Grassidium
Grassidium lets grass, ferns, seagrass, kelp and other small plants spread and grow tall on their own, based on the conditions around them.
What it does
Plants that spread in a world are controlled by the blocks nearby and the light level. Grass, ferns and seagrass can multiply into their neighbors, grass and sea pickles grow tall versions, and the spread also works underwater. Solid blocks stop spreading completely, while fences, iron bars and glass only lower the chance of spread. Plants of the same kind packed together stop spreading once they fill the space around them.
Modded plants take part too, since the mod reads the vanilla plant block tags to decide which blocks count. Rain, the speed of growth, the light needed and the chances can all be set in the config file, and the Set World Creation Game Rules and World Updates options control the behavior per world with an in-game gamerule. Because the mod runs on the server, players join without installing anything.
Grassidium is published for NeoForge only, with builds for 1.21.1, 1.21.4, 1.21.10, 1.21.11, 26.2 and 26.3, under All rights reserved, so the code is not open source. The latest file is 1.2.0+26.3 for 26.3, released on 2026-09-22.
Key features
Spreading small plants
Grass, ferns and seagrass spread into nearby blocks, and sea pickles and kelp multiply over time.
Growth rules
Plants grow faster in good light, and rain and the type of land change how far they spread.
Crowding and solid blocks
Dense clusters of the same plant stop spreading, and solid blocks stop spreading into them completely.
Modded plant support
Modded plants work automatically, because the mod uses the vanilla plant block tags.
Per-world gamerule
A gamerule set during world creation or in-game controls the behavior in each world.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Questions
Does Grassidium need to be installed on the client?
Which versions does Grassidium support?
Can the spread be changed without editing the config file?
In the catalog
Grassidium is one of 8,515 World generation mods on ModsFinder, and one of 4,175 World generation mods for NeoForge. 8,071 mods support Minecraft 26.3.
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What the author says
Plants spread to nearby blocks depending on light, and by default they do it faster in the rain (land plants only). Small plants like grass, ferns and seagrass can grow into their tall versions, and sea pickles multiply in place. It works underwater too: seagrass, kelp and corals spread on their own. If too many…
Official listing
- Modrinth page
- modrinth.com/mod/grassidium
- Owner
- DimaYastrebov
- Published
- 2026-03-03
- Updated on Modrinth
- 2026-09-22
- Facts verified
- 2026-10-15