Propagating String of Hearts
This is NOT the only way to do it. I'm just sharing the method that works for me.
Pot + Potting media
Prepare your pot. Do not use a large pot just for 1 cutting, even if it's long. If it is long and you want it in a large pot, cut it into several pieces before potting them up - SOH likes their roots to be snug in their pots. Usually I use 5.5cm pots for single cuttings.
For the potting media, I will usually use 80-90% gritty media with 10-20% commercial cactus/succulent potting soil (consisting mainly of peat). The gritty media I use will be porous, eg. pumice, akadama, pumice, leca, volcanic rocks, kiryuzuna.
Taking the cutting
Cut the stem in between 2 pairs of leaves, with at least 5 pairs of leaves on the cutting.
Remove the pair of leaves furthest from the growth tip, and cover the end with potting media, up to the node with a pair of leaves Try to lay the other nodes on the surface of the potting media, as they all have potential to root. Don't be worried if you see "stones" forming on the nodes - these are the tubers and they are the plant's stores. Those can take root if you lay them on top of your potting media, but don't remove them from the plant! Once they root, you can choose to cut the stem where it connects to the parent plant, and you'll have 2 plants (or more than 2). Nodes may also choose to send out roots first before forming tubers - mine prefers to do this.
Watering
Thoroughly wet the potting media, and drain out the excess water. Before you observe new leaves forming on the cutting, keep the potting media moist but not wet by watering once a day (but it depends on how fast the potting media dries - just don't let the media dry out for too long). Once new leaves start forming, it can be assumed that roots have grown on the cutting, and you can resume normal watering regime.
Light
Do not give the cutting direct sunlight until it has rooted, but when you put the plant into direct Sun, slowly acclimatise it to prevent sunburns.
SOH don't mind being in just indirect, bright light, but variegated ones will appreciate few hours of direct sunlight, and will turn pink.
About repotting
Repot when your SOH flowers, as SOH flowers when it is rootbound. You may choose not to repot if you'd like to admire the flowers, but if it's been a year, it would be good to repot nonetheless. To repot, remove all old soil, untangle the roots gently, pot into new pot(s)/potting media, and water thoroughly. Normal watering regime can be resumed immediately, since the plant already has roots.
