There is a lot of research out there today that says it is not the heat from composting that kills the "weed" seeds but just the process itself. One report I saw said just as many "weed" seeds were killed in a cold compost pile as a hot compost pile, mostly because they germinated, could not get any light to grow, and died.
If you harvest those "weeds" at blossom stage, when they are at the nutritional peak, they will have no seeds to be concerned about, anyway.

Hmmm... good points. Thanks, kimmsr. They're typically seedlings when I get them right now, so I guess I'm more worried about zombieweeds. They'd also be readily dispatched from the process you describe.

In retrospect, so many of our weeds are airborne and seemingly sprout from nowhere, I guess my worries are completely misdirected. Thanks again.

I'm doing an experiment using weeds .
I have a compost pile going with just summer weeds ,
paper and cardboard , cow manure , yard trimmings and some wood chips .
In just ten days the pile is huge !
It shrinks quickly . I turned it once .
I'll keep adding to it for another month .
I have some of the most stubborn weeds on the earth
so it will be interesting to see if they reappear months from now
when I use the compost in garden beds .
I'm not gonna let the weeds beat me ! I will win !

So it's really okay to put weeds in the compost? I have so many weeds that I hand-pull and put out for pick-up day. But if they can go in the compost without overtaking it, that would be great. I'm a little nervous about this - "Do not spread the compost on the weeds to make them ranker." - Shakespeare

You can put "weeds" in your compost. Just try to not put the roots and seeds of those "weeds" that are seriously invasive in your garden in there, or be very careful with those that can root from stem cuttings, chickweed, purslane, etc.
I think the people that tell you to never, ever put "weeds" in your compost need things set in rigid terms because they cannot figure out which plants might have seeds or might be invasive.

Bindweed or wild/beach morning glory, thistles, and comfrey roots, flowers and seeds, are some things I keep out of the compost pile. But most weeds go on the pile, well-covered. As Kimmsr said temperature isn't so important. A lukewarm or even cold compost pile is a good place for weed seeds to sprout, but the moisture and lack of light also make it a good place for those sprouted seeds to rot.

I'll put weeds in the compost until it starts looking like it's becoming nothing but weeds. Then I'll step back and say to myself- "Methinks thou dost process too much"
-Wilbur Shakespeare.

tj

I've got a lot of really invasive weeds - creeping charlie being the only one that I can identify. Some of them are huge - I think they're triffids! How about if I put them in black plastic bags and let them "cook" in the heat for a couple of weeks? A month? I hate to put anything more in the landfill than is absolutely necessary. But I have really good compost and don't want to mess it up.

(BTY, Wilbur, just to be a stickler, it's actually "The lady doth protest too much, methinks," but thanks for the quote anyway!)

If the "weeds" are not those that can root from the stems, things such as Chickweed, Purslane, etc. and do not have seeds or roots, even if they are in blossom, they will simply add the nutrients they have to your compost and not grow more "weeds". Even if you left the roots on the plants and buried them deeply those plants will die and not grow. That said there are things that I would not compost, which include Quack Grass or Johnston Grass rhizomes.
Many times, however, the "weeds" get tossed onto the lawn and mulch mowed in rather then expending the time and energy needed to haul them to the compost pile.

I throw weeds into the compost bin all the time, and they seem to break down fine. The seeds typically sprout and die when I turn the pile, so that takes care of the seeds. The only thing I have a problem with is pumpkin seeds. They have a tendency to go dormant in the pile and show up when it is finishing, so basically I just let it sit for awhile before I use it and chop up any seeds that sprout. Most of them never make it through the pile, but pumpkin seeds are tenaciously. This Halloween I am going to take extra care to keep them out of the pile. And I agree with paulns, morning glory seed should never go in the pile. Someone planted them a few years ago where my garden is now, the damn seedlings are still showing up. Word of advice, if you plant morning glories, you had better dead head the thing and keep the seeds from dropping, cause they will never go away.

playsinthedirt20- ...it's actually "The lady doth protest too much, methinks,"...

Thank you for that, but...my compost pile is no lady ;-) Beautiful, yes, but a bit soiled and sullied and eats like a horse.

tj

I have a lot of ragwort to get rid of, and from experience if you pull it up when it's in flower, it will still manage to go to seed, so I keep a big bucket of water next to the compost heap and plunge all the ragwort head-first into it. Then I cut the stems in half and stack the root ends for a few weeks in the sun to kill them off before composting them. I leave the flower ends in the water for about a week until it starts to stink and then bury them in the compost under a load of donkey poop.

Tomatoes and acorns are the only things I remember actually sprouting while composting. Easy to remove, but still, I'd rather keep them out than have them germinate in my beds after spreading the compost.

I don't add mature tomatoes to my compost, but I do get a lot of acorns with my neighbor's oak leaves. If I could just keep my husband from throwing those tomatoes into the compost.

I do compost weeds, but avoid putting in mature blossoms of some things. Verbena bonariensis sprouted everywhere this year, becoming positively invasive. Of course no way to know what seeded directly in beds and what might have sprouted from compost. I'm trying hard to get rid of it now, but I suspect I'm going to find them for years.

Karen

My first line of defense with weeds is to throw them over the fence to the chickens. That way, the weed seeds are picked out, the chickens get more lots of greens, and the eggs have orange yolks.

I too send everything thru the chickens first.
2 or 3 times a year I dig out the chicken pen and shovel everything into compost bin #1. After about a month I turn bin #1 over into bin #2 - wait 2 more weeks and it's ready to go into the garden. I then repeat the process until it snows.
I still have a problem with the bindweed though. It doesn't survive the chickens but there is just so much of it I inevitably miss some somewhere.