(SOLVED) Truffle worm farm not working. Why?

[Dowlphwin]

http://images.akamai.steamusercontent.com/ugc/447330122532147238/1BC986C41815C8CD6B27328B6104405A30D5EBD6/

Looks a bit crude, but I bit by bit converted a different type of farm, but nothing helped. I now have mushroom biome background and music when standing at the dedicated position, yet from the mushroom grass blocks left and right outside of the screen there are no mushroom biome enemies spawning. Do I have to further overwhelm adjacent biomes (snow, hallow) even if they only become active if I move off-center a lot?
There are tons of regular cavern enemies spawning, e.g. bats in the empty space below. But haven't seen a single mushroom creature there - ever.

I also lowered the ground below more and more because there were tons of creatures spawning there. Maybe still. Dunno, maybe they fall out of the sky.

[Tealtyr]

Is it underground?
Underground and aboveground mushroom biomes are two different things.

[Dowlphwin]

It's underground. Pretty much half of max depth. Might even be cavern layer.
I have a tiny attempt of a farm much higher, and that one does occasionally spawn mushroom creatures.

[Dowlphwin]

I'm wondering whether the adjacent biomes (snow left, hallow right) override the mushroom blocks despite them being ouside of the screen and mushroo biome active where I stand. But I don't get hallow creatures on the other side and as I said, it's mostly just regular cavern stuff.
Maybe I've just selected a bad spot. But no one talked about that in the guides.

[Dowlphwin]

I got a natural mushroom biome though, relatively small, and pretty much surrounded by Hallow, and it's spawning mushroom creatures.

[Nuggz]

It could be you are very unlucky. I made a Mushroom Biome just 100' below the surface, and its surrounded by Crimson, Corruption and Hallow but it still spawns the Truffle Worm. I just kept going up and down through the farm until it spawned. If you have the item that tells you what enemies are near, the 'Rare Creature' message will change to inform you when it appears.
Edit: Also, try using Battle Potions and Water Candles in the Mush farm, the worm classes as an enemy so it will increase the chances to spawn one

[Dowlphwin]

Gaaah, it was a really hidden problem, but my fault: The mushroom wall is of course not natural! There couldn't have been spawns on tiles with artificial wall.
What also seems new is that truffle worms will die on contact with any hostile creature. I'm currently experimenting with putting an additional layer on top of the spawn layer that only covers the visible space, hoping that spawning worms will crawl under it before the next spawn kills it.

[ciceqi]

The truffle worm has been damageable by other enemies as long as I can remember. What I ended up doing was making three long rows of one-block high mushroom grass and taking a Death Sickle with me--which it looks like you have! When I saw a worm, I'd go on one of the other levels, kill off any enemies next to it through the ground block (which apparently didn't alert the worm to my presence), then jump down with the net at the ready and start running. I also went mostly-offscreen every time I cleared it to encourage things to spawn again, which seemed to work pretty well.

[Dowlphwin]

What also helps I think is not standing in front of a wall. Some types of enemies don't spawn when the player is in front of a wall.
I still had some trouble though because above my worm farm was some open space for other farming purposes, so there enemies spawned, too. And after a while, nothing spawned at all, which was weird. There must be certain no-spawn phases.
But even an inefficient worm farm yields plenty of worms. After all, one usually doesn't kill Duke Fishron more than 20-50 times.

[Sam Vimes]

I know this is an old thread, but I found it (high ranked Google hit), and others might. I was having an issue with my own truffle farm. I thought I'd be clever, and made rows of mushroom grass blocks with just a single empty space between the rows. I figured the truffle worm, being only one block high, could spawn in those spaces, and other enemies wouldn't have enough room. But the Terraria Game Gods must have thought of this, and decided not to allow it. Truffle worms only appear to spawn when there's enough room (a few empty blocks above the grass) for other enemies to spawn there too. I haven't seen this restriction documented anywhere else so far; it just appears to be true from what experimentation I've done.