The Cave and the Myco-Composter: SFL's new mushroom (and Mud) farming
After the pigs, Chapter 16 uncovers the missing piece: the Cave. Inside are Myco-Composter machines that compost a buried patch for 12 hours, and out of it come mushrooms, beetles, artefacts and —most importantly— the Mud the Pigpen needs to upgrade. It sits behind a testnet feature flag, but the code already carries the full recipes. Here is all of it.
What the Myco-Composter is
The Cave is a new room you enter from a world-map node. Inside, each Myco-Composter sits on top of its own 5×5 patch — 25 buried tiles. It is not like the desert dig: here you choose what to grow (a recipe), wait for it to grow, and only then dig the patch out.
The four figures that define the mechanic: each Myco-Composter hides a 25-tile patch, each batch takes 12 hours, there are 3 recipes to choose from, and one of those tiles is always an artefact.
How to build the Cave
The Cave is not handed to you: you have to build it. Its entrance takes over a world-map island that today is an unused locked chest. The first time you tap it, the build window opens; once built, tapping it takes you straight inside. To build it you need to be on the Spring (Petal Paradise) island or later.
| Requirement | Amount |
|---|---|
 Coins | 5,000 |
 Wood | 100 |
 Stone | 50 |
| Minimum island | Spring (Petal Paradise) |
Inside is a single room with 8 fixed slots in a 2×4 grid. Each slot is a Myco-Composter over its 5×5 patch, and each Cave tier unlocks one: Tier I brings 1 machine and Tier VIII reaches 8. The room grows with every tier. For now the code only defines Tier I; tiers II to VIII arrive in a later ticket. As with the recipes, the build cost is marked as a placeholder until the Cave balance pass.
A batch, step by step
- You pick one of the 3 recipes on the machine. Each consumes different ingredients and starts the batch.
- A fixed 12-hour timer runs. Note: the usual time boosts (shrines, hourglasses) do not apply here; only a future Cave skill will shorten it.
- When it is ready, you come back with Sand Shovels and dig the patch tile by tile, at 1 shovel per tile. Every dig hands you its reward instantly and, unless it was a beetle, a number clue.
- Do not want to wait? You finish it instantly with Gems or Coins, using the same speed-up flow you already know from the rest of the game.
How many batches you can run a day
Each machine holds one batch at a time and stays busy until you dig all 25 tiles or find every beetle: even when the batch is ready, you cannot start another on top of it. At 12 hours a batch, the ceiling is 2 batches a day per machine, and only if you come back to dig on time; every hour a ready patch sits undug is lost production. The way to grow is more machines: the Cave creates one Myco-Composter per tier, so a higher tier means more batches in parallel and more Mud a day. With the maximum of 8 machines, the theoretical ceiling is 16 batches a day.
Your batches survive ascension
If you ascend your island while a batch is growing, you do not lose it: the game keeps the Cave with its machines and their running batches.
The 3 recipes and what they bury
Each recipe splits the 25 tiles among Mushroom, Beetle, Mud and 1 guaranteed Artefact. Mushrooms never share a tile with a beetle. The point of the Mud Mix is its multiplier: every Mud tile pays double.
| Recipe | The 25 tiles | Mud | Ingredient |
|---|---|---|---|
 Mushroom Mix |
| 1× |
|
| Beetle Mix |
| 1× |
|
| Mud Mix |
| 2× |
|
10 Carrot 
10 Egg The ingredients are placeholders
The ticket itself marks the ingredients as placeholders —one item per recipe— until the Cave balance pass lands. The real costs will change, so read the table as the shape of the mechanic, not as final prices.
How digging works: shovels and clues
Every tile you dig costs 1 Sand Shovel, a fixed amount that no wearable or boost changes. Clearing a whole patch takes 25 shovels. Every tile that is not a beetle shows you a number: how many beetles sit in its 4 neighbours (up, down, left and right, no diagonals). It is Minesweeper-style deduction: a 0 tells you its four neighbours are beetle-free, and crossing several clues lets you corner them. A clue never changes as beetles are dug, because it is read from the original board.
The board comes from a seed the server rolls when the batch starts, so you cannot choose it or grind it. That seed is not part of the public farm data, which is why a tool like ours cannot read where anything is. What you always know is how many tiles of each kind there are, because the recipe sets it.
| Tile | Reward | Shows a clue? |
|---|---|---|
| Mushroom | 1 Wild Mushroom | Yes |
| Mud | 1 Mud (2 with Mud Mix) | Yes |
 Artefact | 1 chapter artefact | Yes |
| Beetle | 1 beetle, of random rarity | No |
The odds of each rarity when a tile is a beetle. The game rolls each beetle's rarity separately.
What are beetles for? The code already sets up Beetle Feeds, one per rarity: beetle-assisted alternatives to the usual animal feeds. The game also has trading them wired up, to be switched on separately.
Dig it all, or restart early?
You can start a new batch as soon as you find every beetle, without emptying the patch. But whatever is still buried is lost: the game shows a confirm window listing it. It is a real decision, because every extra tile costs a shovel. If what is left is Mud from a Mud Mix (2 a tile), it is almost always worth digging on; if little is left and you are short on shovels, restarting early puts the machine back to work.
The Artefact, and the loop it closes with the Pigpen
That Artefact tile is a single guaranteed one: it holds the active chapter's artefact. If no artefact is active at the time, the tile falls back to Mud, so the slot is never wasted. And mind the hook: in the Pigpen article we saw Mud had no producer and blocked upgrades — this is that producer. The Cave is where Mud will come from.
Finish now with Gems or Coins
If you do not want to wait the 12 hours, you pay Gems to collapse the timer to right now. It is the same speed-up flow as elsewhere in the game: the less time left, the less it costs. And not only with Gems: the code also accepts Coins, and the popup offers that option when you have enough. One detail: finishing the batch does not hand you the reward instantly, it just leaves the patch ready to dig.
A heads-up on the map
So you do not miss it, the Cave node on the world map shows a badge with how many patches you have ready to dig. It counts the machines whose batch has already passed its 12 hours and leaves out patches already cleared. Inside the Cave, each patch shows your progress (“Beetles found: 2/4”, “All Beetles found!”, “Patch cleared”) and the room shows how many shovels you have left.
In short
The Cave is your factory of mushrooms, beetles and Mud, on a 12-hour rhythm per batch with the option to rush it with Gems or Coins. It is still on testnet, but the full loop is there: pick a recipe, wait, dig with Sand Shovels by following the clues, and decide when to restart. Once it ships and the costs are tuned, it has everything to become a fixed daily stop on the farm — above all for the Mud that unblocks the Pigpen.
