2 first replies are spot on.
The pots are bit small and might dry too fast.
At this point I'd suggest you just water it more often, like every 3-4days to give it some dry back,
but since it's fabric overwatering is more rare problem than drying too fast.
When the soil is too wet or dry, the plant can't utilize the nutes in there.
So increase the nutes a bit, and keep the medium consistently moist, keep an eye for the reaction for the treatment.
Can't really have too much runoff unless it stays in the puddle.
When it has saturated the soil with nutes (to strength of the fertilizer solution),
rest is just wasted water/nutes.
Also if parts of the soil get too dry they take some time to start soaking in the water,
often it just flows over and goes thru sides of the the bucket.
So ya could try giving the fertilizer slower and give it some time to soak before giving the rest.