Your Own Urine As Fertilizer For Cannabis
This isn’t an urban legend, your urine is a fantastic fertilizer for your marijuana plants.[1] Its been this way in nature since animals first started to piss.
As bizarre as it sounds, fresh human urine is not only high in nitrogen, but also improves circulation of other key nutrients in weed growth.
- Never pee on your cannabis plants, it could actually kill them! Urine contains lots of salts we must dilute before applying.
- Only use urine if you are healthy. Don’t use it if you are on medication either.
Pros
- It works as good as commercial fertilizers when used properly.
- Great NPK ratio for vegetative stage.
- Recycles what would otherwise be waste.
- It's free!
Cons
- There are hygienic risks in case the person is not healthy.
- Urine fertilizing is not an exact science, and can't be the same for every grower.
- Salts are abundant in human urine.
Components Of Urine
Urine is a blood byproduct that is primarily composed of 95% water, and 5% urea, and a mixture of minerals, salts, hormones, and enzymes.[2] Although it contains some waste products, urine is non-toxic and can serve as an effective fertilizer for cannabis plants.
Nitrogen is one of the primary macronutrients that plants need for healthy growth, and a deficiency in nitrogen can lead to stunted growth, yellowing leaves, and reduced yields. If you're experiencing nitrogen deficiency in your cannabis plants, read my guide on Nitrogen Deficiency.
Luckily, urine is a rich source of nitrogen, with a typical N-P-K ratio of 11-2-4 for individuals following a Western diet.
| mmol L−1 | mg L−1 | |
|---|---|---|
| SO42− | 12.74 | 1223 |
| Na+ | 57.66 | 1326 |
| K+ | 27.73 | 1081 |
| TANb | 359.8 | 5037 |
| Cl− | 73.15 | 2590 |
| TPc | 11.1 | 344 |
| Conductivity (μS cm−1) | 45.24 | |
| Citrate | nm | — |
| Creatinine | nm | — |
| Glycine | nm | — |
| Hippurate | nm | — |
| l-Cysteine | nm | — |
| Taurine | nm | — |
a Concentrations are measured except endogenous metabolites, which were calculated in synthetic urine based on recipe and not measured (nm) in real urine. b TAN = total ammonia nitrogen = NH3 (g) + NH4+ (aq) (mg L−1 N). c TP = total phosphate = H2PO4− + HPO42− (mg L−1 P).
Source: Pubs.rsc.org
What Do Plants Eat?
For a comprehensive overview of essential nutrients for growing cannabis plants, check out this great guide to Essential Nutrients for growing cannabis.
Cannabis plants require macronutrients and micronutrients to grow healthy and strong. The macronutrients, including Nitrogen (N), Phosphorus (P), and Potassium (K), play a crucial role in plant growth, resistance, and overall health.
There's also the micronutrients. These are metals and minerals that plants need in smaller quantities. But smaller doesn't mean less important.
Nutrients like calcium, magnesium, copper, iron, zinc, manganese, molybdenum, are essential for cannabis plants.
Commercial fertilizers are the best choice for cannabis to produce their best yield. But there are a lot of reasons for creating or supplementing with your own, homemade fertilizer.
What's The PH Range For Urine?
The pH is the measurement of how acidic or alkaline a person’s urine is. Urine can range from 5.0 to 6.0 on most people[3]. Which is actually great for cannabis.
You also have to know that high protein diets can lower pH (more acidic). And vegetarian diets raise pH values (more alkaline). Things like urinary infections will increase pH value.
Test your pH and the pH of your diluted solution before adding anything to your plants. Make sure it's on the good ranges, especially if in a hydro systems.
How To Use Urine As Fertilizer?
The main thing you should know is that urine must be mixed with carbon-rich materials for bacteria to work it's magic.[4]
The nitrogen in urine is in the form of urea, creatine, and ammonia. The aerobic bacteria convert it into nitrates so nitrogen will be available to your plant.
In soil there's no problems, but in hydro setups there may not be enough bacteria culture to breakdown the urea and ammonia.
Using In Soil
For soil and containers with good drainage.
First, remember that irrigation water should always be left to stand on an open container. For at least 24 hours, to clean it of chlorine and other elements.
The safest ratio is 1 part of urine per 10 parts of water (1:10).
How To Make Watered Down Urine?
- Add pee in a plastic container.
- Now add 10 times more water. For example, if you put 1 liter of urine, you dilute in 10 liters of water. If 100 millilitres then 1 liter.
- Now remove a small layer of soil. Taking care not to damage the roots.
- Add the diluted urine as you would normally add water.
- Refill the layer of soil.
- Water once again with plain water. Just enough to get run off.
And that's it. Although there's few more things that you should know:
- Removing the soil allows you to avoid bad odors and make better use of nitrogen, by achieving less ammonia generation.
- The run off helps to prevent mineral build up in the roots.
- For younger plants start with a ratio of 1:20 or 1:30 and work your way up.
- Don't fertilize seedlings.
Using In Hydroponics
I wouldn't recommend it for hydro. It will be less effective, and worse, it's going to smell.
But if you really want you, this user form the forum Rollitup explains how it's done:
"About 8 ounces (1cup) for every 3 gall or reservoir water has been effective. But make sure to adjust according to your conditions and plant needs."
"So it will be a good idea to drip your res water through a porous material that can support a bacteria culture such as lava rocks, ceramic bio filter material, foam, sponge. It is up to you; it does not need to be fancy just able to support beneficial bacteria." [5]
How Often To Fertilize With Urine?
Once or twice a week, depending on how much you water your plants, should be enough.
Try reading your plants, check their colors, and even check how they stand. Is she big and proud? Or is she shy and droopy? If she looks great, then lay off a little.
Is It Safe For Our Health?
In healthy populations, human urine is almost always sterile. In the rare cases when it isn’t sterile, urine is generally still fine for personal use, or can be stored for several months to minimize pathogen risk.[6]
Most considerable health issues:
- Avoid fecal contamination: this is the most important element in the safe use of urine, as feces have dangerous pathogens.
Special toilets are available that will separate your urine and divert it into a holding tank. Although a simple plastic jug works just fine. - Storing for later: If you are doing it often, it's better you start storing it. When storing the urine for 6 months in a sealed container, you get rid of most pathogens.
