In DragonVale for the iPhone and iPad, upgrading the nursery will increase the amount of hatching beds you have to incubate your eggs. The more hatching beds you have, the more eggs you can raise at once.
The only way to upgrade your nursery however is by using gems.
2 Hatching Beds – 10 Gems
3 Hatching Beds – 25 Gems
4 Hatching Beds – 50 Gems
There are several ways to get gems in DragonVale. You can get them from gifting between your friends, from the Dragonsai Gem Tree, and from the Colosseum.
If you’re having a hard time getting gems, check out my other guide for how to get free gems in DragonVale.