Mushroom Shed

Take a piece of lumber (not a branch) and put it on one of the square things inside the mushroom shed. Use mushroom seeds of your choice. Water them. Then continue watering over a period of time.

You put a piece of wood in each one and put the seeds in it

Take lumber and put it on the table then buy seeds from vesta and plant them.

Mushroom House
300 Pieces of... Grass Wood Stone Gold
Supply your own 1000 G 10,000 G 20,000 G 200,000 G
Included w/ cost 7000 G 25,000 G 35,000 G 30,200,000 G

Inside the Mushroom House you'll find 6 wooden pallets. To prepare the pallets for fungus growth, place a piece of wood lumber on it. Now you will have a surface to grow the mushrooms on. There are 2 ways to get mushroom seeds. The first is to buy them from Vesta. She sells Shiitake spores in her shop for 3000 G per bag. Sometimes she can be hard to get in contact with because she's normally outside in her fields, but if you watch her she will move into her shop during the afternoon. The other way is to make your own spores. If you have requested Gotz to build the Maker Barn you then have access to the Seed Maker. During the Fall season you will find two types of wild-growing fungus; Matsutake and Toadstools. You can take the mushrooms, place them in the Seed Maker, and then sow the spores onto the wood lumber inside of your Mushroom House. The regular Shiitake mushrooms do not grow wild, so you would still need to buy those seeds from Vesta. Shrooms take a very long time to grow and you must water them for the fungus to grow big and spongy. When they have begun to mature you can then harvest them. The longer you wait to harvest, the larger the fungus will be. You can pick small, medium, and large mushrooms. Once you've picked the mushroom for the first time, it will regrow back at a faster rate then it took to originally mature. Mushrooms can not produce extra-large specimens like the standard crops do on occasion. Level 01 Growth Small Medium Large
Shiitake 35 days 50 G 80 G 120 G
Toadstool 42 days 100 G 130 G 160 G
Matsutake 59 days 350 G 500 G 800 G

You can also level up your mushrooms just like you can with the standard farm crops. Just sow several bags of spores on the piece of wood in order to upgrade to the next level. Since you are only getting 1 "square" to upgrade you will have to sow several bags to make sure the new mushrooms will be enhanced to the next level. Five or 6 bags will definitely get you to the next level. If you want to remove a stump from your pallets just hit it with your hammer.

Don't worry, I panicked with this for ages!

1: Get some wood and place this wood on each of the tables in the shed.

2: sow the seeds onto the wood which is on the table. (simple right?)

3: water the wood.

4: Keep watering them, and eventually the little mushrooms will grow
and then you will be able to pick them when they are really big.
And they will continue to grow forever so no need to keep on
sowing the seeds and putting new wood on the tables. EASY!

Hope this helped. ;)