Moss & Bone Meal Farm

Bone meal applied to a moss block has a chance to spread the moss to nearby stone-type blocks, and can also spawn glow berries, azalea saplings, or grass and flowers around it. The real reason this farm exists, though, is the loop that follows: that plant growth, once collected and composted, has a chance to produce more bone meal, which feeds right back into spreading more moss.

In practice you usually want some renewable stone surface, a simple generator loop feeding a flat floor, for the moss to spread onto, since moss consumes the stone it spreads to and needs a fresh supply or it just runs out of surface after a few cycles.

A piston and observer setup handles the actual loop: bone-meal a moss block, wait for the resulting growth, harvest it with a second piston pass, and funnel the drops into composters. Composting plant matter has a chance to fill a composter with fresh bone meal, closing the circle back to the start.

This is one of the more redstone-heavy builds on this page, not because any single part is hard, but because it's really three simpler mechanics chained together: a stone generator, a moss-spread trigger, and a composting loop. That's the honest reason it's rated medium instead of easy, despite involving zero combat.

The payoff is a bone meal supply that doesn't depend on a mob farm at all, useful if you'd rather not build a skeleton spawner farm just to keep a crop farm force-grown, plus a steady trickle of moss and carpets that otherwise only show up naturally in lush caves.