February 24, 2021

Compost is my soil amendment of choice. In terms of soil fertility and revving up Soil Food Web activity, compost is arguably the best input you can use on your farm or garden. Since compost is plant matter that has been decomposed by beneficial microorganisms, when you add compost to your garden, you are effectively adding billions of beneficial bacteria, protozoa, nematodes, fungi, etc. to aid your garden in synthesizing nutrients and combating diseases.

All of that is great, but when we outsource our compost from a municipality or another farm, we have to be aware of the risks involved in doing so.

Before I get into my experience with outsourcing compost and manure, I will encourage the fact that using your own, homemade compost is the absolute best soil amendment you can use on your garden. Because you have complete control over what goes into the pile, you know the end product is healthy, weed-free and chemical-free. We do not have any control over those factors when we outsource compost.

risks involved with outsourcing compost

1) There is no telling what chemicals and toxins are present in the compost. This is especially true if you gather compost from your municipality or if you have it delivered from a local top soil company that also sells “compost.” Many times, this compost from the top soil place will be sourced from the municipality so they are simply acting as a middle man.

Municipal compost is made from everything people throw in their landscape bins, and from what the street sweepers gather up during fall leaf clean up. This means that municipal compost pile is full of leaf litter, grass clippings and garden cuttings from thousands of suburban yards that have been treated with herbicides like RoundUp, “shaken” herbicides like Preen, bee killing pesticides, and other extremely harmful chemicals. Beware of municipal compost. In some cities it’s even free, but you do not want this added to your edible garden where you and your family will be ingesting plants grown in that compost.

2) The compost might arrive full of garbage. Yes, garbage. A few seasons ago I ordered compost from a local topsoil supplier in Lockport. To my dismay, the “compost” was full of huge cinder block pieces, plastic bags, foil, Legos (?), pieces of wire cabling, and even socks. Yes, socks that humans wear on their feet. The whole pile had a distinct motor oily smell to it.

This place in Lockport is not the only time I’ve experienced garbage-laden “compost.” When I worked for an organic gardening company in Chicago, a few of the compost dumps had garbage in it with that distinct motor oil odor. Beware of adding anything like this to your edible garden.

3) You will introduce new, aggressive weeds. This has happened to me, in unforgiving ways, on my flower farm. Due to outsourcing compost and cow manure, I have introduced extremely invasive weeds such as mugwort, motherwort, dead nettle, lamb’s quarters, purslane, and a slew of grasses, among other weed species. Because I could not control which plants were being composted and whether or not they had already gone to seed, I brought all kinds of new species onto my flower farm that I will now fight with forever.

4) You will introduce new bugs. I don’t feel this is necessarily a terrible thing, but depending on the insect species, it could be. The new insects I’ve inadvertently introduced have not brought the wrath that other species could have. I now have giant (I mean giant) wolf spiders, praying mantises, and many species of lady beetles that I hadn’t noticed before. Bugs also become more diverse when the landscape becomes more diverse, so it’s hard to say which species were brought in with the outsourced compost and manure.

I still think the potential of introducing new bugs is a risk, especially with municipal compost. This is because of the invasive jumping worms (aka ‘crazy worms’). These worms are an invasive species in the United States and effectively kill native earthworms, along with plants and trees. Once they’re in your garden, they are impossible to eradicate as they multiply at an incredible rate. I’ve seen them with my own eyes while working on landscapes in Chicago, not knowing what they were until I did some research. Because of the rampant threat of this worm, I will never, ever outsource compost again.

I hope this article, while a bit dark in content, shed some light on why outsourcing compost, soil and manure can be problematic for your growing space. I encourage you to learn how to make your own compost, which can be as simple as throwing all of your healthy yard and kitchen scraps into a pile and letting nature do its thing. It is the absolute best way to “fertilize” your garden.

peace, love and plant magic,

Fran Parrish