How to prevent enemy spawns in an artificial jungle biome?

An artificial Jungle biome can be created by planting enough jungle grass in one area and letting jungle vegetation grow. Is there a safe way to do this without having enemies spawn? For example if I want a jungle grass farm, will I be safe if I just provide background walls and enclose all the jungle grass, or will the artificial biome extend beyond the walls and allow jungle enemies to spawn outside? How far would the artificial biome extend?

Note: This question is specifically about jungle but may apply to all biomes in general.

4 Answers

If you want to prevent enemies from spawning in a Jungle biome (artificial or not), build several houses and have NPCs move into them. This is the only reasonable way to fully stop hostile mobs from spawning in general.

Note that during Blood Moons enemies will still spawn, even with NPCs nearby.

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From my experience in playing with Terraria, when you create an artificial biome, the game will treat it as if the biome "exists" to begin with.

The problem with walling your artificial biome is that, the jungle seeds will be unable to "grow". The artificial biome would grow the size you want it to be.

Here is a guide about gardening that could be relevant to you:

If you notice, the objects were grown according to how they are found in the wild, while creating an enclosure to make it easier on you to get the items.

According to the Terraria Wiki, to keep enemies from spawning, or a least very rarely, move in lots of NPCS, and if you have the 1.13 or past put out Peace Candles along with a calming potion if you're near the biome, but remember, Calming Potions only work for a limited time, when Peace Candles only work when your in the range of it and it's placed on a table or crafting bench. Or yes you can but walls to stop spawning too. (I'm taking the text and saying it in my own word for the wiki.)

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This is based solely on the fact that it worked once. I needed to be able to farm trees constantly so outside was dangerous. How I made it work is I built the bottom half of the area with stone and the top half with glass allowing sunlight in. The trick was the glass was several layers thick. Starting from ground level and working down. It is realistic but I only bothered to do it once. Over a year ago.

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