Bug Spray is an item essential for making plants in the player's Zen Garden happy. It works similar to the phonograph, except each Bug Spray can only be used once. When the player runs out of Bug Spray, they must buy more at Crazy Dave's Twiddydinkies, or else the plants will not provide any money. The reward for spraying a plant is one gold coin, unless the plant is a mushroom or aquatic plant, in which they will give the player three gold coins. Also, if it is a Marigold, it will produce money for a day. The player can buy this item in sets of five at Crazy Dave's Twiddydinkies for $1,000, but can only carry 20 Bug Sprays at a time. The player should use them only when the plants ask for them, as otherwise it will not have any effect and will be wasted. Usually, plants will not ask for Bug Spray until after at least their third watering, so the player won't be using it as much as the Fertilizer.
Although the Bug Spray is useful for making plants happy, if the player just uses it on the plants and does not wait for them to produce money, they will lose money, as it costs $200 each for a $50 ($150 for mushrooms and aquatic plants) net gain, so the player is losing up to $150 per spray. This means that if the player does not have sufficient Bug Sprays for all their plants, they should use them on their mushrooms and aquatic plants before using them on the ordinary plants to prevent losing money. This method may cost a lot of money, but it also brings benefits, as without using the Bug Spray, the plants will continue asking for it and not provide any more money until it is used.
In the Aquarium Garden, the Bug Spray can be used even though it is a liquid. Sprays would just dilute in water in real life.