this is just me thinking and not fact but I would think that the heat of the composting would break down some if not all of the chemicals. I dont know maybe it doesnt get hot enough.

Dawn is pretty smart on that. i remember reading how she lets hay sit for awhile away from everything to see if the chemical leach into the surrounding areas and kills anything. Of course the hay is in its pure form and not composted so I dont know if that would work for your situation.

I will say this. we covered our garden with about 4 inches of wood chips from the Tulsa green waste site and we had no ill effects on the plants.

Mike

I have used compost from the Ft. Smith Landfill. It is my last choice of organic matter because it contains so many pieces of shredded plastic bags. I have had good luck from the soil amended with it, but the plastic blows out into the lawn and hangs up on the tiller tines. The plastic seems to never go away.

Larry

In my town, it is chopped limbs and a little of everything else. I don't plan to use it again, but if I did, I would use it to make compost, not to use as compost. It was closer to rough mulch than it was compost.

No experience with it here. Wish I could help.

George
North of Tahlequah

I have no experience with municipal compost, but I'd be very hesitant to use anything at all from an unknown source. Here's why: contaminated compost, aka killer compost.

I wouldn't be worried about pathogens, heavy metals, etc., if they say they are testing for those items and their compost tests clean of those residues. (Keep in mind that a clean test usually only means that whatever they are testing for falls below a certain threshold, it doesn't mean that they guarantee there is 0% of those items in the compost).

Contaminated compost, i.e. killer compost, is a very legitimate issue and a very real issue. Every year there are gardeners who unintentionally introduce herbicide residues into their garden and kill their plants. The worst part of all this is that the problem herbicides can take several years to break down to the point that you once again can grow plants in that soil. I have no words to express how upset I would be with myself if I accidentally contaminated garden soil we've spend years building up and improving.

The herbicides that break down slowly have been banned or voluntarily withdrawn from the market in some countries, but not in the USA, so we all have to be really careful about bringing in outside material and putting it in our gardens. One thing that bothers me about the thought of using city compost is that, in an urban setting, these herbicides are commonly used on city parks (to keep the grass free of broadleaf weeds) and on golf courses (for the same reason). So, to me, the risk of getting contaminated compost is higher if your city has city parks and golf courses that it maintains. Nowadays what city doesn't have parks? So, the question becomes this:

How much of a risk are you willing to take? Can you cope with not being able to grow most edibles and broadleaf ornamentals for several years if you inadvertently introduce contaminated compost to your garden? How long your soil will remain contaminated will depend on several factors and is unpredictable, but most people who have had this happen have found themselves unable to grow anything but grassy plants for at least 3 years.

The herbicide residues can contaminate soils even at a very low level. These herbicides survive going through the intestinal tract of animals, they survive being composted, they survive for several years in your garden. So, using city compost is a huge risk, and I mean no disrespect for any city when I say that. It is simply the way it is.

If you feel like you are willing to take the risk, then at least test the compost after you bring it home and before you add it to your garden. It is easy to test for herbicide residue contamination and I'll link an article that tells you how.

I don't use city compost and I rarely buy bagged compost any more, but I use old hay and straw given to me by ranching/farming friends. I am ultra-cautious and let it sit and decompose for at least a year before I use it. Even though my friends don't spray their hay pastures with any of these persistent herbicides, most of them buy some hay every year (and in bad drought years they buy tons and tons of hay) and they have no way of knowing if that hay contains residues. For that reason, I stopped using manure offered to me by ranching friends and neighbors because the likelihood of their animals' manure containing these residues is very high. I don't even use my own chicken manure from our henhouse in a compost pile that makes compost for our edible garden any more because we have learned in recent years that the manure from animals fed name-brand conventional animal feeds can contain these residues at high enough levels to kill gardens. Instead, I use the manure cleaned out of the chicken coops on a compost pile that makes compost that only goes into ornamental beds. I've never lost an ornamental plant to anything that looks like herbicide damage, but if it ever happens, I'll just start taking the chicken manure compost and feeding it to the Johnson grass on the edge of the woods. That Johnson grass tries to creep into my garden constantly and it drives me up the wall. Maybe I need to feed it some city compost and see what happens!

I want to second what Larry said about plastic remnants being in many municipal type composts. That is really common and I wouldn't want to add shredded up plastic to soil either. You might be able to get around that by using a compost sifter to remove all the bigger bits of plastic but you probably can't get all the little ones that are small enough to go through the sifter screen.

Having said all of the above, if you are willing to bear the risk, I say go for it. It is hard to make enough compost in a backyard pile to feed your garden as much compost as it needs, so I don't blame anyone for wanting to bring in municipal compost. Just be sure to test it first using peas and beans. If they grow and don't show signs of contamination damage, you can be reasonably certain that there are not high enough levels of herbicide residue to harm your plants.

You know, you could use it strategically in half your garden this year. Make sure it is the downhill half so water runoff cannot carry the residue down into the half of the garden where you didn't use the compost. That way, if you do inadvertently contaminate your soil, you've only contaminated half of it. You still could grow some plants in the residue-contaminated half in the following year. Since the herbicides that cause problems are designed to kill broad-leaf weeds, you could raise corn in the contaminated soil, or other plants that have grassy leaves, not broadleaf weeds.

I agree with Carol's statement, too, about using it to make compost. Most municipal compost is not finished compost. It is more like partially decomposed mulch.

Here is a link that might be useful: Simple Test For Herbicide Residues in Compost

Dawn, How do you remove your Johnson grass? My son has so much of it at his place, and we need to start dealing with it.

Thanks for all the replies everyone. I bought some anyway and will test it out on some peas to check for herbicide. I will probably only use it on the flower beds and to level out a low area on the property even if it turns out to be clean. I think I will just feel better about it if I forgo applying it to the veggie garden.

Carol, I hand-dig it. It is an endless job. Sometimes I dig out stolons that are bigger around than my thumb. If I repeatedly dig it out every winter before I plant, and if I relentlessly dig it up when it resurfaces in the summer, I can keep the garden fairly free of it. The problem is that it grows rampantly on property line next door, so there's an endless supply of hungry stolons growing under the fence and popping up in my garden. I'll never be entirely free of it. It is bermuda grass on steroids.

Trouble, in the form of new Johnson grass, always rears its head at mid-summer when I've had a couple of encounters with venomous snakes in the garden,no matter how hard I've worked to keep the garden free of it. Once those snake encounters start happening, I slack off on garden maintenance and just go into the garden long enough to carefully harvest without getting bitten by a snake. That usually gives the Johnson grass a chance to regrow because I'm not out there actively fighting it. I have some success keeping it out of the beds (or at least out of sight) if I put down heavy-duty fabric mulch cloth at planting time, cover it with mulch, and plant through holes cut in the fabric. It slows down the Johnson grass but doesn't stop it. The Johnson grass creeps and crawls under the fabric but on top of the soil directly beneath the cloth and comes out where holes were cut and plants are growing. I have found Johnson grass stolons growing 20-30' long on top of the ground but beneath the fabric mulch cloth. When I lift the cloth after the infested beds are through producing in the fall, I pull out long ropes of Johnson Grass stolons. It makes me crazy. I don't even attempt to compost them. I just put them in black trash bags for Tim to haul to the dump with the rest of our trash. In the winter I lift the fabric off all raised beds and pathways and dig out all the rhizomes as deeply as I can. It is very hard to do that with the clay. In the new back garden, it is a whole lot easier to remove the rhizomes in the sandier soil. I may have success mostly keeping it out of the soil there. So, if your son has sandy loam, the Johnson grass might not be as much of a problem. It seems to favor dense compacted soil that is low in organic matter, but it still likes my improved clay too. It doesn't seem to like my sandy areas much.

If there is a chemical herbicide that will kill Johnson grass, I probably wouldn't use it anyway, but I've never heard of one that works.

Belafonte, When the first round of contaminated compost hit around the year 2000 or so, it was a huge shock to the organic world. The idea that a herbicide could survive the composting process at high enough levels to kill plants for several years thereafter was mind-boggling. Here we are more than a decade later, and it is an even more widespread problem now than it was then.

I think it is important to be careful with anything we bring onto our property. I'm glad you're going to be careful with what you add to your garden. I have read many accounts of people who inadvertently contaminated their soil by bringing in herbicide-contaminated compost and it makes me sick on their behalf. Sometimes they talk about it on various forums here at GW. Hindsight always is 20-20 and they always wish they could go back in time and not use the compost or mulch that killed their gardens. This is one of those areas where you cannot be too careful.

I hope you'll come back in a few months and tell us how the compost worked out for you. Remember that "heat eats compost" and we have plenty of heat, so adding compost is a constant job. It amazes me how quickly the compost goes away, but then it is doing its job and breaking down and being used. If i miss adding compost to any of my garden beds in any given year, I sure can see the difference in poorer plant performance.

Dawn