My 3rd year starting SP - have never bought "slips". Doesn't work well to cut potato before putting in water, though I did get a few slips. Wasn't happy with "lay them on their side in potting soil", though I got a few. This year I put whole potatoes in water - "pointy-side down" - think you're a gardener .... good luck on choosing stem end from
root end, LOL. Some were organic from grocery and some not, but they ALL know which way is up!
Much better slip production this year, though some were making leaves underwater, OOPS.
After some good growth and/or roots, I carefully cut out small sections for viable life and suspended them in water. Things are going well!
The main thing to know is that this process takes MONTHS. I've got huge, warm, South facing windows ... something to be playing with during Feb in Zone 3b-4. Somehow, I get aphids in the house, and these are the "canary in the coalmine". I was potting last week and sprayed with OMRI
soap - all good for now after 1X.
My biggest problem in this zone is giving them
enough days. I've only gotten long and twisty 1inch roots because I put them out rather late and have had major grasshopper pressure.
This year, I will put them out earlier in black grow-bags with cloches, black-painted water bottles, and tight row covering.
Wishing all of us a great 2021 season .... I will post update on my SP.