Why do coffee grounds make good fertilizer?

Question

what if I'm doing a science fair project and my cup doesn't have any worms.

Should I use coffee grounds as a varible?

or should I just use fish food as a varible? How does fish food make a good fertilizer?

Answer 1

Coffee grounds are a low-level source of nitrogen, having a fertilizer value of around 2.0-0.3-0.2, as well as a minor source of calcium and magnesium. Post-brewed coffee grounds are reported to be slightly to highly acidic, depending on the source, but no more so than peat moss. So, one could apply them to the soil for acid-loving plants, such as rhododendrons, azaleas and blueberries, etc. Or, you could spread them out over a larger garden area to minimize the pH effect. It's difficult to make a specific recommendation for an application rate, but it's always better to err on the lighter side, since the pH can be variable. A rate of 10 pounds (dry weight) per 1000 square feet would be conservative.
TO ANSWER YOUR QUESTION, MORE SPECIFICALLY:
Composting is also an excellent method to recycle the grounds, which have a carbon-to-nitrogen ratio of around 20:1. Use the grounds as you would green, leafy material, mixing with some dry, brown plant materials in the compost. The Environmental Protection Agency suggests adding no more than 25 percent volume coffee grounds. WORM COMPOSTERS report that coffee grounds are an excellent food source for the little critters. Again, be sure to MIX THE GROUNDS with brown materials (like soggy leaves), even in the worm bin.

Answer 2

Different studies have shown wide disparages in the actual NPK content of used coffee grounds. Maybe the difference in the roast? Anyway these different tests have arrived at figures from 2 percent to as much as 33 percent nitrogen. What they all agree on is that coffee grounds are acid and if used in excessive amounts can change the pH of your soil. They are good for retaining moisture, improving tilth and earthworms love them, so use them on your garden, but sparingly. They do however, make an excellent addition to your compost.

Answer 3

Coffee grounds are in the same catagory as Leaves. When added to the soil they rapidly decay, they furnish a quick source of nitrogen and a valuable source for trace minerals which some plants require along with that they decay to organic matter(worms love decayed organic matter) in which gives the soil a softening resilency and ability to hold moisture.

Contrast that to something like sawdust, or wood, which should never be added to soil in the uncomposted state because it deprives the soil of nitrogen and acts a plant growth retarder until it fully decays.

I would say you use something like sawdust as a contrasting variable.

Answer 4

Coffee grounds aren't necessary a fertilizer,but once they sink into the ground,by raking for instance they keep moist attached to them.In times of extreme heat ,you need not to water the garden daily,And it opens the soil better for better oxygenation of plant roots.
I have turned sand into dark soil like this.
I asked friends who sold coffee to keep the old stuff in buckets for me and they all pitched in.My garden looked never ever better.Proof of it in my album in 360
Pink dragon.

Answer 5

Its because coffee grounds are good food for worms and worms do wonders for a garden