At times you will have Cryptanthus pups where the leaves will fold back upon the base of the pup making it impossible to plant the pup correctly. The plant is trying to slow down evaporation by rolling itself into a tight ball to conserve moisture. There is only one cause, lack of humidity , but it occurs in a number of ways:
1. When the leaves fold back down on to the soil they act as levers and lift the base of the pup out of the soil, then continue to fold down eventually forming a ball. Problem may be not enough water but definitely too low a humidity in your propagation area. (Plants will grow in conditions where humidity is too low because their roots are replacing lost moisture.) If you can strike pups in your Cryptanthus growing area (without them turning into a ball) it is an indication that you are growing the plants under satisfactory humidity levels.
2. When man or mice knock the pup out of contact with the soil (where you have maximum humidity levels) the pup will dry out and curl into a ball.
3. Obtain a pup and when you get around to potting it up you find it has curled into a ball. It means it has been transported or held in too low a humidity. Wrap the pups in newspaper, wet the lot and transport in a cardboard box.
Once you have your Cryptanthus pups in or approaching the fetal position, you cannot pot them up until you straighten them out. You can solve the problem by submerging the pup in water for a day then storing it in a standard 200mm pot half filled with very wet mixture and if you want to maximise the humidity level, cover the top of the pot with Glad Wrap, punch a few holes in the Glad Wrap and soon the leaves will straighten up and the pup can be planted normally.
Established Cryptanthus have a way of indicating when they are happy with the humidity by how close the leaves are to the top of the potting mix. They should not be hugging the soil like a second skin but slightly up. Watch the leaves in the morning, after watering, during very high humidity days, during rainy periods. You will gradually come to understand when they are happy. A couple of things that may confuse the issue - in too low light the leaves will point to the sky as if surrendering. Sometimes the leaves are held off the soil by the rim of the pot even when the humidity is too low.
In winter, Cryptanthus leaves do not like to be wet during the night time. If you have a Cryptanthus fosterianus (or its look alikes) you will find (by feeling) that there is a thick rib down the entire length of the leaf. During cold weather, water drops on this portion of the leaf causes the cells to rupture creating a dead spot that is like a dimple (concave).