What is green compost and brown compost?
This article will help as well:
https://www.gardeningknowhow.com/composting/ingredients/browns-greens-compost.htm
All good compost should consist of balanced layers of both green and brown materials. Green items generally include grass clippings and kitchen scraps, which add nitrogen to the compost. Brown materials add carbon and consist of things like leaves, newspaper, and small woody materials.
I got some bags of leaves from a neighbor and then realized that they had alot of spiney sweet gum balls in with the leaves. . . will they decompose in the garden and/or should I put them in a long term compost bin. . . how long will they take to bread down. . . . I don't want them in my garden if they won't break down.
They will only break down if you have a "hot" compost pile. If your compost pile stays cool, the seeds will not break down and you should not place them in the pile. A hot compost pile is one that is turned and watered regularly and gets to an internal temperature of more that gets above 100F.
Where is the best place to put a compost pile--in sun or under trees? I have wooded land next to me. I wanted to put my pile in there so it was out of sight. Will it get hot enough in shade?
You can get a pile to heat up in the shade. You can do this by making sure it has the right balance of browns, greens, water and air. This article will help:
https://www.gardeningknowhow.com/composting/basics/heating-up-compost-pile.htm
Are (oak tree) acorns okay to compost? I'm concerned about the tannic acid content of the acorns. If acorns are okay, is there a limit or ratio of acorns that is too high? And if compost has a sizable acorn content, is there any usage that this compost would not be advisable for?
You can compost them. As long as you have the "green" material in the compost to balance them (they would be a brown material), you cannot have too many.
I have used compost in my garden for years, but I get frustrated with the sprouting of multiple plant seeds. I end up with unintentional tomatoes, squash, etc.coming up when I use the compost. How do you keep the seeds in the compost from sprouting?
If the seeds in the compost are sprouting, it means that the compost is not "heating" up properly. Every couple of weeks, add a shovelful of dirt to the pile and also make sure that your browns and greens are in balance. This will get the microbes going and the compost pile will heat up to a temp where it will kill the seeds.
Is the compost 'safe' to use on the garden after a rat/mouse has been found in it?
This should not cause any problems. Just be sure to wash anything you eat from the garden, as you normally should anyway.
I have a big plastic, upright composter. It has 2 or 3 inch holes all around it and a square hole on the bottom side (not sure what for). I put all food scraps in it (absolutely no meat). My question is. . . Do I need to add dirt to the food to make it turn into dirt, because after a year it got half full and the food was just dry and probably rotten inside? So now I want to start again. Should I cut the bottom out of this composter, add dirt or what?
Compost is made up of greens and browns. This means that in addition to food scraps, you should also be adding leaf and plant litter (leaves, branches), grassclippings, newspaper, etc. This should be mixed every so often. This article will help: https://www.gardeningknowhow.com/special/organic/compost-for-organic-gardens.htm