Why can't I create default mushroom underground farm?

Cap'n Catman, there a couple guide around that show you how to make underground farms, take a look at them. the method I use is to get rain to fall into a hole in the ground that leads to a chamber; eg. a 3x3 underground chamber with a hole in the middle will eventually create a 8 slot farm (memory is a bit sketchy though so you'll have to test it) keep in mind if you don't want grass growing in your new underground farm you'll need to put anything other than dirt underneath the hole, clay will do if you have nothing else and don't feel like making a fancy thing.
Hope this helps!

How do you flood them? So plotting land near them won't work?

Finally! Also blue rocks!

aww damn ive been waiting forever for a mod like this and now that ive finally found 1 it has blue plants :( i hate blue

By flooding them. But you only need to do it once.

Do the plots need to be watered? If so, forgive my simple question, but how in the world do you water the plots...??

Ok cool, so it should be a nice way to steel produce food even on winter huh :)

(ps : thanks for all your mods and your work, i really like to see ppl trying to make this game better, unfortunately there is not so much ): )

Underground plants grow day and night all year round.

hi thanks for your mod ! but does they grow in winter too?