How difficult is it to make a raised planter box for herbs?

[[DHT]Osiris]

Plastic liner?

Sure, that can work, or cedar

 

[Greenman]

Plastic liner?

Those are available, you just have to build a planter that fits the liner. All my planters are for appearance, so I'm locked into cedar. Though the simple reality is they have to be pressure washed every couple years if you want to keep them looking good.
I've looked at using white oak because I can get it cheap, but ripping down 8/4 by 8 oak into 3/4 stock takes an expensive band saw, and produces a metric shit ton of sawdust. Those 8/4 boards also really heavy.