Having been removing the lid of the germination box for extended periods in May, the Dypsis psammophila didn't cope as well as most of the other palms in the box with the lower humidity, so I have decided to leave it a little longer before trying this again. There is still plenty of time before the plants will need to come out of the box, so I will try it again when they are all a little larger. Most of the other species coped OK, but I don't want to take any chances, when it is not really necessary at the moment. There has been continued growth despite the dislike of the lower humidity, so I don't anticipate any ongoing problems.