There are two ways to use Lureplants to farm things:
- Grow lots of Leafy Meat
- Use the Eyeplants to either kill or harvest something else.
In either case, you will need to transplant Lureplants. This is pretty simple: when you kill a Lureplant using your favorite weapons or allies, it will always drop a Meaty Bulb, which you can pick up like any regular item. Much like a Pine Cone (or, for that matter, Spider Eggs), you can right-click with the Meaty Bulb to plant it somewhere. Lureplants are always harmless; it's the Eyeplants that attack. Eyeplants only have 30 health, so a single (unmodified) Spear attack will take one out. Hacking your way to a Lureplant is easy.
Growing Leafy Meat
There is one special thing about Eyeplants: they don't grow on manufactured terrain like Wooden Flooring, Cobblestones, and the like. So make a bunch of flooring, build it in an area, and then plant a bunch of Lureplants on top of the flooring. Each Lureplant will generate a Leafy Meat every two days, but won't grow anything during the winter.
A cooked Leafy Meat gives you 18.75 hunger, and you consume 75 hunger per day; that's 4 cooked Leafy Meats. In theory, you'll be entirely satisfied by having 8 Lureplants in your farm, assuming that you harvest at exactly the right nanosecond.
You're usually better off using a Crock Pot, but Leafy Meat can't be cooked there; the other uses for Leafy Meat are to give it to the Pig King for gold, to give it to Pigs for labor, or to feed to a bird cage for eggs (whose food value is lower, but which can be used in a Crock Pot).
Harvesting Other Things
Lureplants are entirely harmless, but Eyeplants attack things around themselves. So give the Eyeplants a target! Put it near some Spiders, or plant a twig farm around them. Anything that the Eyeplants kill or pick up will end up in the Lureplant's inventory. If you want to make things easy on yourself, build a path to the Lureplant so that you don't have to kill Eyeplants to get to your loot.
Occasionally, you'll harvest the Lureplant by killing it; this will make it drop everything it hasn't digested yet. (It digests an item every 20 seconds.) Then re-plant the Lureplant, and it will grow Eyeplants again 2 days later and start attacking things again.