Saluton
Let me start by saying I am brand new to esperanto...less than two months actually...but I am reallt enjoying learning the language. So I amuse myself by looking up various esperanto words. Recently I was searchinf for "barn" and found "grenejo" and "garbejo" so my question is which it? Or what does each translate to in English?

Grenejo estas loko kie oni tenas grenon.
Garbejo estas loko kie oni tenas garbon.
Grenejo is the place they put greno.
Garbejo is the place they put garbo.
Greno is the plant or its eaten part, they make faruno on muelejo(mill)
Garbo is fasko of the plants, they need draŝi(to thresh) to get greno

If I may interpret Sergejm's answer and elaborate it, a barn can be used for different purposes.

to store crops

• Grenejo is the place to put greno.
  
• Garbejo is the place to put garbo.
  
• Fojnejo is the place to put fojno.

to store agricultural machinery

• Veturilejo is the place to store vehicles. (← veturi + ilo + ejo)
  
• Garaĝo is the place to store or repait vehicles, (← garage)

a storing location

• stok(ej)o, magazeno, provizejo, varejo

For a more exact description of the differences between those look up in dictionaries.

Note, that you may perceive a clear difference, say, for you a barn is only for storing crops and never for agricultural machinery, but that may not hold everywhere. So I recommend to take a word and add an explanation to make it clear what you mean by that, for instance

• En la bieno de miaj geavoj estis grenejo por stoki grenoj, sed nenia veturilejo.

Thank you all for answering. I love how esperanto makes me think more about how I use my language. I use "barn" as does my family and locals around my like a catch all agricultural storage building. In local parlance if you were speaking of grain storage youbwould use the term "silo" for eqjipment it would be "shed"
So to continue questioning so could a barn for livestock be "bestejo"?

This is quite an interesting topic.

Let me see, which words I would you if I had to give a tour in Esperanto to the place I spent part of my childhood.

There were three main buildings, the house, the stable and the barn.

The house would be the "domo". Originally half of the ground floor was the pigsty [1] but had been converted into a garage and the heater room. However, it was still referred to as the pigsty because old habits die hard, and in Esperanto I would say either "porkejo" or "porkstalo".

The stable would be the "stalo". It actually didn't contain any animals, but cars, a work shop and storage (for instance the broken oil pump of a 1963 VW, you never know if you might still need it, you never know! Never throw anything away). However as it once was for cattle, we still called it the stable and I would call it the "stalo". Between house and stable there was the dung heap and the cesspit, which I would call the "sterkejo" and the "sterkfosaĵo".

The barn was a three storey building (but only one ceiling between ground and first floor). On the ground floor there was the tractor and a trailer (which for some reasons was called the "rubber cart", maybe because it was the first trailer with rubber wheels my grandfather had), as well as some machinery (wood splitter, saws, wood chipper, etc) and on the first/second floor hay and straw. This building I would call the "fojnejo".

Now to the lean-tos (apparently buildings evolve and have a tendency to bud lean-ons over time). The chicken coop was a lean-to to the stable and I would call it "kokejo". We stored fire wood in a lean-to to the barn, which I would call the "lignejo". Then there was another smaller lean-to to the stable where we stored chipped wood, which I might call the "lignetejo" or "lignerejo".

Maybe 2 kilometres away, we had a "hall" for heavy machinery: loader, backhoe, etc. I would call this the "maŝinejo". Next to it there were two tower silos and two drench silos (all for (fermented) silage and not grain), which I would call "siloj", maybe "altsiloj" kaj "ebensiloj".

So to continue questioning so could a barn for livestock be "bestejo"?

It very well could and I personally would understand it immediately. You can also specify further (for species: ) porkejo, bovejo, kokejo... or (for function: ) melkejo, bredejo... There is also the word "stalo" for stable.

- - - -
[1] Which is quite normal in this region. The idea was that the heat from the pigs heated at least a bit the rooms on the first floor.

Wow thank yall for so much information. Its wonderful to see how different people ise esperanto. I think the use and formation of words in esperanto tells a lot about those who use it and where they are from. It really is great.
For me. I just recently built a barn onbthe fround floor is housing for goats sheep and chickens as needed. As well it serves as place to shear the sheep and may include a milking parlor for the goats the loft is for hay storage. So you see it is a multi functional barn so finding one word to describe it is hard. Any of the words will work and will at least impart some of what it is to those that speak esperanto. Thank you all for helping me understand the differences

Creating a word in Esperanto for Barn on the basis of what is stored in it, is perhaps not the route to follow.

Though maybe 'grenejo' has established itself as an equivalent, through usage, just as lernejo (through usage) is (without qualification) a school and not any place where learning goes on.

Barn:
a large farm building used for storing grain, hay, or straw or for housing livestock.

If 'grenejo' or garbejo seem too specific, why not farm-ŝedo or ŝedego

However a number of languages do seem to have a word for barn derived from the idea of grain - French Grange; Spanish Granero; English Barn from Barley - and if you had asked me for an Esperanto translation of Barn, I have to confess that I would have said grenejo without thinking.

Close that door! Were you born in a barn? Fermu la pordon! Ĉu vi naskiĝis en ŝedego?

Laŭ PIV ŝedo ordinare estas sen flankmuroj. Angle ŝedo verŝajne [legu: laŭ Guglo ] estas shelter, cote, lean-to. Kiel mi komprenas la anglan vorton barn, tiu ja havas murojn.

Metsis, mi dubas ke senflankmureco estas difina aspekto de ŝedo.

Ĉar ŝedo estas verŝajne prunto de la angla lingvo kaj ne estas similforma vorto en aliaj lingvoj eble denaska anglalingvano rajtas pontifi pri kio estas ŝedo kaj kio ne.

Sheds in English can be small like a garden shed, or large such as a railway shed.where whole locomotives may be parked.

However in Esperanto we can distinguish between a ŝedo (kaban-granda) and ŝedego which might be barn-size.

Size does seem to be a defining feature of a barn.

It wouldn't always be necessary to add the augmentative suffix, for example, anybody is going to understand that a fervoja ŝedo (trajn-ŝedo)will be large and a bicikla ŝedo at a school might provide shelter for many bicycles.

On the other hand a ĝardenila ŝedo would be assumed to be small.

If you don't like farm-ŝedo perhaps agrikultura ŝedo will do nicely for a barn.

Sudanglo, you are right. I looked at Wikipedia, and it looks to me that ŝedo is more a warehouse (varejo) than a shelter. So it is seems that PIV has error when it claims "ordinare estas sen flankmuroj". Of course it can be, but "ordinare" is a too strong word here. Besides size I would say what puts a barn apart from a shed, is that you do store fodder or grain in a barn but not in a shed.