diff --git a/GROUPS.md b/GROUPS.md
index 41b0a0d7a..9a649ddfb 100644
--- a/GROUPS.md
+++ b/GROUPS.md
@@ -34,6 +34,7 @@ Please read <http://minecraft.gamepedia.com/Breaking> to learn how digging times
 * `cultivatable=2`: Block will be turned into Farmland by using a hoe on it
 * `cultivatable=1`: Block will be turned into Dirt by using a hoe on it
 * `flammable`: Block helps spreading fire and gets destroyed by nearby fire (rating doesn't matter)
+* `spreading_dirt_type=1`: A dirt-type block with a cover (e.g. grass) which may spread to neighbor dirt blocks
 * `soil=1`: Saplings and other small plants can grow on it
 * `soil_sapling=2`: Soil for saplings. Intended to be natural soil. All saplings will grow on this
 * `soil_sapling=1`: Artificial soil (such as farmland) for saplings. Some saplings will not grow on this
diff --git a/mods/ITEMS/mcl_core/functions.lua b/mods/ITEMS/mcl_core/functions.lua
index 26d422277..dd34d0910 100644
--- a/mods/ITEMS/mcl_core/functions.lua
+++ b/mods/ITEMS/mcl_core/functions.lua
@@ -379,35 +379,44 @@ function mcl_core.generate_tree(pos, trunk, leaves, typearbre)
 end
 
 ------------------------------
--- Try generate grass dirt ---
+-- Spread grass blocks and mycelium on neighbor dirt
 ------------------------------
--- turn dirt to dirt with grass
 minetest.register_abm({
 	nodenames = {"mcl_core:dirt"},
-	neighbors = {"air"},
+	neighbors = {"air", "mcl_core:dirt_with_grass", "mcl_core:mycelium"},
 	interval = 30,
 	chance = 20,
 	action = function(pos)
-	if pos == nil then
-		return
-	end
-	local can_change = 0
-	for i=1,4 do
-			local p = {x=pos.x, y=pos.y+i, z=pos.z}
-			local n = minetest.get_node(p)
-			-- On verifie si il y a de l'air
-			if (n.name=="air") then
-				can_change = can_change + 1
-			end
-	end
-		if can_change > 3 then
-			local light = minetest.get_node_light(pos)
-			if light or light > 10 then
-				minetest.add_node(pos, {name="mcl_core:dirt_with_grass"})
-			end
-			
+		if pos == nil then
+			return
 		end
-	end,
+		local can_change = false
+		local above = {x=pos.x, y=pos.y+1, z=pos.z}
+		local abovenode = minetest.get_node(above)
+		if (abovenode.name=="air") then
+			can_change = true
+		end
+		if can_change then
+			local light = minetest.get_node_light(above)
+			local p2 = minetest.find_node_near(pos, 1, "group:spreading_dirt_type")
+			if not p2 then
+				return
+			end
+			local n2 = minetest.get_node(p2)
+
+			-- Light level for grass block and others
+			local minlight = 4
+			if n2.name == "mcl_core:mycelium" then
+				-- Light level for mycelium
+				minlight = 9
+			end
+
+			if light >= minlight then
+				-- Spread the grass/mycelium!
+				minetest.set_node(pos, {name=n2.name})
+			end
+		end
+	end
 })
 
 --------------------------
diff --git a/mods/ITEMS/mcl_core/nodes.lua b/mods/ITEMS/mcl_core/nodes.lua
index 6ca8bba35..2c4004430 100644
--- a/mods/ITEMS/mcl_core/nodes.lua
+++ b/mods/ITEMS/mcl_core/nodes.lua
@@ -366,7 +366,7 @@ minetest.register_node("mcl_core:dirt_with_grass", {
 	tiles = {"default_grass.png", "default_dirt.png", "default_grass_side.png"},
 	is_ground_content = true,
 	stack_max = 64,
-	groups = {handy=1,shovely=1, soil=1, soil_sapling=2, soil_sugarcane=1, cultivatable=2, building_block=1},
+	groups = {handy=1,shovely=1, soil=1, soil_sapling=2, soil_sugarcane=1, cultivatable=2, spreading_dirt_type=1, building_block=1},
 	drop = 'mcl_core:dirt',
 	sounds = mcl_sounds.node_sound_dirt_defaults({
 		footstep = {name="default_grass_footstep", gain=0.4},
@@ -422,7 +422,7 @@ minetest.register_node("mcl_core:mycelium", {
 	tiles = {"default_mycelium_top.png", "default_dirt.png", "default_mycelium_side.png"},
 	is_ground_content = true,
 	stack_max = 64,
-	groups = {handy=1,shovely=1, building_block=1},
+	groups = {handy=1,shovely=1, spreading_dirt_type=1, building_block=1},
 	drop = 'mcl_core:dirt',
 	sounds = mcl_sounds.node_sound_dirt_defaults({
 		footstep = {name="default_grass_footstep", gain=0.4},