The Swamp biomes in Valheim are full of danger and hazardous conditions. They also have a low yield of resources, but several materials are still exclusively farmed in these boggy wastelands.
Swamps appear as muddy, camouflage-like patches on your map, and they are filled with just that. Get ready to traverse mucky, boggy ground obscured by gigantic trees and tons of threats — most of which are toxic.
Resources
It is possible to harvest Thistle within Swamp biomes, though you'll likely have a better time of it in the Black Forests. Resources exclusive to the Swamp biomes include Ancient Bark, Scrap Iron, Guck, and Turnip Seeds.
Ancient Bark comes from the gigantic trees which grow in these boggy biomes. The bark is used to craft Viking Longships, Bonfires, and several advanced weapons such as the Draugr Fang bow.
You can find Scrap Iron embedded in Muddy Scrap Piles, usually blocking passages within Sunken Crypts (which we'll cover in a minute). However, after defeating the biome's boss, Scrap Iron can also be detected sunken beneath the murky Swamp floor using the Wishbone. These scraps can be melted down and recycled into fresh Iron ingots using a Smelter.
Guck is gathered solely from Gucksacks found high in the Ancient Trees of the Swamp biomes. You will need to build a staircase up to where they are stuck on the trunks and branches in order to farm them. And you will definitely want to engage in this endeavor if only to get the Guck required to craft the Draugr Fang.
Like Carrot Seeds in the Black Forest, Turnip Seeds can be cultivated from flowers growing in the Swamps. Plant these back at your base to grow one Turnip per handful of seeds. In turn, Turnips can be cooked into Turnip Stew.
Chests found within the Swamp biomes contain most of the same loot as elsewhere, such as Amber, Amber Pearls, coin, and Ruby. Additionally, they have a chance of spawning a few other items, such as Ancient Bark, Chain, Iron Head and Poison Arrows, and Withered Bones.
Sunken Crypts
Akin to Burial Chambers found in other biomes, Sunken Crypts are the only structures you will come across in the Swamp biomes. They have an iron gate that must be unlocked using the Swamp Key obtained from defeating The Elder. Muddy Scrap piles block most of the passages, but they are easy enough to clear by mining and will yield Scrap Iron, Leather Scraps, and Withered Bones.
Threats
Not only do the inhabitants of the Swamp biomes pose a threat to your survival, so to does the weather.
Conditions
It is always drizzling in the Swamps, accounting for its boggy terrain and sunken treasures and tombs. The eternally dreary weather means you will constantly be sodden and forced to combat the "wet" debuff on top of the inherently hostile beings that dwell within the Swamps.
Bring lots of Poison Resistance Mead and extra wood for a makeshift shelter, and fire to dry off.
Monsters
Every creature you encounter in the Swamps will be hostile. The Swamps' inhabitants are Blobs, Oozers, Draugrs and Draugr Elites, Leeches, Skeletons, Surtlings, and Wraiths.
Blobs and Oozers are both susceptible to blunt and frost damage. Skeletons are weak to blunt damage, Surtlings to frost, and Draugrs fall prey to spirit damage. This makes the Frostner war hammer a great weapon for most threats you'll encounter in the Swamps. The majority of the creatures here are resistant to fire and poison.
Draugr and their elites drop Entrails upon defeat, which are used to make Sausages in a Cauldron. These are a fairly nutritious meal when measured against all of the meals available in Valheim, so Entrails are well worth the effort in gathering.
Likewise, Leeches will drop Bloodbags used to make the most nourishing meal available, Bloodbag Pudding. They are also used in brewing the mead bases for Medium Healing and Frost Resistance, which you will need in order to last long in the next biome.
Once you've had your fill of the Swamps, it's time to summon and defeat the biomes' big bad, Bonemass, then prepare to hike into the Mountains to conquer Valheim's most elevated biome.