Add netherwart on soulsand, regular musrhooms underground (20 or so), cactus and sugarcanes also work great like this:
WWWWWWWW
SCSCSCSCSCS
CSCSCSCSCSC
WWWWWWWW
W:water
C:cactus
S:sugarcane
Remember to plant on sand WITHOUT the cropsticks
Also 20ish melon/pumpkins each works too, got my altar...