Whether it is in light or not is unlikely to make a difference in sweetness. If they do not eventually sweeten up--and they now look ripe--and they do this next year as well, I would follow Drew's recommendation and find mulberry trees whose fruit you do like and graft onto your present tree. It is possible that the tree will sweeten up over 4 years in the ground or so, but it is more likely a bum tree.

what a cool idea. I use those bottles for bead storage; cut around 3 sides right where the bottle gets big, and it becomes a box with a hinged lid. Below is a link to google images of bottle greenhouses; looks like most are round pop bottles with the bottoms cut off, and have been threaded on vertical cords or rods placed close together to make walls. Seems like the square bottles could be placed on their sides like bricks. Here is a link that might be useful: bottle greenhouse images

I would think you could add the cranberry juice in lieu of water and it wouldn't cause any problems. To be on the safe side, you could substitute it for just some of the water. The sugar would be food for the microbes and after everything is digested, it should be fairly close to neutral.

I love fresh cranberries, although I am not crazy about cranberry relish. I like it OK, but it is not my favorite cranberry dish by far. I love them in pies, muffins, cakes, etc. It's too bad that most folks only know cranberries for the one time opening of the can at Thanksgiving. I hope I can make some more things with them this winter for the holidays. Here's one I made for Thanksgiving that was a big hit. I had to laugh Jennifer, because my experience was similar, we ended up going for seconds and licking the bowls! Cranberry-Cherry Crumble, from "Cooking Light" magazine 3 cups fresh or frozen cranberries, thawed (that's one package) 3 cups frozen pitted dark sweet cherries, thawed (I didn't measure, just used a whole bag) 3/4 cup granulated sugar 1/4 cup dried cranberries 1/4 cup dried cherries (I just used 1/2 cup dried cherries, no dried cranberries. You could probably sub some raisins too, to save money) 1 TBLSP all purpose flour 1 1/2 tsp. cornstarch (I used some tapioca I found in the cupboard instead of cornstarch) Cooking spray (I used olive oil to oil the pan) 1/4 cup slivered almonds, chopped 1/4 cup regular oats 1/4 cup whole wheat flour (I used regular) 1/4 cup packed brown sugar 1/4 tsp. salt 1/8 tsp. ground nutmeg 1/8 tsp. ground cinnamon 1/8 tsp. almond extract (I left this out) 2 TBLSP chilled butter, cut into small pieces Preheat oven to 375 degrees. Combine first seven ingredients in a large bowl, tossing gently to coat fruit. Spoon mixture into an 8 inch square baking dish coated with cooking spray. Combine almonds and the next 7 ing. (thru extract) in a med. bowl. Cut in the butter with a pastry blender until mixture resemles coarse meal. Sprinkle oat mixture evenly over the fruit. Bake at 375 for 45 minutes or until filling is bubbly and topping is golden. Serves 8