Man that thing looks lonely under there lol.
Rockwool is great (and not so great) stuff. It holds a lot of water so, as was said, under a lid, won't need water for a very long time. It also holds a lot of air so if it isn't constantly sitting in a puddle it is relatively hard to overwater.
BUT...the pH can fluctuate quite dramatically. Even if you soak it in acidic water first, it can still rise very quickly.
I keep a close eye on it at first by squeezing out the excess water and checking it's pH daily...or just by gently squeezing some water out and then pouring/leeching pH corrected water over/through it then gently squeezing it again before putting it back.
Squeezing rockwool isnt that great for the rockwool and can be hard on roots. Be careful. Spinning water out is better but...just be careful and gentle and you should be just fine.
So, as your seedling sprouts, you can start gradually opening the lid..like a bit more each day. Once the lid is mostly or completely removed the cube will dry out much more quickly so keep an eye on it. Won't be long before it's time to transplant anyway though.
Even with feminised seeds (and ESPECIALLY with normal seeds) it's a good idea to plant more than one. If you HAVE more than one that is. All kinds of reasons for that including sex, phenos, redundancy....
Have fun and good luck.
PEACE