One man's junk is another plant's treasure

Dirty Aquarium Water:
Contains: Nitrate & Nitrite which breaks down into Nitrogen
Base pH: Depends on your Aquarium
Best For: All Plants during the Vegetative Stage

Alot of people get mixed up about this one and is why they usually give up in the beginning. While dirty Aquarium water does contain traces of Nitrogen, it is dissolved (or eaten) by other beneficial bacteria in your tank. This bacteria begins after a proper tank cycling otherwise your fish would die of NO2/3 poisoning. By watering your plants with this dirty water, you are building up the levels of Nitrate(NO2) and Nitrite(NO3) in your soil which will begin to slowly break it down into Nitrogen over time. Once this happens the results will be instantly rewarding, and your plants can even be used to directly filter the dirty water in your Aquarium. Read About Aquaponics


Used Coffee Grounds:

Contains: Nitrogen, Magnesium, and small traces of Potassium

Base pH: Acidic (low)

Best For: Tomatoes, Blueberries, Peppers, Potatoes, and all acidic plants

Gently sprinkle dried up used coffee grounds around the base of the topsoil, or pre-mix into soil before transplanting or sowing. Since coffee grounds have a low (acidic) pH, be careful not too add too much otherwise it will drop your soil's pH level as well. Use 2 cups or less of used coffee grounds per every gallon of soil to avoid low pH issues. 

Discarded Egg Shells:

Contains: Calcium and small traces of Nitrogen

Base pH: Neutral

Best For: All Plants, especially during seedling/vegetative stage

*Warning - Fermented eggshells smell rotten and can quickly stink up the house

For seedlings, crush and place broken shells into any water container (which has a lid), and allow the eggs to ferment in water for 48-72 hours. Water your seedlings around the base (but not directly on the leaves) for a quick calcium boost. After transplanting, gently sprinkle dried crushed shells around the base of the soil so that they will get wet during waterings. This will release a consistent source of calcium over time along with your water/eggshell boost.



Fireplace or Wood Ash:
Contains: Potassium and traces of Calcium Carbonate
Base pH: Alkaline (high)
Best For: Plants which require high amounts of Potassium and can tolerate a higher pH.

Wood ash is a natural source for Potassium, however stay away from self-igniting firewood (such as Duraflame etc.) because they contain chemicals which can hurt your plant. Furthermore, wood ash is high in pH value so be careful not too add too much to your soil mixture or topsoil base. Use roughly 1 cup or less per every gallon of soil. Start off small and gradually work your way up to prevent shock, and if you see your plant's health start to diminish then reduce the amount fed.


So can I use all of these 4 ingredients together? 
Yes, and in fact they actually work better this way. If you're growing organically, then you've probably already figured out that you need a mixture of multiple types of organic fertilizer in order to provide sufficient and lasting nutrients. No single organic fertilizer is going to be enough for your garden, unless you buy a pre-mixed bag which was engineered and proven to provide the right amount of nutrients. Call me cheap, but If I don't have to buy fertilizer, and can get if for free out of my trashbag, then I would rather dig through the trash. Here's what I do with these 4 items on this page:
1. Premix my soil & perlite like I would usually do with any plants
2. Sprinkle into the soil mix 2-4 cups of dried used coffee grounds
3. Sprinkle into the soil mix 1-2 cups of crushed egg shells
4. Sprinkle into the soil mix 1-2 cups of wood ash
5. Water heavily, test pH, and allow to completely dry before using

The reason why I water my soil and let it dry is because it will begin the breakdown process of the egg shells, coffee grounds, and wood ash before I use the mix for transplanting/sowing. In addition, the water I use to wet my soil is dirty aquarium water. Furthermore, always make sure to test your pH levels as well, and you can use more wood ash to raise pH, or more coffee grounds to bring it back down.