Humidity
Humidity.
Whilst in the flask, the plants are accustomed to 100% humidity and therefore the leaf does not develop a complete protective layer of wax (cuticle) which normally reduces dehydration. During the weaning stage enough humidity must be provided to protect the plant but it must be less that 100% so that a wax layer will be produced within 2 or 3 weeks. You can place the plants under covering with plastic and practise by fogging or misting. The plastic should be removed slowly over a 6 week period.