Ok, Americanvalkyrie, I have horrible Nevada soil... where on earth did you find pond scum? I have chickens and have acquired a few tons of horse manure/hay mix... and I drink WAY TOO MUCH COFFEE. All I need is pond scum. Can you help?
I have a manmade pond in my backyard. We get it cleaned every year, and I asked my friend to save all the muck and slime from the bottom. He's a blue-collar DIYer too, so he gladly scraped all of it into buckets. There had to have been 40 gallons of it! The pond was NASTY this year! I water it down and pour it on my plants, or pour a cup of it in the hole before I transplant seedlings. This year I got ducks, and they're chasing the fish, so next spring I might have less fish poop and more duck poop, which will still be great for the soil after spending winter in the water.
If you can't find pond scum, you can always compost. It's not full of fish poop like mine is, but it will still be high in nutrients. You can also buy expensive "fish emulsion," which is the same thing. Or find someone with a manmade pond and offer to clean it.
Coffee: sprinkle the used grounds on the soil under the plants, or mix it in with the soil before planting. Pour cold leftover coffee on your plants. Nightshades like tomatoes, peppers, eggplants really love it. Cream and sugar: not a problem, unless you're afraid of attracting animals that might chew on the plants. Coffee is high in nitrogen, but not as high as chemical fertlizers, so you can put it on brand new seedlings and it won't burn them. I don't drink coffee, so I go to my neighborhood coffee shop with a 5-gallon bucket and smile all friendly-like. Someone from the Nevada thread works at the one closest to me, so I have the hook-up!
I also use the leftover whey from when I make yogurt and cheese. I know this isn't something that a lot of people do, but if you do... HOLY COW my tomatoes love it. I just go out and pour it directly on the soil beneath the plant. I had a few container tomatoes that I had accidentally waterlogged, and I treated them with yogurt whey, and now they're super green and growing tomatoes. The probiotics are good for the soil, I'm sure.
Nevada gardening: If there is one, I haven't found it. We talk about it a lot on the Nevada thread, though. And gardening in Reno is SOOOO very different from gardening in Vegas.
Horse manure: I use it, mostly because I have a free source with one of my clients, and the dry stuff is great to mix with the bad soil for a good starter garden. Throw in some grass clippings or old chicken straw, egg shells, and go from there. We also have a couple of rabbits, so once a week I go get their manure and throw it around the garden. Unlike chicken poop, it can be used fresh. It's like slow-release pellets.