Subnautica Ghost Weed — Where to Find It and What It's Used For

Ghost weed is a bioluminescent deep-water plant in Subnautica that most players first notice glowing pale green in the Lost River and the Blood Kelp Zones. It isn't a base-building material or food — its real jobs are endgame: the seeds are a component of the Hatching Enzymes used to cure the Kharaa bacterium, and a solid backup fuel for the Bioreactor (70 energy per seed). This guide covers every spawn location, exactly how to harvest it for the maximum seed yield, and why you shouldn't skip it on the way to the story finale.

Here's what you'll learn:

• Every biome where ghost weed spawns
• The exact knife-harvest math (9 seeds per plant)
• What ghost weed is actually used for, endgame included
• How to stockpile seeds without destroying the plants

Official resources: Steam store page · Official Subnautica Wiki — Ghost Weed · IGN Subnautica page · Wikipedia — Subnautica

Per the official Subnautica Wiki: "Grows exclusively in deep waters where its pale pigmentation is visible on the fewest wavelengths." The databank entry reflects the plant's real role: it only grows where almost nothing else can.

Where to Find Ghost Weed

Ghost weed grows in four deep biomes, with the Lost River by far the densest:

The Ghost Forest section of the Lost River is the community's standard farming spot — several plants grow in the brine pools there, and the biome is on the route to the kyanite lava zones anyway, so you harvest en route rather than making a dedicated trip.

How to Harvest Ghost Weed

You can't pick ghost weed like a mushroom — it must be cut with a Survival Knife or Thermoblade, and the yield math is exact:

• Each plant has 150 HP and takes 8 slashes to destroy.
• Every slash drops a Ghost Weed Seed.
• The last (9th) slash — the one that destroys the plant — drops an additional seed, for 9 seeds total per plant.

So one plant = 9 seeds if you finish it, not 8. There's no reason to stop early; the 9th seed is free.

Seeds can be planted? No — ghost weed is one of the few harvestables you cannot grow in an Exterior or Interior Growbed (the wiki lists no growable variant), which is why the wild patches matter. If you need more than the Lost River provides, remember the Blood Kelp Trenches have their own large populations.

What Is Ghost Weed Used For?

Two uses, one trivial and one essential:

1. Hatching Enzymes (essential). The Hatching Enzymes are the enzyme mixture that hatches the Sea Emperor's eggs and ultimately cures the Kharaa bacterium. The official wiki's recipe is:

• 1 × Eye Stalk Seed
• 1 × Fungal Sample
• 1 × Ghost Weed Seed
• 1 × Sea Crown Seed
• 1 × Bulb Bush Sample

Crafted at the Fabricator. This is a mandatory story item — you cannot finish Subnautica without it, and you cannot make it without ghost weed seeds. The other four ingredients are all growable or common; ghost weed is the one you must go and find in the deep.

2. Bioreactor fuel (trivial but useful). Each Ghost Weed Seed burns for 70 energy in the Bioreactor — the same value as Creepvine Seed Clusters and most plant seeds, and far better than spores. If you're running a base in the Lost River (a common lategame setup), a locker of ghost weed seeds is free, renewable power without dragging fish home.

FAQ

Where can I find ghost weed in Subnautica?

Mostly in the Lost River (Bone Fields, Corridor, Ghost Forest, Mountains Corridor), with large patches in both Blood Kelp Zones and only a few specimens in the Bulb Zone and Mountains.

How do I harvest ghost weed seeds?

Cut the plant with a Survival Knife or Thermoblade. Each plant takes 8 slashes and drops 9 seeds total — the 9th, bonus seed comes from the final slash that destroys it.

What is ghost weed used for?

Its seeds craft the Hatching Enzymes (the endgame cure component, along with Eye Stalk Seed, Fungal Sample, Sea Crown Seed and Bulb Bush Sample) and burn for 70 energy each in a Bioreactor.

Is ghost weed in the Lost River?

Yes — the Lost River is its main habitat, especially the Ghost Forest and Bone Fields, often around brine pools.

How much energy does a ghost weed seed give a bioreactor?

70 units per seed, matching the best plant-seed tier in the game. Compare that with fish fuel in our Subnautica fish guide — for base power, plants and fish are both strong options depending on what's near your base.

Related Guides

• Subnautica Kyanite Guide — Lava Zones and Endgame Recipes
• Subnautica Multipurpose Room Guide — Blueprint, Building and Power
• Subnautica Fish Guide — Every Edible Fish and What They're For
• Subnautica Prawn Suit Guide — Fragments, Arms and Upgrades
• Valheim Biomes Guide — Every Zone Explained

Last updated: August 13, 2026.