Just up your dosage a little then? When I used 5 gallon or even 3 gallon fabric pots, I would water once every two days until they demanded a daily watering, but they never required more than that. I could see if you had a big plant in a small pot, but that would be more of a demand for moisture than nutrients.
Right now I'm growing 6 plants in a 2 x2 ft bed covered ion panda film. They have plenty of coco to dig around in, and it stayed moist for much longer than in fabric pots. The plants doing fine. I went three days without watering them last week, but I think that's pushing it nutrient wise. Every other day seems perfect.