I have four Earthboxes, and yes, the medium does need to be moist in order for wicking to take place

I cant speak for fertilizer w. those, but w. Earthboxes, the 7-7-7 the kit comes w. suffices

Thanks. I'll water the mix thoroughly to start the wicking process.

You definitely need fertilizer if your mix is only peat and perlite. Self watering containers with that kind of mix also need agricultural lime to provide calcium and magnesium as well as to counteract the low pH of peat.

I do have garden lime, but have not yet mixed it in with the peat moss/perlite mix.

Is it best to use slow release fertilizer that mix in with the potting mix? Or should I fertilize by adding a liquid fertilizer to the water supply?

I also make compost tea to water my containers.And this year had to get kritter control. Everyone had trouble with coons-because fish oil in potting soil. I bought more self watering kits. Holds a gallon of water.