There is not much too this one and is pretty much needed to progress the game. In the carrot map where I had you colour the Red pickaxe and Payback, in the house right in front of what is either a full carrot field or a now empty one is a water barrel. There is a farmer around the side of the house that will tell you if you mix Acid and a Yellow seed something is sure to happen, so go on and grab a yellow seed and throw into into the water barrel.
The Sponges are located just behind a pixel brick wall in the same field with the water sprinkler (a red should be standing there staring at it ) you can either break the wall while holding a pickaxe (There are at least 3 in this map so if you already gave one to Steve, that's fine) or if you now have the Sword power that lets you break them you can use that. Take one of the Sponges to the acid and throw it on in, it's best to slowly go down the ramp and drop it but don't throw yourself in it it's pretty much insta-death.. Using your purple rope/pull gun grab the sponge and bring it back up the ramp or however you manage to get it out and take the acid filled sponge to the water barrel and drop it in.. Now head back down and press the button to fill the bucket with green juice and drink away "X".
The Achievement should pop the second you finish your drink "Strong".