Fertilizer
"The lowing herd winds slowly o’er the lea...,
And leaves..."
"Elegy in a Country Churchyard"
Thomas Gray
"What is that stuff?"
"Don’t step in it!" Fertilizer.
Organic, chemical, lawn, rose, vegetable, flower, acid, weed-and-feed and bull...um, manure. Good question. What is fertilizer?
There are only three things of consequence in any kind of fertilizer–nitrogen, phosphorus and potassium. NPK (the Latin for potassium or potash starts with a "K" for some reason). Plants utilize a host of chemical elements, but most soils contain a life-time supply of the micro-nutrients such as zinc, iron and molybdenum. Generally, the three chemicals which serve as bottle-necks to growth are these–NPK.
The Federal Bureau of Fertilizer and Paper-work requires that the percentage by weight of each element–NPK–be clearly stated on the sack. Thus, when you ask some adolescent at the garden center for fertilizer to put on your vegetables, the response will often be, "5-10-5?" That is 5% nitrogen, 10% phosphorus and 5% potassium by weight. The correct answer would be, "Yup," or, "Shurr." But suppose you were offered a choice between two strengths of fertilizer; which one would be more suitable, 5-10-5 or 15-30-15? The correct answer would be, "Wulp, which of ‘em is cheaper?" In the fertilizer biz, proportions count for everything and these two sets of numbers are in exactly the same proportion. 10 is exactly twice as large as 5 and 30 is exactly double 15. Of course, the higher concentration of fertilizer in this example is twice as strong as the lower one. So yo can use only half as much to get the same result. Or use two handfuls of the weaker mix to equal one handful of the stronger stuff. The plants do not care. There can be quite a price difference on a value-for-active-ingredient basis.
Should you opt for a complex, organic fertilizer–cow end-use product, processed sewage sludge, crab waste, blood meal or that triumph of Gothic suggestion, tankage? Read the numbers and go for the price per pound of active ingredient–NPK. The percentages of NPK found in manure, et al, are surprisingly low. A lot more organic 1-3-0 is needed to equal one sack of chemical 5-10-5. There are ethical, nay moral arguments in favor of organic fertilizers put forth by the advocates of organic gardening. Not having a bean-pole handy, I will not touch them here. But organic fertilizers do indeed have a functional advantage in the way they provide slow release of such nutrients as they do contain; the way they build soil, making it more friable; the concomitant increase in beneficial microscopic soil life and the addition of a wider range of micronutrients. But it is a fallacy to scowl at the 5-10-5 for bearing the, somehow, nasty-sounding name, "chemical," when rabbit pellets contain exactly those same chemicals. If some horse or chicken owner offers a load of manure, snatch it up as the gift of a prosperous garden.
There is no such a thing as lawn fertilizer or rose fertilizer, not really. Lawn fertilizer is just high-nitrogen mix. Rose fertilizer generally has a high proportion of phosphorus. Each nutrient is used primarily in a different part of the plant–nitrogen in leaves and fruit, phosphorus in stems and potash in root systems. But these generalizations can be misleading. In any case, "rose," fertilizer will grow pretty good flowers, shrubs vegetables and Africanviolets. A few handfuls of "lawn," fertilizer will stimulate the bacteria to rot your compost pile down like nobody’s business. Read the label on the fertilizer package, but don’t let it boss you around. You have to be alert for BS at every turn.
appeared July, 2001