The Wild West Granary is used to store things that you grow on your plots which include corn, wheat, rye, beans and more. After a while your granary will fill up to the starting max of 50 spaces. When this happens you wont be able to harvest any more crops until you’ve made room in your Granary. To make room you can plant more crops, make goods that will use your supply, complete orders, help people who visit your farm or upgrade the Granary so you can fit more in it. In order to increase storage space your going to need 3 different building supplies, a Bracket, Rough Plank and Tile.
Granary – Increase Storage
Your going to need 1 or 3 items to raise the max holdings of your Granary. When you do increase it’s level the next time will cost 2 of each items and so on.
Bracket – The Bracket can be found when you dig up things in your garden. Every so often you get an extra bracket in addition to your harvest. These are pretty easy to find as they drop at about the same rate as Tile.
Rough Plank – The Rough Plank is probably going to be the hardest to find. It will pop up while gardening, but the chances are low unless you use higher quality plants. I have found the best luck getting Rough Planks in the newspaper though I had to check often as the ads were on the low side.
Tile – Tile is pretty easy to find, just garden as usual and when you go to dig up your plants you’ll get these every once in awhile.
Newspaper – If your patient and have the coins you can find all the Granary upgrade supplies in the newspaper ads. The price might not always be reasonable so you might have to do some shopping around. The Rough Plank seems to be the hardest one to find out of them all so your gonna have to be extra patient for that one.
For more info check out the Wild West Wiki with guides and tips.