Agriculture, removal of water?

I want to grow wheat in Minecraft. Wheat needs water. Now I want to know how long the water lasts for the seeds to be moistened.

4 blocks from the water source.

https://minecraft-de.gamepedia.com/...Ackerboden

OK thanks

8 blocks are enough

Thank you

How do you get 8?

Every 8 blocks one. So a water source is enough 4 blocks in all 4 directions

That's just how it is

As you can see in the wiki and picture above, it just doesn't.
So please don't spread untruths.

One water goes 4 blocks in all directions.

So you can irrigate a total of 8 blocks between the water sources (4 from each side).