What Manure is Best? (part1)

Horse, cow, rabbit, sheep, goat, hog, duck, chicken, turkey, etc. What's the best value for money? In this two-part series I show how it's not as simple as one might think!

I recently purchased two cubic yards of well-aged manure, and have been gradually working it into my garden beds over the past few weeks. It’s getting a bit late in the season for the application of manure, but for me, as long as the soil isn’t frozen there’s work to be done - so I will persist in this task until the season puts an end to things. As a result of that activity, the topic of manure has been on my mind lately, and in particular, the question of which manure offers the best value for money.

Is there anything more satisfying than adding manure to a garden. It’s almost like turning poop to gold!

A few points on value

There are many ways to think about value, so I think it is worthwhile to take a minute to flesh out exactly how I intend to use that term in this article. When sourcing manure, or any other gardening input for that matter, value is the ratio of content to cost; or, in other words, how much are you getting relative to how much you have to give. In the case of manure, a simple way to think about content is to see it as a function of total volume (e.g. cubic meters/yards) and total nutrient content (i.e. NPK). For cost, there is the cost of the manure itself; there is a the cost of delivery, or the cost of travel required to collect it; and there is also the question of the time-cost that might be required, such that hours of driving might be required to get to a farm outside of town that sells manure. In this sense, one manure might cost $50/yard with a $20 delivery fee; whereas another might be $20/yard but it is pick-up only, and is two hours outside of the city, such that collecting the manure will take 4+ hours and a half-tank of gas… and that’s assuming that one has a truck or trailer to transport the manure. If those need to be rented then the cost runs higher still.

With the above consideration in mind, I would like to start by saying that the closest and cheapest manure is ALWAYS the best choice, since all manures are generally good for the soil¹. Moreover, for anyone with no truck or trailer, it is almost always cheaper to have it delivered; and when having it delivered, to buy as much as possible since the delivery cost is usually independent of the quantity being delivered. Also, buying in bulk (e.g. by the cubic yard) is always a better deal than buying in bags. Finally, aged manure is always preferable to fresh manure, because it is more dense, will have more available nutrients; will have fewer pathogens²; and it will (generally) have less viable weed seeds.

A (long) note on “weed-less-ness”

I have read many articles explaining how some manures have less weed seeds than others, but in general, it is very difficult to eliminate weed seeds from manure.