Underwatering

What's happening

Adansonii's thin leaves hold little water, so when the soil dries out completely the plant can't keep its oldest leaves hydrated. Those leaves yellow and go limp, often with crispy edges, while the soil shrinks and pulls away from the side of the pot.

How to fix it

Water thoroughly until it drains from the bottom. If the water runs straight through bone-dry soil without soaking in, bottom-water instead: set the pot in a few inches of water for 20–30 minutes, then let it drain fully. Going forward, check the soil weekly — a chunky aroid mix dries quickly, so this vine often needs water a little more often than a deliciosa.

This is general guidance based on common symptoms; individual plants vary.