Sandy's Fertilizer is green in color and is kept in a spray bottle with an image of an acorn on it.
Sandy creates this formula after seeing her tree is dying and is not producing enough acorns needed for winter. However, the formula works too well, and it produces more acorns than Sandy can handle. Sandy then gets the idea to use all of the acorns to make Nutty Butter. The Nutty Butter is a huge hit, and Sandy ends up giving away a bunch of it, forcing her to use her fertilizer once more to produce more acorns. Unfortunately, overusing the fertilizer causes her tree more harm than good, and Sandy is forced to stop using the fertilizer altogether.