Beyond These Stars Expanding the Biome: Terraforming, Compost & Tree Guide

When your Peeps first arrive on Kewa, almost everything outside a small patch of green is dead, barren debris. That's why Beyond These Stars expanding the biome is arguably the most important system in the entire game — no breathable atmosphere means no new mines, no farms, and no room for your city to grow. Expanding the biome in Beyond These Stars revolves around three buildings and one big idea: turn debris into grass, grass into forest, and forest into livable land.

This guide walks through the full terraforming loop — the landscaper, the compost heap, and the tree nursery — based on hands-on player experience from the early game, including how to avoid the toxic tile disaster that ends runs.

Why Expanding the Biome Matters on Kewa

Kewa is a living, sentient Space Whale, and the ecosystem on its back is fragile. According to the official game description, if you over-exploit the land, your habitat will literally shrink. The flip side is also true: carefully revitalized soil opens up enormous amounts of building space.

Here's what a healthy biome actually unlocks:

• Breathable territory. Peeps can only work and build where trees produce oxygen. No trees nearby means the zone isn't breathable.
• Resource access. In one community-reported run, copper deposits sat just outside the atmosphere — the fix was spreading water, composting bare tiles, and planting saplings until the breathable zone reached them.
• Pollution absorption. Trees passively soak up pollution from smelters and burner generators, reducing your reliance on expensive cleanup.
• Fertile farmland. Irrigated, composted soil is where your first potato patches and farmhouses go.

In short, expanding the biome in Beyond These Stars is the difference between a cramped settlement huddled around one river and a sprawling city stretching down the whale's spine.

The Landscaper: Your Terraforming Powerhouse

Building a landscaper unlocks terraforming mode, which lets you control tile fertility, atmosphere range, and the flow of rivers. You select the landscaping tool, drag over the tiles you want to change, adjust their elevation up or down, and confirm the job. Workers then excavate or fill the terrain.

The landscaper stockpiles all the debris it digs up in a finite internal storage, and it can reuse that debris to landfill elsewhere. That means smart players treat digging and filling as a balancing act — excavate a river blockage in one spot, then deposit that debris to raise the shoreline somewhere else.

A few critical rules of thumb from player experience:

• You can't dig water tiles, but you can landfill them — useful for reclaiming river edges.
• Landscaping grass destroys it. Only reshape terrain where the soil is already dead, or you'll waste compost rebuilding fertility.
• Don't compost tiles you plan to re-grade later. Every elevation change strips fertility, forcing you to recompost.
• Smooth out steep gradients to eliminate the need for elevators, which saves resources and travel time.

The landscaper is also mobile. Once it finishes dredging one section of river, relocate it (along with the compost heap and tree nursery) to the next dead zone. Community reports confirm that abandoned debris drops as a resource cache that gets delivered eventually, so moving isn't wasteful.

Compost Heaps and Tree Nurseries: The Fertility Engine

Once the landscaper is up, two more buildings complete the loop. Here's how they fit together:

The compost heap recycles wood waste — which is why experienced players stockpile it in storage sheds from day one instead of burning it for power. The same logic applies to soot, since cleaners consume it. Producing 10 compost unlocks the tree nursery in the tech tree, and from there you can start planting saplings on freshly composted grass.

Saplings pull double duty, and understanding this is the heart of expanding the biome in Beyond These Stars:

1. Oxygen generation. Check the oxygen overlay — anywhere without trees isn't breathable. Plant saplings and the colonizable zone grows outward.
2. Passive pollution control. Trees planted around smelters, mines, and burner generators absorb pollution before it accumulates into something worse.

That second point matters more than most newcomers realize, which brings us to the biggest threat on Kewa.

Pollution and Toxic Tiles: What Not to Do

Pollution accumulates as you run smelters, mines, and burner generators. If you ignore it, fertile tiles turn toxic — and the consequences are brutal:

Based on one player's deliberately induced disaster (for demonstration purposes), here's the recovery playbook:

• Pause every polluting building immediately. This throws the brakes on before more tiles convert. Notably, a burner generator only produces power on demand anyway, so pausing it costs you almost nothing.
• Deploy toxic tile scrapers as a last resort. These are temporary job sites that remove toxic sludge, but the Peeps doing the scraping are very likely to get sick. Splitting the work across two scrapers means no single Peep absorbs all the health damage.
• Activate cleaners with a chemical supply. Cleaners handle toxic tiles within their range automatically, provided they have soot or chemicals to work with.

The deeper lesson: active cleaning consumes soot, and soot is a finite resource you only produce by burning things — a dirty loop. Passive cleaning with trees is nearly always the better long-term strategy. Ring your metal smelter and burner generator with forest, and you may never need a scraper at all.

Step-by-Step: Expanding the Biome Without Disasters

Ready to put it all together? This sequence reflects the community-consensus approach to Beyond These Stars expanding the biome efficiently:

Step 7 deserves emphasis. In one documented run, completing a terraforming job let the river flow down the spine of the whale — and dormant, dead trees came back to life on their own, dramatically extending the breathable atmosphere without planting a single new sapling. Water is a multiplier on everything else you do.

Also keep an eye on the whale scale tiles visible on the accessible-tiles overlay. Those mark the edge of the playable area — no amount of terraforming lets you build on Kewa's actual scales. Everything else, however, is fair game to annex.

Common Mistakes and Pro Tips

Even players who understand the loop stumble on the details. Avoid these pitfalls:

• Burning wood waste early. It feels like free fuel, but compost is scarcer. Stockpile it.
• Landscaping fertile grass. You'll strip fertility and have to buy it back with compost. Target debris and dead soil only.
• Composting land you intend to re-grade. Elevation changes wipe out fertility — terraform first, compost second.
• Ignoring warnings until tiles flip toxic. The moment you see pollution warnings, pause the worst offenders and let trees catch up.
• Forgetting local supply for outposts. When you push a copper mine far from town, run a road out (ideally elevator-free) and add a hut, hedge garden, and wildflowers so remote workers stay happy.

One final efficiency note: once you unlock power lines, you can relocate dirty buildings away from housing and drop an electronics plant next to the metal smelter for its pollution-reducing adjacency. Rerouting grids is cheap; a dead Peep is not.

FAQ

How do I expand the breathable atmosphere in Beyond These Stars? The core loop for Beyond These Stars expanding the biome is: dig rivers with the landscaper, compost bare debris tiles into fertile grass, then plant saplings from the tree nursery. Trees generate oxygen, and flowing water irrigates soil so even dormant trees revive and stretch the breathable zone further.

Why did my tiles turn toxic and shut everything down? Pollution accumulated past the threshold and converted fertile tiles into toxic ones. Peeps won't work in toxic zones, and walking through them drains energy — sometimes fatally. Pause all polluting buildings, deploy toxic tile scrapers as a last resort, keep cleaners stocked with soot, and plant forests around polluters to prevent a repeat.

Can I dig out water tiles with the landscaper? No — water tiles can't be excavated, but they can be landfilled using debris stored in the landscaper. Use this to narrow rivers, reclaim shorelines, and create extra building space, then compost the new land if you need fertility there.

Where should I place the compost heap and tree nursery? Both buildings reward adjacency. Community experience puts the compost heap directly beside the landscaper for a production speed boost, and the tree nursery near both the heap and landscaper. The tree nursery's adjacency trade-off in one reported run was faster production at the cost of reduced on-site storage — usually a worthwhile deal.