As you progress towards the Blue crystal you'll come to a section of the map encompassed by a white picket fence, in the center is a shop and a farmer standing next to some Pumpkins. He will tell you he has created a new invention that requires a red seed and water and that both can be found behind the store.. First, you will need to buy the upgrades in the store, mainly the one for fame so you finally have fame stars just above the coins icon. To the left of the store (if staring at the store from the open gate) There is a sign that has a star and 25 under it, you'll need 25 fame to open the tunnel. Down in this tunnel is a water barrel tank much like the one in the starter map.
Behind the store, are a few sponges and barrels that if you smack will pop open and you can look inside and grab a red seed. Bring the seed down to the water barrel and drop it in, go back up and get a sponge, drop it over the edge down to the pumpkin patch and then look to your left/behind and you should see a blue pipe with a wheel you can spin. This will water the pumpkins and your sponge. Jump over the edge, grab the wet sponge and take it down to the tunnel/cave and drop it in the water barrel. At the base of the water barrel is a button that will fill the bucket at your feet with red water.. Drink the water "X".
The achievement will unlock and also grant you the health upgrade.