Lum

Lum is a type of Berry that can be planted in the Farm. It can be obtained by surrounding an empty plot with all 8 Gen 1 berries in the ripe stage.

Possible Planting Formations
You can fill your farm in the following way to obtain Lum berries. Purple squares indicate where mutations can occur.

Important notes
The total growth time to achieve a field full of ripe Gen 1 berries is short at only ten minutes (without modifiers), but the Lum berry can be challenging to obtain. This is primarily due to the high mutation rates of unwanted berries that can mutate on the center space, as well as the short ripe-death time of Gen 1 berries. It is common to go through many full cycles of this growing process before a single Lum berry has been successfully mutated. As the growth time is so short, if you use the Sprayduck be sure to switch it to a different Oak Item as soon as the Cheri berry is ripe. Furthermore, while getting two cycles of Cheri berry ripeness is possible in one Sitrus cycle, it is often difficult to coordinate this timing with the other berries. When all 8 berries are ripe, be sure to apply a Surprise Mulch to the center plot and Shovel any unwanted berries as they appear. Diligently watching your plots during this process may dramatically reduce the number of Lum attempts necessary to achieve the mutation.

Acquisition

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Using Lum
Farm setups using Lum can be found on these pages:
 * Maximizing Egg step gain for Breeding Pokemon faster
 * Maximizing Shiny Chance to turn all Pokemon Shiny
 * Various useful Farming Setups
 * Jaboca + Lum to increase Roamer encounter chances