I added my compost to my vegetable garden and it was not completely composted. It was very black but with material in it. It seemed to create a mass of weeds. How long or what should compost look like before adding to garden?
It sounds like your compost was not completely "cooked." As the various levels of the compost decompose, heat is produced. This is what kills the weed seeds. Compost is great stuff -- here's some more information on making it. https://www.gardeningknowhow.com/special/organic/compost-for-organic-gardens.htm