how many bags of manure

Question

My garden is 8′ by 20.’ How many bags of manure do I use?

Answer 1

8 to 16 cubic feet of compost per 100 square feet of planting bed.

Compost is generally applied at the rate of 1 to 4 inches of depth worked into the top 6 to 8 " of soil depth.

Most bags of compost are 1 cubic feet.

Manure needs to be properly composted before adding to the garden.

https://www.gardeningknowhow.com/composting/manures/the-benefits-of-manure-in-your-garden.htm