I have to admit to being speechless when someone recently asked about using urine as fertilizer.
I wasn't surprised at the question, but I was taken aback by the seemingly calm acceptance of this idea.
I totally understand the concept of using coyote urine to keep deer out of the bean patch or fox urine to repel rabbits from the lettuce rows. After all, these animals are predators and what better way to keep the vegetarian pests at bay than to make them think what is hunting them is one footprint away from the garden gate. But I have to draw the line somewhere and that line is at my own bathroom door.
Proponents of using urine as fertilizer claim it is not only ecologically beneficial, but that human urine contains all the nutrients necessary for healthy plants to thrive. While the water savings alone could be astronomical just from less flushing, it can't be accurate when it comes to determining the three main components in fertilizer, nitrogen, phosphorus and potassium.
I also have to wonder about the antibiotics, hormones, anti-depressants, cholesterol and other drugs so many of us are taking these days, and how our plants might react to those chemicals. We've all heard the reports of our rivers and streams being inundated with synthetic drugs and have read the dangers of flushing leftover drugs into our septic systems. Doesn't it make sense it would make the problem even worse if we were pouring these pharmaceuticals on our plants?
Some might argue that urine is less expensive than fertilizer, enabling the gardener to save money. Urine, after all, is free, not to mention that it is always available.
I equate using urine as fertilizer along with other home remedies, such as using cayenne pepper and dishwashing liquid as an insect repellent. You can find recipes for all sorts of garden home remedies using basic household items. But nowhere on a bottle of dishwashing liquid are directions for use on plants. There is nothing about a bottle of beer that would make me want to pour it on my lawn, nor am I reaching for the epsom salts when planting roses.
When looking at commercial fertilizer for use in the garden, you can't go wrong if you read the manufacturer's directions. These are the guys who held trial after trial to get the right combination of nutrients.
Those three numbers on the label, separated by dashes that represent NPK, are units of measure by weight. For example, if your package of fertilizer is listed as 5-10-5, this means that by weight, five percent of the ingredients is nitrogen, 10 percent is phosphorus and five percent is potassium. In other words, in a 10 pound bag of fertilizer, one-half pound is made up of nitrogen, one pound is phosphorus and one-half pound is potassium. The remaining 80 percent (or eight pounds) could contain trace minerals and micronutrients, but it is mostly filler. This filler material is important. It allows us to evenly distribute the fertilizer and keeps us from applying too much or too little of the nutrients.
If you've done the math, you might be wondering if using 10-20-10 in place of 5-10-5 would make much difference. Other than the amount of distribution, those fertilizers are exactly the same.
Nitrogen is needed for foliage growth. Phosphorus is needed for roots and the setting of flower buds and potassium feeds the plant overall, not only helping it build resistance to pests and diseases but enabling it to deal with imbalances in the environment, such as drought.
A fertilizer that contains all three major nutrients is called a "complete" fertilizer. When you see a label marked 0-10-10, this means the product doesn't contain nitrogen. This is an incomplete fertilizer.
Organic fertilizers, like fish emulsion and bone meal contain no synthetic materials. Organic fertilizers often have lesser amounts of NPK and you will probably have to feed your garden more often and use more of it.
When it comes to fertilizers, there is no one size fits all. The best way to find out what your soil needs is to do a soil test. Test results will keep you from adding all sorts of chemicals you don't really need.
You can't go wrong by using lots of compost in your garden. This will not only add micronutrients that work with NPK to keep our plants healthy, but it will loosen the soil so that water and oxygen can get to the plants' roots.