Turf & Rec

Features Agronomy
Making sense of the numbers, part 3

June 12, 2012
By Mike Jiggens


By Sean R. Jordan, T.Ag.

In this final installment of the Making Sense of the Numbers series on
understanding the figures associated with fertilizers, we are going to
dissect the cost of fertilizing. Not only will we be discussing the
price of the product itself, but also the labour and intangible values
such as performance and additional benefits.

A common oversight that many fertilizer purchasers make is to buy a product based on the price per bag. There are many aspects to consider when looking at the actual value of a bag of fertilizer, including weight, analysis and the ingredients used to formulate the product.

In terms of weight, something we have going for us here in Canada is that most of the professional fertilizers come in 25-kilogram bags. This is roughly 10 per cent more product than the 22.68-kilogram bags our neighbours in the U.S. use. This becomes an issue when a consumer neither notices nor considers the weight of the products brought across into the Canadian market from the U.S. A 22.68-kilogram bag of fertilizer from the U.S. may cost 5 per cent less than its 25-kilogram Canadian counterpart, but if you don’t notice the actual weight, you will be getting around 10 per cent less fertilizer per bag.


Another common “price-per-bag” shopping mistake is not taking into account the area a bag will cover. One way to ensure you are getting the most for your money is to calculate the cost per unit area or coverage of each product you are comparing based on their analyses. For this example, let’s say that you intend to apply 0.5 kilograms of nitrogen per 100 square metres (~1 pound/1,000 square foot) and two products you are considering have analyses of 33-0-0 and 20-0-0 at costs of $38 and $23 per 25-kilogram bag, respectively.

To achieve the desired amount of applied nitrogen, you would need to apply 1.5 kilograms per 100 square metres of the 33-0-0 product and 2.5 kilograms per 100 square metres of the 20-0-0 product. Given the specific analyses, rates and cost, you can calculate that the 33-0-0 product would cost $2.30 per 100 square metres and the 20-0-0 product would cost $2.30 per 100 square metres. You may look at those numbers and think that there is no difference, but it is also necessary to consider that ~64 per cent more 20-0-0 product will be needed to cover the same area as the 33-0-0. That translates into higher shipping costs, more labour to handle and apply and greater storage space required.

Additional consideration should be given to the ingredients in the product. Let’s look at the two formulations from our first example to see how differences in nutrient sources impact the value of a fertilizer. For this example, the 33-0-0 product contains 50 per cent slow release nitrogen from methylene urea and the rest from pure urea and the 20-0-0 derives half of its nitrogen from a polymer-coated, sulphur-coated urea with the remainder, again, coming from urea. If equal amounts of nitrogen are applied from each of these products as in the previous example, the growth and colour response from the 33-0-0 is likely to last at least one month longer than the 20-0-0. Again, as with the coverage differences above, the product with the greater longevity would need to be applied less often and consequently would result in less labour and area needed for storage and possibly even one fewer application through the growing season. 

For some of you, the approach in the previous example that places higher value on slow release nitrogen may not be applicable. For instance, many golf course, cricket pitch and bowling green managers would prefer spoon-feeding or appling smaller amounts of nitrogen more often to afford them a different type of control than the less frequent, higher-rate applications of primarily slow release nitrogen.

Relatively speaking, however, these areas are small in comparison to the surrounding turf areas, and are of much higher value so a turf manager could possibly justify a higher labour rate for the maintenance of these areas, provided that the results are favourable.

For the larger areas such as golf course roughs, park open spaces and some sports fields that have considerable acreage, the value of a higher percentage slow release nitrogen fertilizer that results in less surge growth and less frequent cutting is in the labour savings and better overall quality over time. When you take into consideration the maintenance costs (mowing, fertilizing, etc) of larger areas, the difference in price is more than recuperated.

Another common place where slow release fertilizers are undervalued is in professional lawn care. An expectation that has been developed over time is for the homeowner to see his lawn care provider visit on a regular basis. In too many cases, this has created a culture of using cheaper fertilizers with lower amounts of slow-release nitrogen that need to be applied more often to maintain desired colour and growth. Again, a cost not often considered in this approach is handling, application and storage. The value of using a fertilizer with more slow-release nitrogen in this case would be that the operator could make fewer applications throughout the growing season, allowing for one or more visits to do special maintenance practices that will also make a large impact on the appearance of the lawns and add value to their services.

I hope that this article and the two before have provided some insight into making decisions about the types, sizes and compositions of fertilizers to use for your various turfed areas. It should be clearer now that the costs associated with the fertilizer applied to turf go well beyond the price of the fertilizer and taking the time to research the product that best fits your needs will produce better overall results as well as save money spent on labour, transportation and storage.