The purpose of the domes is to assist with germination. It does this by creating greenhouse-like micro climate conditions to help the seeds sprout faster. We highly recommend using the domes during the early stages of germination. These durable and reusable plastic domes are ideal to preserve moisture and protect your cuttings. As the seedlings or cuttings get older adjustments can be made to slowly reduce the humidity with the venting holes allowing your plants to slowly get accustomed to their new growing environment.