Pee on your backyard flowers and vegetables to make them grow 👍💖. There is an interesting little article in The Times today (Monday, September 30, 2024). It’s about human urine acting as a synthetic fertiliser to grow better plants and vegetables in your back garden essentially. Of course, it got me thinking. It got me thinking about cat urine and how gardeners hate it and cat faeces. It got me thinking about all those hundreds of thousands of articles on the Internet about how to keep domestic cats away from your neighbour’s garden. I thought that perhaps cat urine might actually be a fertilizer as well to make all these articles completely redundant. But not quite. It didn’t work out quite like that but it got close as you can see from the subheading sections below.
In this Times article, the journalist Kaya Burgess, tells us about some research at the University of Birmingham in which the conclusion was that “domestic flower beds and vegetable patches can benefit from a weekly dose [of human urine acting as a synthetic fertiliser].
Ideally human urine which is to be used as a fertiliser should be stored in an airtight container for at least six months first according to the researchers because it increases the alkalinity of the urine making the pH level about nine which is enough to kill any potentially harmful bacteria.
The study is published in the journal Applied Soil Ecology. They found that “growing spinach using synthetic fertiliser led to a yield “slightly higher” but not significantly different than that from crops given a weekly diluted mixture of one part urine to ten parts water.”
When urine is stored for six months in an airtight container it should result in a “fertiliser” which can inactivate most bacteria. And the researcher said that it was quite feasible to consider using human urine as a fertiliser in your backyard. That might surprise some people and I suspect very few people consider doing it but there it is. It’s based upon hard research so we can’t argue with it.
Below are some of my questions directed at artificial intelligence which provided the answers and from which you can discover the difference between cat and human urine and why cat urine is not quite suited as a synthetic fertiliser to help grow your vegetables and plants in your backyard. However, it does point to the fact that cat urine is not quite so obnoxious as perhaps some gardeners had thought although the strong ammonia content could scorch plants if there was a persistent exposure to it. On a one-off basis it would appear to be perfectly okay.
Difference between cat and human urine?
Yes, there are several chemical differences between human and cat urine, reflecting variations in physiology, metabolism, and diet between species. The major differences include:
1. Concentration of Compounds:
- Urea and Creatinine: Both human and cat urine contain urea and creatinine, but cats have higher concentrations of urea due to their more protein-rich, carnivorous diet. Their urine also tends to be more concentrated.
- Ammonia: Cat urine contains more ammonia than human urine. This contributes to the stronger, pungent odor in cat urine, particularly when it breaks down over time.
2. pH Level:
- Human Urine: The pH of human urine varies depending on diet but typically falls in the range of 4.6 to 8.0. A balanced human diet usually results in slightly acidic to neutral urine (around pH 6).
- Cat Urine: Cats, as obligate carnivores, tend to have more consistently acidic urine, with a pH around 6 or lower, due to their high-protein diets. Some commercial cat foods may influence pH to avoid urinary tract issues.
3. Sulfur-Containing Compounds:
- Thiols and Felinine: Cat urine contains sulfur-containing compounds like felinine, a precursor to the strong-smelling pheromonal compounds unique to cats. Felinine breaks down into other thiols and sulfurous compounds that give cat urine a characteristic “catty” smell, especially in unneutered males. These compounds are absent in human urine.
4. Specific Pheromones and Markers:
- Cats release pheromones and other species-specific markers through their urine, which are not present in human urine. These are used for communication and territory marking in cats.
5. Water Content:
- Cats, being desert-adapted animals, conserve water more efficiently than humans, leading to more concentrated urine. This lower water content increases the intensity of odor and the concentration of chemicals like urea and ammonia.
6. Bacteria:
- Microbial Composition: The composition of bacteria in urine (especially during infection) can differ due to species-specific flora. Cats may harbor different microorganisms in their urinary tracts compared to humans, contributing to differences in smell and chemical breakdown products.
7. Color and Odor:
- Odor: As noted earlier, cat urine has a much stronger, pungent smell due to higher concentrations of ammonia, urea, and sulfur-containing compounds like felinine. Human urine typically has a milder odor unless affected by dehydration or certain foods (like asparagus).
- Color: Both human and cat urine can range from pale yellow to darker amber, depending on hydration. However, because cats conserve water more effectively, their urine is often darker and more concentrated than human urine.
These differences arise largely due to cats’ unique physiology as obligate carnivores, their efficient water conservation, and their use of urine in communication and territorial marking.
A study found that human urine can act as an artificial fertiliser to growing vegetables. Your thoughts?
Yes, human urine can indeed act as an effective natural fertilizer for growing vegetables. Urine contains essential nutrients that plants need for growth, making it a valuable resource for sustainable agriculture. Here’s a breakdown of how and why human urine can be used as fertilizer:
1. Nutrient Composition of Human Urine:
Human urine contains many of the same key nutrients found in commercial fertilizers, such as:
- Nitrogen (N): A major component that promotes leafy growth in plants. Urine is especially rich in nitrogen, mainly in the form of urea.
- Phosphorus (P): An essential nutrient for root development and flower/fruit production.
- Potassium (K): Important for overall plant health, promoting resilience to stress, drought, and disease.
- Trace Elements: Human urine also contains small amounts of magnesium, calcium, and sulfur, all of which are beneficial for plants.
2. Advantages of Using Human Urine as Fertilizer:
- Sustainability: Human urine is a renewable resource that can be recycled into the agricultural system, reducing the need for synthetic fertilizers.
- Cost-Effective: It provides a free, easily accessible source of nutrients compared to commercial fertilizers.
- Environmental Benefits: The use of urine as fertilizer reduces the need for energy-intensive production of chemical fertilizers. It also helps minimize water pollution caused by nutrient runoff from traditional fertilizers.
- Fast-Acting: Urine is in liquid form, which makes it easy for plants to absorb the nutrients quickly.
3. Studies on Urine as Fertilizer:
Various studies have confirmed the efficacy of human urine in enhancing plant growth:
- A study published in the Journal of Agricultural and Food Chemistry found that human urine, when diluted with water, can be as effective as chemical fertilizers in promoting the growth of vegetables such as tomatoes, cucumbers, and lettuce.
- Another study on sustainable farming showed that crops grown with urine fertilizer had comparable or even superior yields to those grown with synthetic fertilizers.
4. Practical Application:
- Dilution: Since urine is high in nitrogen, it is often diluted with water before being applied to plants. A common recommendation is a dilution ratio of 1:10 (one part urine to ten parts water) to prevent over-fertilization and potential “burning” of plant roots.
- Application Timing: It’s best to apply urine during the plant’s active growth phase (early in the season or during vegetative growth) rather than during flowering or fruiting stages when excessive nitrogen may inhibit fruit production.
- Safety Considerations: Urine should ideally come from healthy individuals with no infections, and proper hygiene practices should be followed to avoid contamination. Pathogens are typically not a concern with urine compared to feces, but dilution and proper handling are still recommended.
5. Crops That Benefit from Urine Fertilization:
- Vegetables like tomatoes, cucumbers, lettuce, spinach, and peppers respond well to urine fertilization.
- Leafy greens, in particular, benefit greatly from the high nitrogen content in urine, as nitrogen promotes lush, green growth.
6. Limitations and Considerations:
- Salinity: Repeated use of undiluted urine over time may increase the salinity of the soil, which can harm plants. Diluting the urine helps prevent this issue.
- Over-Fertilization: Excessive use of urine, especially without dilution, can lead to nutrient imbalances in the soil, negatively affecting plant growth.
- Cultural and Psychological Barriers: While urine is effective as a fertilizer, there can be a “yuck” factor associated with using human waste in food production, which can deter people from adopting this practice.
7. Urine and Composting:
Urine can also be used to accelerate the composting process, providing moisture and nitrogen that help break down organic materials more quickly. Composting with urine creates a balanced fertilizer mix that benefits plants more holistically.
Conclusion:
Using human urine as a fertilizer is an effective and sustainable practice that offers many benefits, especially in small-scale farming or gardening. With proper handling and dilution, it can provide essential nutrients that promote healthy plant growth while reducing reliance on synthetic fertilizers and supporting environmental sustainability.
Can domestic cat urine can act as an effective natural fertilizer for growing vegetables as well?
Domestic cat urine contains some of the same key nutrients as human urine, such as nitrogen, phosphorus, and potassium, but it also presents challenges that make it less ideal for use as a natural fertilizer for growing vegetables. Let’s examine its potential as a fertilizer and the reasons why it may not be as suitable as human urine:
1. Nutrient Composition:
- Nitrogen (N): Like human urine, cat urine is rich in nitrogen, primarily in the form of urea. Nitrogen is essential for plant growth, particularly for promoting green, leafy growth in vegetables.
- Phosphorus (P) and Potassium (K): Cat urine also contains phosphorus and potassium, both important for root development, flower, and fruit production.
- Concentration: However, the concentration of urea and ammonia in cat urine is significantly higher than in human urine, which can make it too “strong” for plants unless properly diluted.
2. Challenges with Using Cat Urine as Fertilizer:
- High Ammonia Content: Cat urine has a much higher ammonia concentration than human urine. Ammonia can be toxic to plants in high concentrations, especially if the urine is applied directly or without dilution. Ammonia can “burn” plant roots and foliage, causing damage or stunted growth.
- Strong Odor: The pungent smell of cat urine, especially as it breaks down into ammonia and other compounds, is much stronger and more unpleasant than human urine. This odor can linger in the soil, making it undesirable for use around vegetable gardens.
- Potential Pathogens: Cats can carry parasites or pathogens in their urine, such as Toxoplasma gondii, which is of particular concern in areas where vegetables are grown. Toxoplasmosis is a risk to humans, especially pregnant women and individuals with weakened immune systems, and can be transmitted through soil contaminated with cat waste.
3. Soil and Plant Health Concerns:
- Soil Salinity: Cat urine can contribute to increased soil salinity over time, particularly if applied frequently or in undiluted form. High salt levels in the soil can harm plants by interfering with water uptake, leading to wilting and poor growth.
- Risk of Contamination: Cats may carry bacteria and pathogens in their urine, which could pose health risks if the urine comes into contact with edible parts of the plants. Additionally, the breakdown of urine components may create an environment conducive to the growth of harmful microorganisms.
4. Environmental Considerations:
- Territory Marking: Cats use urine for marking their territory, and repeated urination in one spot can result in concentrated patches of high nitrogen and ammonia. This can create “hot spots” in the soil, where plant growth is inhibited rather than promoted.
- Odor and Attraction of Other Animals: The strong odor of cat urine could attract other animals to the garden, leading to potential pest problems. It could also repel humans or neighbors due to the unpleasant smell.
5. Comparison to Human Urine:
- Human Urine: When diluted, human urine can act as a balanced and relatively safe fertilizer with lower concentrations of ammonia, making it more plant-friendly. It also doesn’t carry the same pathogen risks as cat urine, especially when sourced from healthy individuals.
- Cat Urine: Because of its higher ammonia content, the risk of pathogens, and the strong odor, cat urine is far less suitable for vegetable gardens. Even with dilution, these issues persist, making it a less practical option compared to human urine or commercial fertilizers.
6. Potential Uses of Cat Urine:
- While cat urine is not ideal for fertilizing vegetable plants, it might be used for non-edible plants or ornamental shrubs, provided it is heavily diluted to reduce the risk of ammonia toxicity. However, the overall risks, especially to soil health and nearby edibles, still make this a less attractive option.
Conclusion:
While domestic cat urine contains nutrients beneficial to plants, its high ammonia concentration, strong odor, and potential health risks (due to pathogens) make it unsuitable for use as a natural fertilizer for growing vegetables. If you’re looking for a natural fertilizer, human urine (when properly diluted) or composting techniques are much safer and more effective alternatives for vegetable gardening.
Does cat urine harm vegetables and plants?
Yes, cat urine can harm growing plants, primarily due to its high concentration of ammonia and urea, as well as other factors that affect soil health and plant growth. Here’s how cat urine can negatively impact plants:
1. High Ammonia Content:
- Ammonia Toxicity: Cat urine contains a significant amount of ammonia, which, in high concentrations, can be toxic to plants. Ammonia burns the roots and foliage of plants, causing damage that leads to browning, wilting, or even death. Sensitive plants may show symptoms of stress soon after exposure.
2. High Nitrogen Content:
- Nitrogen Burn: Cat urine has a high nitrogen content in the form of urea. While nitrogen is essential for plant growth, too much of it, especially in concentrated forms like cat urine, can overwhelm the plant. This leads to “nitrogen burn,” characterized by yellowing or browning leaves, poor root health, and inhibited growth.
- Imbalanced Nutrition: Excessive nitrogen from urine can also upset the nutrient balance in the soil, promoting too much leafy growth at the expense of fruits and flowers.
3. Soil Salinity:
- Salt Buildup: Cat urine can increase the salinity of the soil over time. High salt levels can harm plants by interfering with their ability to absorb water through their roots. This can lead to dehydration of the plant, even if the soil appears moist. Over time, high soil salinity can cause long-term damage to the soil structure and reduce fertility.
4. pH Imbalance:
- Acidification of Soil: Cat urine tends to be acidic, and if it is repeatedly deposited in the same spot, it can lower the pH of the soil, making it more acidic. Acidic soils can negatively affect the availability of certain nutrients, limiting plant growth. Many vegetables and garden plants prefer neutral to slightly acidic soil, so a shift toward higher acidity may harm them.
5. Localized “Hot Spots”:
- Concentration of Nutrients: Cats often urinate in the same spots, which can lead to localized areas with very high concentrations of nitrogen, ammonia, and salts. These “hot spots” can kill or severely damage any plants growing in the affected area. Over time, repeated urination can create patches of barren soil where nothing grows.
6. Root Damage:
- Direct Damage to Roots: The high concentrations of urea and ammonia in cat urine can damage plant roots on contact, causing them to become less efficient at absorbing water and nutrients. This leads to stunted growth and can eventually kill the plant if the roots are severely damaged.
7. Odor and Attraction of Other Animals:
- Odor Issues: The strong smell of cat urine can persist in the garden, and the lingering odor may attract other animals or even more cats. This could lead to more frequent urination in the area, compounding the damage to the plants.
- Contamination: The urine could also contaminate edible plants, making them less appealing or even unsafe to consume, particularly if there is any risk of zoonotic disease transmission from the urine.
8. Impact on Soil Microbiology:
- Disruption of Beneficial Microorganisms: High concentrations of ammonia, salts, and acids from cat urine can disrupt the balance of beneficial microorganisms in the soil. These microbes are essential for nutrient cycling and healthy plant growth. If their populations are negatively affected, soil fertility and plant health may decline.
Conclusion:
While a single instance of cat urine on plants may not cause significant damage, repeated exposure is likely to harm growing plants. The high levels of ammonia, nitrogen, salts, and potential acidity can cause root damage, nutrient imbalances, and even plant death over time. If you have a garden or plants in an area where cats frequently urinate, it’s important to manage the issue to protect the health of your plants.
