Space

The one thing the moon does have, thankfully, is water. That means oxygen, water, and hydrogen are provided once you're there as long as you have power. Essentially, the whole point of colonizing the moon can be seen as a source of water outside of the gravity well for engine reaction mass, radiation shielding, and oxygen. Nitrogen and carbon, unfortunately, you gotta ship, though you can get both by recycling it from pee and the air respectively. That's why I mention hydroponics, because getting bioavabile nitrogen from pee is a chemical process.

Granted, I am a nurse. Botany and hydroponics are not my wheelhouse. These regolith experiments people keep doing just seem to be going the wrong way.