Weedy compost

I was really pleased with the look of the compost on my heap this spring. It had been composting for about 18 months, smelt sweet, was a rich, dark, crumbly consistancy and I couldn't wait to get it on my beds. I thought I finally cracked this composting lark!

But, everywhere I put it is now covered in lush young weed growth, millions of them. The story is different in the beds I haven't got round to with the compost, so they must have come from out of. I thought that weed seeds were killed in the composting process. What have I done wrong?

 

"covered in lush young weed growth, millions of them"

They are only seedlings though, so will be killed by hoeing (in the main). What the ground gains from the compost outweighs the pain, although I can understand it probably doesn't feel like that right now! You'll thank me in five years time when your soil is a beautiful black colour!

"I thought that weed seeds were killed in the composting process."

You need a hot composting process for that - hot composting will take a few weeks, rather than 18 months. That [usually] means turning the heap regularly, and being careful about what is mixed with what so that you have enough "hot" material - like Nettles, Comfry and a modest amount of grass clippings. Using an [artificial] compost accelerator might help - like Garotta

 

K is right about everything up there (usually is), one thing I may add is: weed seeds don't have to go in the compost in the first place. SOme will end into it whatever you do, ok, but you can be discriminate about the composting material. Never throw mature weeds in the compost, meaning ripe seed heads and roots. These should be burned or sent to the council compost, that is hot enough to become sterile. A heap of grass clippings even a small one will be amazing hot for a few days and can bake the seeds of weeds, but as a rule it's better to play safe and keep the weeds out of the compost.
I have 2 different compost heaps. One for "clean" compost and one for weeds. The weed compost I use in places where weeds wil be asily dealt with or not matter. It is yet another approach.

 

"I have 2 different compost heaps. One for "clean" compost and one for weeds"

That's a good idea, I like that.

We had a huge amount of Groundsel earlier i the year. It was just coming into flower and I was chuffed to have caught it in time.. I spent hours pulling it up, and hoeing it off. But I was lazy and piled it up at the side of the beds, rather than carting it to the compost heap. I came back a week later and the whole lot was in seed - the piles and the hoed-off-bits. So I've got the blighter for the next 7 years at least :(

(I've since distributed 1-ton-bags (the sort that builder's sand comes in) around the garden so that I can drag one to wherever I am working, and at least the weeds are contained, even if I'm too lazy to get them off the plot.

 

I have four big big plastic pots, the kind used for baby trees in nurseries, black plastic with handles, placed at strategical corners of the garden. Not decorative, but practical, for chucking weeds and things in.

 

Thanks for your advice. It is obvious that I still have much to learn about composting. I didn't know that it was good to add nettles. I thought they would be classed as a 'nasty' weed, along with goose grass and brambles, so I don't add them. It also never occured to me not to put mature weeds in. Sounds logical now it has been mentioned though. I do add some grass clippings and cardboard and have an old carpet on top, but to be honest I neither have the time or energy to turn my tip. I did try a tumbler once, but it made a disgusting, fly filled mess.

 

I put all the good stuff in my compost bin and all the other stuff in the council green wheelie bin.:o:p 02

 

If one is not sure about weeds, or has no time to keep things sorted and take care of two different heaps that is certainly the best solution.

Nettles are enourmously useful (and tasty) plants, but they ARE weeds, and the same rules apply to them as for other weeds: they are welcome in the compost as long as no roots or ripe seeds is included.

 

After reading all this, I'm scared to go look in my compost bin. I bet I have all sorts of nast weeds waiting to grow again. what if I was to big the unused bit of my veg. plot and bury the compost .....welll.....sort of bury it, not too deep. Would that not improve the soil condition and at the same time the weeds might not come thru.

 

You could put it at the bottom of the "spit" as you dig the pot. I reckon that would be fine, and the seeds are a long way down, but the seeds are likely to be efficacious for 7 years or more, so those that come to the surface are still likely to grow.

(A plough works a bit like this - there is a little mini plough share at the top, and then the big plough share underneath. The little one scraps off the top inch, or so, and it drops straight into the bottom of the previous furrow - and the stuff turned by the big plough share immediately buries it! )

Personally I don't worry about it. I have to weed the veg patch anyway, anything that comes up as a seedling is pretty weedy (Sorry!) and probably won't survive the first hoeing. Of course it WOULD be better to keep such stuff out of the compost heap, but I don't have the time for such niceties. Maybe when I retire ...