The Rainbow Fertilizer is a limited, prismatic gear added to Grow a Garden as part of the Fall Market event. Its primary function is to temporarily convert a plant into a rainbow-mutated plant for a fixed duration, thereby triggering a powerful multiplier effect. The visual design of the fertilizer is box-shaped, with a green circle and three upward arrows on its front, and it has a black handle, giving it a gear-like look.

How to Get Rainbow Fertilizer in Grow a Garden

Players obtain Rainbow Fertilizer through the Fall event’s reward system. Specifically, it appears among the Fall Energy rewards. Players need to complete the given tasks to obtain limited-time rewards which are granted once every 12 hours. Talk to the Fall Activities NPC to get started. The Fall Activities can include hatching 1 Fall egg, harvesting Parsleys, using a Watering can, feeding a pet etc. To get Rainbow Fertilizer, you require 500 Fall Energy.

Once obtained, the gear can be applied to plants for a span of two hours. During this period, any fruit harvested benefits from a 50x multiplier. Beyond just boosting raw yield, placing a plant into rainbow status also enhances its odds of producing additional rainbow mutations, which are among the most coveted in the game.

Because the effect is temporary, players often strategize to use Rainbow Fertilizer only on plants with already high base value, maximizing return on such a limited resource. Given that only one growth mutation (silver, gold, or rainbow) can apply at a time, switching into rainbow status replaces any existing mutation.

So, if this seems interesting and you want to get your hands on this limited-time gear item, the Fall Energy tasks are what you need to complete as soon as possible. For more Grow a Garden tips and tricks to have the most valuable plot of land, check out our guides on Gamer Tweak.