[SuperCreeper007]

Mycelium spreads to dirt/grass blocks next to it. Because of that, can't you place one block of mycelium, and then let it keep on spreading until you have a whole realm, or maybe even more, full of mycelium?

[Prodigy9]

It won't grow over grass but it will grow over dirt. So if you want a realm full of mycelium, dig up all the grass and replace it as dirt around mycelium.

[SuperCreeper007]

It won't grow over grass but it will grow over dirt. So if you want a realm full of mycelium, dig up all the grass and replace it as dirt around mycelium.

Won't the dirt turn into grass? And am I correct in saying one mycelium can spread to infinity, practically?

[mitchie151]

Yes, Mycelium spreads infinitely to adjacent 'dirt' blocks only. If the block is covered in grass, mycelium will not spread to it.

[Prodigy9]

It won't grow over grass but it will grow over dirt. So if you want a realm full of mycelium, dig up all the grass and replace it as dirt around mycelium.

Won't the dirt turn into grass? And am I correct in saying one mycelium can spread to infinity, practically?

Yes and yes. If you dig out all the grass that you want to turn into mycelium, then replace it all with dirt, some of the dirt may become covered in mycelium and some may become covered in grass. Then, you'll have to dig up the (small, compared to original) amount of grass that grew, replace it with dirt, and wait for it to be covered by a mix of grass and mycelium. Rinse and repeat until you get the mycelium everywhere you want it.

If you want mycelium to spread infinitely (if, say, you want to get it from one realm to another far away realm), you could make a line of dirt blocks either underground or in the air (so it's far away from grass) and place the end of the dirt next to mycelium. Of course, if you're trying to transport it over long distances like that, you're probably better off looking for a silk touch pick to get mycelium blocks that can be placed elsewhere.

[Surgeonbsg]

Just went through this with a realm about a week ago. Here's a couple things to keep in mind. Grass spreads fast. Mycelium not so fast. If you dig up all your grass and replace it with dirt if any grass is left on the sides or underneath the dirt the grass will spread to your newly placed dirt blocks before the Mycelium really has a chance to spread. I recommend digging out your area and then insulating it with cobble. Then place your dirt with your single Mycelium. It worked well for me.

[Prodigy9]

^Solid advise from surgeon. If you go with that strategy, make sure grass doesn't form below a spot that you just dug up (e.g. if the dirt is more than one layer thick).

[mitchie151]

Also: If grass is not exposed to light, it will not grow. However, mycelium will.

[Dugs30]

wow, you guys are all failing at this simple solution XD. All you have to do is dig up the dirt you want to be converted, and then put it one block above... well... anything (I mean so it is floating). Because there is no grass around it then it can't spread. Then, place your block of mycelium and watch it grow.

2nd way: Dig two spaces underground then clear out a whole area. Because mycelium does not currently require light to grow, it will spread and you won't have to worry about grass... Hope this helped!!!

[BSGSamuel]

Grass can also spread two blocks up or down.