You use the water from the gaiser to fill up the bucket. :-)
Take the bucket outside and fill it at the geyser. (You will need to break the library door chains with the crowbar.)
go outside and fill it with water from the geyser at the front of the castle, then go back to the plant and now your plant will have water. Filling it with rain does not work.
If you are looking for water to fill up the plant, you go outside to the courtyard, front entrance to the castle and fill the bucket up with water from the geyser. That is the easiest way. Hope it helped.
The water on vampires curse island is used later to grow the beanstalk in the armory atic.
Take the bucket outside and fill it with water from the geyser fountain, then bring it back and use it to water the small plant in the room above the armory. (You can open the doors at the right side of the Great Hall by using the crowbar.)
by using poising,water, paint
I don't know why it wasn't working for you, but if you try this it might help: You need to go to the front entrance of the castle, then when you see the water geyser, right in front, click on your backpack, then on the bucket then click 'USE'. Then bucket should fill up. Hope it helped.
The bucket is in the armory attic next to a large plant. You need it to water the little plant higher up near the boarded window. Take the water bucket to the geyser outside (you can break the door open on the right side of the library using the crowbar). Back in the armory, climb the plant and use the crossbow. Shoot some arrows into the wall at the left, then climb up on them to the top. Use the crowbar on the window boards, then water the little plant. It is apparently a beanstalk.
It is the tower above the armory. Once you fire tha cannon into the ceiling, you can climb up. Use the bow and arrow to shoot arrows into the left side that you can climb up. Use the crowbar to pry open the window. Get the water bucket, fill it up outside, and water the small vine in the attic.
the water spray outside the castle
Use the glass tiger eye (in the tiger head) to get the key to the armory. Inside, pick up the bow and arrow, and fire the cannon three times (load cannonball, get lit candle from fireplace to fire). This will open the ceiling. Then you need to use the bow to shoot arrows into the left wall that you can climb up on, to reach the bucket. Fill the bucket outside (the crowbar will open the chains at the far right) and water the plant.
first in the armory room after u did the cannon thing theres a bucket up there u get that and then go outside using the crowbar and get the water