To change a plants Resource settings go to the plants blueprint so for example the BP_TomatoPlant and select the BP_PlantComponent in the Components panel, then in the Details panel and inside the Plant Settings Category find the Resource category like the image below.
Here you can change this plants Resource settings, you can hover your mouse over each settings name to get a tooltip with more info about each setting.
These resource settings allow you to have plants that produce resources that can be harvested without using the vegetable system, this could be useful for plants that dont grow a vegetable but the plant itself is a resource that you want players to be able to harvest, like for example a bamboo plant.
If Produce Plant Resources is true when the plant is harvested the player collects resource from the plant separate from the vegetables, this can be used for plants that you want to be harvestable but dont want to have those plants grow vegetables.
Death Plant Resources are resource the player would receive if they harvested the plant when its dead.
Plant Resources are resource the player will receive from harvesting the plant, Note – these resource amount are effected by the Yield system if that system is enabled. You can find more info about Yield in the guide below.