Do not replace the cover until the leaves have dried somewhat. Open terrariums need occasional watering, but not as often as other houseplants. Waterings should always be light. Heavy waterings result in too much standing water. It is better to be a little too dry than too wet.
Many plants outgrow their neighbors or the terrarium.
With a little trimming these plants can be brought into bounds. Frequently pinching out tips before a plant becomes too tall will result in more balanced growth than infrequent, more severe cutbacks. Do not plan to fertilize for at least a year after planting. Occasionally it may be necessary to replace plants. Follow the same directions and precautions for adding new plants to the terrarium.