Hi Bill!  Thank you for your dedication to composting!

We'll need more clues to help you identify the roots plaguing your compost pile.   Can you provide answers to these questions?

• This looks like a cold-composting system (i.e.:  not a "hot" system in a bin that heats up the contents to kill seeds/weeds) -- are there any containment elements here?  (A base...sides...top?)  Or are you doing cold composting by layering plant refuse on the ground (without containment)?
• Do you have trees nearby?  (Roots aren't easy to id on their own, but these look fibrous....I don't see a tap root in this photo example.)  If you have a layered cold composting system:  nearby trees may be delighted to extend their roots to this nutrious source....
• What happens when you try to pull up/remove these roots?  Do they come up entirely (lending support to your hay theory)  or are they connected to some larger roots (like tree roots... :-)?
• Can you send more photos showing the larger area?  (I.e.: what surrounds this compost pile.)

If the seeds came from the hay you added (a good theory if the hay contained seeds...):  you should be able to pull the roots/weeds out and with persistence, win the battle.  (Provided you don't add more hay with seeds! :-)

If the roots are coming from nearby trees or other plants:  you may need to switch to a compost solution that's contained (at least at the ground level).  

Hot composting, of course, would kill seeds and disease...but it takes more effort and often some expense (to purchase or build the containment system).

Sorry  I can't offer more from this initial info.  Kindly send more photos/information and we'll do our best to help you out here.

- Robilee Smith,  UVM Master Composter (and Master Gardener)

Thank you for the additional photos and information, Bill!  I'm so glad you found our Helpline/Ask Extension service!

Based upon what you've shared, I'm guessing that the "old mulch hay" that you added to your cold compost pile (I believe I can see some of this in the photos :-) is the likely culprit.  One clue is that wheat/rye/oats like to focus on root-building at this time of the year.

Hay is comprised of harvested grass crops that contain seed.  For cold composting: it's worth seeking out straw -- straw is hay that's been threshed so that most of the seeds have been removed. 

Of course: that's "seeds already in the compost" for you now.....just a tip to consider for the future.

I like the hyphae theory, too, but I don't see any signs of fungi/mushrooms in the photos you've sent.  Perhaps you've found some?

So:  what can you do about the roots in your compost pile?

Well, I'm glad to hear that the roots pull up easily!  :-)

I think there's a bit of a silver lining here for you:  the roots are probably adding good nutrients to your compost pile.  We receive questions from gardeners who want to enrich their soil by growing cover crops to add nitrogen and other nutrients to their garden soil.  If the roots stem from hay seeds:  then you've introduced a form of cover crop to your compost pile that's probably adding nitrogen.  If they are hyphae: then you've added welcome mycorrhizae (fungal roots).  

It's possible that the "hay seeds" are from an annual grass that will be killed by winter frosts.   If not:  then I recommend that you turn the compost as much as you can manage.  I.e.:  breaking  up and exposing the roots will help to kill and break them down and they will then become beneficial additions to your resultant compost.  As with all unwelcome weeds:  the sooner you start, the easier it is.  So if you have the time & energy:  I'd start now since it will be harder to do manually in the Spring if the plants sprout and grow stronger.  But if you have to wait until the spring: start as early as you can easily turn the compost.  Perhaps you'll be lucky and find "no more roots -- it was an annual! Yay!"  It's healthy to turn over your compost pile periodically regardless and you can do this with a pitchfork, a shovel, or with a tool designed specifically to help mix and aerate compost. 

I'm attaching an image of the type of compost aerator I use, just FYI.  I have one hanging on the back of my garage right next to my compost bin.  This type works well if your compost is several feet deep.  (You plunge it in and the "wings" then open up as you pull it back up.)

One key tip here:  I wouldn't spread this compost over my gardens with these living roots ready to sprout unless I was prepared to do extra weeding.   If you are desperate, next season, to use this compost:  you could try a rapid form of hot-composting to kill the roots.  If it were me:  I'd spread some of the compost out in a thin layer between sheets of black plastic in full sun and let it bake for at least a week.  (In hot composting, you strive to get the compost over 133 degrees for a minimum of three days...but a thin layer won't hold the temperature overnight....so aim for a longer period.)

To answer your question about adding sides to your cold compost pile:  it's not necessary if you aren't adding food scraps or other substances that attract animals.  It's vital for a hot composting system, of course, but your layering system works just fine for cold composting.  

Finally: we normally have the ability to invite you to drop off or send us samples of plant material to analyze in our labs at UVM Extension;  alas: this service has been closed since the start of the pandemic and since this year's home gardening season is drawing to a close, I imagine the earliest we could offer to help with diagnoses in the lab will be next spring.  But you do have the means to gain more clues if you are curious:  you could allow some roots to grow so that we could see what comes up....  (If it were me:  I might move some of the compost with roots into a pot to contain my experiment.)   

If you haven't yet checked out the composting resources listed on our UVM Master Gardener/Master Composter site, I invite you to do so:

https://www.uvm.edu/extension/mastergardener/gardening-resources     (Click on "Composting")

We also offer the VT Master Composter course each fall in case you might be interested.  The 2022 class is full, but you can be placed on a waitlist for 2023.  Link: https://www.uvm.edu/extension/mastergardener/master-composter-program

I hope this helps, Bill!   

THANK YOU for over thirty years of composting your garden refuse in Vermont!

- Robilee

Thanks so much Robilee.  Your feedback is very helpful.  Bill

Sent from my iPad