If you have a Layer 3 switch, or any switch that supports VLAN and 802.1Q you can create additional LAN networks that can be individual /24's.
I wouldn't suggest using a LAN block larger than a /24 as you can run into performance/stability issues with broadcasts overwhelming all hosts on the network. Instead, carve up that /22 into multiple blocks like so:
192.168.0.0/22:
192.168.0.0/24 - 192.168.0.1-254
192.168.1.0/24 - 192.168.1.1-254
192.168.2.0/24 - 192.168.2.1-254
192.168.3.0/24 - 192.168.3.1-254
This will also give you the ability to segment your network, and will make overall management easier. You can even split those /24 blocks into smaller network blocks so you can keep servers, management IP's, VIP's, VPN users, etc.. separate and firewalled across LAN's.
For example, with the blocks above, we want to further segment the first block.
First split them into two /25's:
192.168.0.0/24:
192.168.0.0/25 - 192.168.0.1-126
192.168.0.128/25 - 192.168.0.129-254
Then we can split the second block into two smaller, /26 blocks:
192.168.0.128/26 - 192.168.0.129-190
192.168.0.192/26 - 192.168.0.193-254
Yes you 'lose' a few IP's in each network for subnet, broadcast, and gateway IP's, but overall it's a great solution to optimally use your IP blocks.
Hope this helps!