Doesn't the soil just drop through the bottom of those holes? What's the feeding and watering plan, sorry I've come late but it looks a great idea from
@myke
Nope. Only plan is keeping the reservoirs full of water and that's it.
Feeding, in my experience with SIPS, is simply top dressing, moistening aforementioned top dress, and then continuing to keep the reservoir full itself.
Sounds "abnormal", but when you think about it this is how plants grow naturally. Consider a plant buried in the ground that you water. Eventually, the water will follow the path of least resistance through the various grains of sand/rock and eventually "pool" up somewhere. This "pool" of water is accessable by the plant's roots, but said roots aren't submerged in the "pool" forcibly either.
Plants, like us, don't want to wait until they're dehydrated. We as humans don't wait until we're out of water to go the store and pick some up, we usually have some on hand and can even just drink tap water in a pinch if we're fortunate enough. Point is, we always have water accessible to us at our own convenience.
Give plants that same courtesy and you will be immensely rewarded.
I've only ever used "swicks" myself as opposed to full blown SIPs, but
@myke pictures of those roots speak for themselves.
Fact is, 90-95% of issues plant growers face is related to watering in some shape or form. By growing plants in the ground, or in SIPs, you effectively eliminate watering as an issue and will automatically experience more success than anyone growing in pots.