Watering and run off

Do I really need to water until I get run off? I’m using 22 litre pots and growing organic.

Technically no, but if water isn't making it to the very bottom of the pot, the roots will not either.

Best results are had with mostly dry soil being watered every few days. Easiest way to protect your plants from pH problems, root disease and nutrient issues. Water conservatively, even if it means more, smaller waterings. Also gives you a chance to see each plant more often for quality inspections! Also if using liquid nutrients, mix weak to start! Happy growing!