It’s tax season. It’s also the time of year we refer to as “mulch madness.” These two seemingly unrelated events dovetail into some earthy calculations.

The query: What’s the return on investment (ROI) for mulch?

We know, inherently, that mulch is “good”: it reduces weeds, maintains soil temperatures, retains moisture, and enhances the soil. But what is its value?

Well calculations will vary depending on a range of factors (e.g. amount of time to initially prune, cost of mulch, time it takes to apply it, appreciation for beauty, seasonal and product variation and how it interacts with the landscape, etc). But let’s toss those quibbles aside, make some assumptions, and try to provide some shape around this notion.

First, let’s look at the scope of the case study in the following video of a “Tree Pedicure”:

It took about 20 minutes to do a tune up on this tree: trimming suckers, removing vegetation to the drip line, and adding a 3” layer of mulch spread evenly away from the trunk. This includes pulling out supplies and tools and getting organized, and putting away tools.

Next, let’s refresh our memories on how to calculate return on investment, or ROI. In short it’s the (gains – investment costs) / (investment costs). Written out, it’s the gains minus the investment costs, divided by the investment costs.

So, for example, if I sold orange juice for \$8 (my gains) and it cost me \$4 to make it (my investment costs), my ROI would be (\$8-\$4 / \$4) = 1, or a 100% ROI.

Finally, let’s dive in and look at this case of applying mulch. Using really broad and fast brushstrokes, here are the background metrics for the calculations.

Investment Costs:

• Time (20 minutes, with time valued at \$60/hr to make math easy): \$20
• Materials (2 bags of mulch, with a very generous budget): \$10
• TOTAL INVESTMENT COSTS: \$30

Gains:

• Time (since the mulch will repress weeds, one gains back the time not needed to weed throughout spring and summer, estimating 5 minutes per month for the next six months: \$30
• Look (how much one would pay to look out over a pretty landscape; say \$0.10 per day for six months): \$18
• Nutrients added to soil slowly over time (yikes. With no idea how to calculate this. Let’s give it a small value): \$2
• TOTAL INVESTMENT GAINS: \$50

So the ROI on this particular project is…drum roll please… [(\$50-\$30)/\$30] = 66%.

A 66% ROI is stunning.

This example is, of course, an example. It’s an illustration. It’s a way to think about the time and money that you could spend this spring tuning up your landscape and applying mulch – while weeds are still small! – and how much gain, or return, you could experience from that investment.

Have tips on how you would tweak these calculations?  Please share!