I use organic fertilizers rather than chemical fertilizers, such as 10-10-10 (10 percent nitrogen, 10 percent phosphate, 10 percent potash) because my tiny urban farm is within easy strolling distance from downtown skyscrapers and little Ellerbe Creek, in Durham, N.C., which leads to a drinking-water reservoir. The main benefit for the organic garden is that organic fertilizers provide dozens of nutrients that our flowers, fruits and vegetables need. Chemical fertilizers might be less expensive, but they often provide only three nutrients: nitrogen, phosphorus and potassium. Like people who eat only cheeseburgers and milk shakes, this kind of diet leaves many plants with a weakened immune system, putting them at risk of bug and disease infestations. It’s no surprise that landscape-maintenance companies that use chemical fertilizers also offer spray services for bugs and diseases.
Chemical fertilizers are also very similar to table salt: Put too much near the roots of a plant, and the saltiness will suck the moisture from the roots, making the leaves appear burnt. Even when applied safely to plants, these salty fertilizers can contribute to other problems. Like table salt, they dissolve in rainwater and some percentage washes out of the garden and downhill into creeks, ponds, reservoirs and oceans. An excessive amount of nitrogen or phosphorus in these waterways causes algae growth to explode and kill fish. Pound for pound, organic fertilizers are much less likely to wash away. More of their nutrients end up where they’re intended — in your garden plants — and fewer fish suffer.
The sources of these two kinds of fertilizers are also very different: Organic fertilizers may come from crops (alfalfa meal, soybean meal), quarries (rock phosphate, greensand) or waste from slaughterhouses (bone meal, feather meal, crab meal). Chemical fertilizers, on the other hand, rely on large quantities of fossil fuel to extract nitrogen gas from our atmosphere to create nitrogen fertilizer. There’s no shortage of atmospheric nitrogen, but other problems are found downstream from this process. Burning fossil fuels to make fertilizer puts more carbon dioxide in the air, which contributes to climate disruption: hotter summers, longer droughts, harsher winters, etc. The weather is already a challenging enough element of gardening without us rocking the climatological boat.
So how do we use organic fertilizers? When planting a new plant, I add one fistful to the planting hole for a vegetable or perennial, two fistfuls for a shrub and three fistfuls for a tree.
I can’t do that with chemical fertilizers because they will burn the plant. I also sling handfuls of organic fertilizer on the soil around established plants every winter before mulching, and I spread some on our little patch of lawn in early spring. At this point, we’re likely to stroll down to Ellerbe Creek to see how the tadpoles, minnows and crawdads are doing.
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