To go along with the water bombs, we also have a water slurping frog. He can help us with the bombs, but he also drinks the water drops we need to make our flowers.
The best way to approach this level in my opinion is to make the flowers first. Depending on availability of the seeds and water drops. Sometimes they drop down quickly, other times they don't.
While avoiding the frog on this very small board, and making and opening flowers, you also need to collect a lot of crops. You don't have the board space to allow generosity. So what you need is falling crops to add points.
Apart from the water, you only get crops you need, so make sure you save shovels. If you get a really lucky board you can probably do it with 3 but it will take time to get that board.