Mulch

Mulch is a type of item introduced in Generation IV. Mulches are basically fertilizers used before planting Berries in loamy soil.

According to the lady in the Berry Master's house in Sinnoh, mulches are made "by mixing high-grade soil with Pokémon...um...you know...".

Mulches promote healthy Berry growth, and there are four types of mulch items:

Sprite	Name	Use	Cost
File:Growth Mulch sprite.png	Growth Mulch	Speeds up the growth of Berries. However, it also dries the soil faster.	$200
File:Damp Mulch.png	Damp Mulch	Slows the growth of Berries and causes the soil to dry slower.	$200
File:Stable Mulch sprite.png	Stable Mulch	Extends the time ripened Berries remain on their plants before falling.	$200
File:Gooey Mulch sprite.png	Gooey Mulch	Ups the number of times new plants grow where mature plants withered.	$200

The Growth Mulch lowers the amount of time for Berry tree maturation to 75% of the normal time, while the Damp Mulch raises it to 125% of the time. For instance, if a Bluk Berry is planted in loamy soil with Damp Mulch, it will bear fruit in 10 hours instead of 8, while if a Sitrus Berry is planted in loamy soil with Growth Mulch, it will also bear fruit after 24 hours, though instead of 32. Using these two mulches, it is therefore possible to cause some Berries with different growth times to grow in the same amount of time.