Why did early farmers often have more belongings than hunter gatherers?

The answer itself can be seen in the question.

"Because the farmers were sedentary; they didn't move around."

The nomads (hunter/gatherers) had difficulty remaining in one place. As seasons changed the food dwindled and animals moved to new areas, and the nomads could either follow or starve. Thus they had to remain mobile, and as such they acquired few items.

Farmers on the other hand, sat in one place, so storage of items or collection of resources and tools was not only possible, but almost mandatory.