In terms of design, this product is great. It's very convenient that you can have 3 levels to water everything from the top. The ventilation is also good. However, there is a serious problem: the seeds germinate much faster and the seedlings they produce are much more fragile if the process is done in the dark. It's like day and night (pun intended!). The only solution is to keep the seedling hidden in a closet or in a permanently dark space, but it would have been much easier if the manufacturer had simply thought to use non-transparent material. To monitor the process, a small window would be sufficient, or at least it is definitely preferable to just lift the discs to see, rather than having to bury the seedling.