Plants Forbidden For Compost?

bob64(6)January 21, 2008

The thread on "Help on a couple of questions please" has inspired me to post these questions:

(1) What plants (and fungi, etc.) should never be used (or only sparingly used) for food crop compost due to their poisonous, toxic or otherwise unhealthy nature when the food is consumed?

(2) What plants (and fungi, etc.) should never be used (or only sparingly used) for any compost due to toxic effects on the plants that you wish to grow with the help of the compost?

P.S. Regarding question (2), I have already heard that Walnut, Ailanthus and Norway Maple all have alleopathic properties but I am sure there are other plants of concern or open to debate.

Thank you for reporting this comment. Undo
joepyeweed(5b IL)

Technically, a complete and finished compost has decomposed any ingredients into their base chemical constituents such that, they no longer retain the toxic properties of their previous compounds.

That being said, a lot of people use partially finished compost or compost in place... and then one might want to be more prudent about what goes into the pile.

I personally won't compost Poison Ivy, because I am very allergic to it. I am not concerned about poison ivy urishol in finished compost, but I am concerned about possibly contacting it, while working with the pile, before it is finished. I don't want the urishol on my tools, on my gloves etc.

I have composted walnut leaves, but they were a very small component of many different types of leaves and the compost was finished and aged before it was used.

    Bookmark   January 21, 2008 at 5:01PM
Thank you for reporting this comment. Undo
whip1 Zone 5 NE Ohio

For me, it's poison ivy. Besides the fact that I don't want it in the pile, I have no idea how to get it into the pile. It's one of the few times I use Round up.

    Bookmark   January 21, 2008 at 5:45PM
Thank you for reporting this comment. Undo

Among other things, I was wondering if some plants that are poisonous when ingested directly (like digitalis or milkweed) could still send poisonous or harmful substances via their composted remains into food crops grown with that compost. So far it looks like y'all are saying it's not a major issue.

    Bookmark   January 21, 2008 at 7:34PM
Thank you for reporting this comment. Undo
adirondackgardener(Western Maine)

Milkweed gets composted or chopped & worked directly in to the soil in my garden. (There's always some growing in the garden that I leave for the Monarch butterflies.)

Since I get poison ivy just by thinking about it, I wouldn't compost it, much less go near it. I don't know how the heat of the compost would affect the oils which cause the irritation though I think a hot pile would make oils dissipate.

The chemical compunds in the plants that are toxic to us when ingested are generall broken down during the composting process. I've read warnings about Eucalyptus and Walnut, but I'd suggest that unless these were the predominant organic material in your compost, the concentrations of any compound harmful to other plants or you would be miniscule.


    Bookmark   January 21, 2008 at 8:23PM
Thank you for reporting this comment. Undo

I think you are safe to compost any plants. I have used walnut leaves and worse Ollie Ander leaves. Those Oliander lives are very toxic but I found worms eating them when raked in a pile, although they were dried leaves and not green.
The only thing that you should not put into your compost plant wise is diseased plants. Like black moldy tamatoes, ufrasion tamatoe plants, any disease should be in the trash can. Rotating your crops help with this. Also the leaves from a peach three with curly leaf, if you pick these off throw them in the trash can. That is what I would do. BIllC

    Bookmark   January 21, 2008 at 11:37PM
Thank you for reporting this comment. Undo

Like many others about the only plants I will not compost would be Poison Ivy, Oak, and Sumac. I regularly compost Black Walnut leaves and would compost diseased plant tissue if I had any because I have seen much research that says that is okay and none that shows a plant, growing in good, healthy soil, would get that disease from my compost.

    Bookmark   January 22, 2008 at 6:45AM
Thank you for reporting this comment. Undo
maupin(z6 So. IL)

I don't compost spent tomato plants, not out of any concern for toxicity, but because the chance of the pile heating up enough to kill all the pathogens is remote, leaving the capacity to spread plant disease by applying the finnished compost.

    Bookmark   January 22, 2008 at 8:31AM
Thank you for reporting this comment. Undo

If the composting process is thorough, with high enough temperatures achieved and maintained for a sufficient length of time, no plant material is forbidden, neither those with allelopathic properties or those containing disease pathogens. The process will break everything down into its elemental forms, rendering them harmless. A proper composting process is a great equalizer - the end result will be of uniform quality and substance regardless of the quality and composition of the initial ingredients. That is the entire point of composting.

    Bookmark   January 22, 2008 at 8:50AM
Thank you for reporting this comment. Undo

If I'm not sure the compost will get hot enough, I avoid bindweed, especially the roots and seeds, but if I know it'll get hot enough, I'll compost anything.

    Bookmark   January 22, 2008 at 10:26AM
Thank you for reporting this comment. Undo

I'm with BP, only my forbidden plant is horseradish. I've seen dock and dandelion roots survive composting, too, but they're easy to pluck or sift out. But I don't trust horseradish not to take over the world. I let the castoff roots rot in a bucket of water until slimy before throwing them into the heap.

Here is a link that might be useful: my website

    Bookmark   January 24, 2008 at 8:10PM
Thank you for reporting this comment. Undo
gardengal5(z5 IL)

Is it a good idea to add Norway maple seeds to the compost pile? Or will I have trees sprouting in there just like all over my yard and beds??

I have raked up a trash bag full and am wondering if I can just leave it in a corner of my garden or should I just toss it out? There is some hardwood mulch mixed in.

    Bookmark   June 9, 2008 at 5:32PM
Thank you for reporting this comment. Undo

There is some research out there that indicates that it is not the heat of a compost pile that is needed for control of weeds and seeds but the length of time they are composted. Same thing with potentialy diseased plant material, the longer it is composted, not the heat of the compost, is what develops the needed immunities to control these disease pathogens.

    Bookmark   June 10, 2008 at 7:23AM
Thank you for reporting this comment. Undo

Not sure if I would compost materials that had a systemic insecticide/pesticide applied recently such as some of the Bayer products . The label recommends not using these products on fruit bearing plants . If you were using the compost on anything other than edibles then it should not be an obvious problem .
Seems that the time materials spend in a compost would be the most important in mitigating harmful ingredients but again - not sure .

    Bookmark   June 10, 2008 at 7:53AM
Thank you for reporting this comment. Undo
iowa_jade(C 5b H 6)

A whole bag full of Norway maple seeds! Oh Boy! If you have gone to the trouble of bagging them up, I would just let them sit for awhile and bake until the seeds are no longer viable. If plastic bag just punch a few holes in the bag, like with a digging fork and it will turn into mush ready for the compost pile when it was ready.

Do as I say and not as I do. I just raked everything up with the excess grass clippings and dumped it into the compost bin with a nice layer of browns over it. I guess I will see how much they like it in there. I guess it is finding out the hard way, which I am good at.


    Bookmark   June 10, 2008 at 10:25AM
Thank you for reporting this comment. Undo
joepyeweed(5b IL)

I probably wouldn't compost fake or plastic plants...

    Bookmark   June 10, 2008 at 3:18PM
Sign Up to comment
More Discussions
Planting in area covered with "playground" wood chips
I need some advice... I recently had a small playhouse...
Questions about gritty mix
Hi folks, I am a long time gardener but new to the...
hsw (zone 6, Boston area)
Does anyone not like newspaper for weed blocking?
I give advice as a master gardener for my county extension...
Need advice on watering succulents with new soil
I recently began using soil-less soil, as has been...
Miracle-Gro Garden Soil
I was at Home Depot this morning getting a few things...
Sponsored Products
Warm White Bonsai Flower LED Tree
$24.99 | zulily
White & Blue Zoen Pot
$6.99 | zulily
Deer Park Ironworks Starburst Arbor - AR202
$200.86 | Hayneedle
Orchid Bloom Plaid Chenille Throw
$19.99 | zulily
Jaipur Anatolia Sultan Flat Weave Tribal Pattern Wool Handmade Rug - RRC001010-0
$83.00 | Hayneedle
Algreen ErgoGarden Elevated Garden Bed Planting System - 32002
$149.99 | Hayneedle
Jaipur Konstrukt Kelle Solid Pattern Wool/Silk Handloom Rug - RRC217134-0001
Tulip Wreath
Grandin Road
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™