel and pump, the idea is still the same and it'll still work. You just need to make sure the water source is placed higher than the plant.
I used the solar panel because I wanted the watering system to work only when the sun is out. This way I can prevent the risk of over-watering the plants. Since i planted mostly drought-tolerant plants this year, I only put the drip on two plants that needs consistent moist soil-Mandevilla and the Fairy Rose. This system can be expanded to water more plants but I'll keep it to two for now.