Yard work: how I fertilize the lawn

Self-tutoring about yard chores: the tutor mentions some details about how he applies fertilizer.

The following is according to my understanding.

After one buys fertilizer, one must decide how much to apply to the lawn and then exactly how to do so. Here’s what I do:

• Connecting with my post from June 16, 2023, I only fertilize when the lawn is actively growing.
• I estimate the length and width of the lawn, then multiply them to estimate its area.
• Next, I read the bag of fertilizer for how much I should apply per square unit. Then, I multiply the estimated area by the amount recommended per square unit (same square unit as area is in) to determine the quantity to use; I will refer to that quantity as Q.
• Q is a measure of mass, but I don’t use a scale or balance. What I do, first, is estimate the mass of the fertilizer left in the bag, as follows: Based on the remaining volume in there compared to what the volume was when it was full, I determine the proportion of the fertilizer remaining. Then, I multiply that by the mass printed on the bag to get the mass remaining, which I will call M. Next, I compare Q to M: assuming Q < M, I imagine that ratio and try to pour that much out of the bag into the spreader.
• I use a drop spreader to apply the fertilizer. (More on that, perhaps, in a future post.) I don’t have a way to measure, numerically, the rate at which the fertilizer drops from the spreader onto the lawn. However, I can control how quickly it drops. Therefore, I set the spreader to drop the fertilizer thinly, then walk the entire lawn repeatedly until all the fertilizer has dropped from the spreader.

With so many estimates involved, the process is likely rather imprecise. I try to stay on the lower side with my estimates, with the idea that one can fertilize again later if appropriate.