Potato

While potatoes do give the best calories, if you're going to grow something in you're farm base, make it pumpkins still. For a sacrifice of 20 calories you get 4 more healing over-time. And in the heat of battle, having a stack of pumpkins can be more useful then potatoes.

Potatoes spawn in the dark green areas of the forest biome. Credit to rustmaps.com.

Requires an average of 5 mL per plant per minute and matures in as little as 90-100 minutes under lights.
Produces between 10-12 potatoes per plant under optimum conditions, and as many as 16 with the right genetics.
Optimum water level for planters is between 4000-8000 mL for the large boxes.
Stacks up to 20 per slot.