You can do it now or in the spring. I do a no-till approach, so I would just spread it and put some straw on top of it and leave it for the winter. In the spring, just plant as normal and forget about the tilling. Just aerate the soil as you would the lawn before you plant. But if you need to till, I would do it now instead of the spring and then not till in the spring.

I've read that compost is beneficial in a time frame from months to a year or two. Considering that compost may not be completely finished, I add it to the soil in the fall as opposed to the following year. And I mulch with compost a few times during the year.

Place your compost now as a mulch cover and it'll start working in right away. No need to till. Cover the entire planting area with a really thick layer of leaves or straw to overwinter and in the spring drag it off before planting. Set your plants or sow your seeds and then mulch with compost if you've got it. Use the straw if you don't. Your soil will become very alive and active and your plants will love you. Oh, fertilize sparingly if you think you need it. Best of luck.

Now is the best time for you to add compost to your soil. It takes some time for the soil bacteria to work on that compost to make what is in it available to your plants so if you waited until spring what you planted after that would not, necessarily, benefit from that compost since the nutrients would not be available for some time. Just be sure you have a good mulch on that garden soil for the winter because that mulch will aid in keeping the soil warmer longer, retain soil moisture, and prevent erosion of your soil.

The best time to add soil ammendments -- and I include rock powders along with compost -- is in the fall. There is quite enough to do in the spring, and you need time for the ammendments to become part of the soil. Certainly you should cover the prepared soil with a mulch or a cover crop. In my opin., the best mulch is shredded leaves, but straw comes a good second. Regards, Peter.

Thanks for the replies. I'll do it this fall.