sprout is a patch-only primitive that allows us to ask patches to create new turtles. It must be used within an ask patches [...] context. For example, if we wanted to create a model in which each patch sprouted a flower once it was watered enough, we would write the following code:

ask patches [
    if water-level > 10 [
        sprout 1 [
            set shape "flower"
            set color yellow
            set size 0.1
        ]
    ]
]

Things to keep in mind when using sprout:

• A patch can sprout as many turtles as provided.
• sprout will result in an identical outcome to create-turtles, but it will automatically assign the new turtles' coordinates to the center of the sprouting patch.
• As in create-turtles, you can pass optional rules for the new turtles to follow by simply adding the brackets ([ ]) at the end of a sprout statement as shown above.
• sprout can also be used with breeds. For example, if we had a plants breed, we could use sprout-plants 3.
• Unless specified in the commands, the new turtles will have random headings and colors.
• Only patches can sprout new turtles. If you need your turtles to create new turtles, you should use hatch.

In the model example below, we have an empty garden and a farmer. Our farmer moves around randomly and fertilizes each patch. When a patch is fertilized, its pcolor turns into a lighter brown. Once a patch reaches a certain level of fertilization, it sprouts a new plant. If the farmer fertilizes a patch that already has a plant there, the fertilizer helps the plant grow.