# How to save 60% or more in turfgrass fertilizer cost

Do you ever think about fertilizer cost? The amount people spend varies *a lot*.

Jason Haines, for example, has explained how he reduced fertilizer costs by 60%:

I have to say, this new way of doing things is working a lot better than the old way. I have cut my fertilizer budget by 60% and have drastically increased the quality and health of my putting surfaces.

Jason has explained how he can fertilize greens for $25/acre/month. One could also spend more. For example, at the same time Jason was writing about his costs, I saw this advertisement for fertilizer in Thailand, offered at a price of ONLY 38,400 Thai baht per hectare per month (USD 1,243, or about USD 503 per acre).

With such a huge (more than 20 times) difference in fertilizer cost, I began to wonder, just what is the cost^{1} when using soluble fertilizers and applying them in precise amounts based on plant demand.

To determine approximately how much nitrogen any turfgrass will use, we can use the temperature-based growth potential. Then, we can apply urea or ammonium sulfate to supply the necessary nitrogen. Phosphorus and potassium should be applied based on the result of a soil nutrient analysis. Let’s make a quick calculation of annual fertilizer cost, using the growth potential model for nitrogen and using a typical situation in which soil phosphorus is adequate to meet plant requirements and in which potassium will be applied at half the rate of nitrogen.

We can consider the cost to apply fertilizer to creeping bentgrass at Osaka. I choose Japan because it has relatively high fertilizer prices. There, the price of urea is ¥2,450 for a 20 kg bag, and potassium sulfate is ¥2,500 for a 20 kg bag. Using the growth potential model, we predict an annual N requirement of 20 g/m^{2}, and for K we will apply 10 g/m^{2}. Assuming a green surface area of 10,000 m^{2}, the annual fertilizer cost for the greens will be ¥81,119. With exchange rates at the time I wrote this [September 2012], that is equivalent to an annual cost of USD 1,031. And that is a cost of USD 417/acre/year.

Making these calculations for a tropical location—bermudagrass at Bangkok, Thailand—the grass may use about 44 g of N/m^{2}/year, and the urea cost in Thailand is 328 baht for 20 kg. Potassium sulfate is 640 baht for 20 kg and we will apply 22 g K/m^{2}/year. Assuming green surface area of 10,000 m^{2}, the annual fertilizer cost for the greens in Thailand, using these products, will be 31,377 baht. With September 2012 exchange rates, that is equivalent to an annual cost of USD $1,016. And that is a cost of USD 411/acre/year.

With the money spent on the branded fertilizer at ONLY 38,400 baht per month, one could fertilize bentgrass greens at Osaka, or bermudagrass greens at Thailand, for more than a year. That is something to consider when you are choosing which fertilizers to apply.

I wrote this post and made these calculations in September 2012. ↩︎