Mistake in composting- soil is infested with weed seeds

Mistral001

About six years ago I tried to compost a heap of large weeds, mostly nettles, with disastrous consequences. There must not have been enough heat produced to kill the seeds as the next year when I used that compose in window boxes you could count the number of nettles growing in among the petunias in their hundreds.


I have since improved my composting techniques and no nettles or any large weeds go in the compost bin and I make sure that heat builds up. But five or six years on from putting those nettles into the compost I still get dozens of nettles growing in my window boxes as I reuse the soil every year.


I do not want to throw the soil out and have sterilised some of it by steaming of it but I find that very slow and uses too much electricity. Has anybody got any other ideas?

SailorSam

To late now but i normally chop the heads off any weeds and put them in the grass bin, let the Council compost them. The bottom half of any weeds go in my compost bin.

Mojisola

Mistral001 wrote: »

I do not want to throw the soil out and have sterilised some of it by steaming of it but I find that very slow and uses too much electricity. Has anybody got any other ideas?

Are they massive window boxes - would it be very expensive to replace the soil because that's the easiest way to solve the problem.

Otherwise - could you spread the soil out over some plastic in the garden so that it's just a few centimetres thick, moisten and let the weed seeds germinate, rake it around so that the seedlings die off, let more seeds germinate and repeat until the weed load is reduced.

keelyjrs

Keep the nettles!! Great for tea and soup plus soaked in water for a couple of weeks it'll give you a lovely black stinky but super effective natural pesticide

unrecordings

I've just buried my first and only batch of nettle tea (for the garden not for drinking) - i decided that no matter how beneficial it might be i didn't like my greenhouse stinking like the public toilets on Bridlington seafront in the long hot summer of '76

(cue a chorus of 'you idiot - why did you put it in the greenhouse')

wellused

keelyjrs wrote: »

Keep the nettles!! Great for tea and soup plus soaked in water for a couple of weeks it'll give you a lovely black stinky but super effective natural pesticide

Does it work as a pesticide? I did wonder as I made some to feed my brassicas and since using it I seem to be getting very few caterpillars, the plants are growing well too so it seems to be a win win situation.:T

Davesnave

Mistral001 wrote: »

About six years ago I tried to compost a heap of large weeds.....

.....five or six years on from putting those nettles into the compost I still get dozens of nettles growing in my window boxes as I reuse the soil every year.

....I do not want to throw the soil out

Let me get this right: you have six year old soil in your window boxes and you want to keep using it?

I know this is MSE, but it really is time to change your compost! Hopefully, you wouldn't leave oil in your car's sump that long, so why would you expect your window boxes to keep on giving you service for a similar length of time?

Unlike the oil, you have the option of re-using the compost elsewhere, mixed with a much larger quantity of other material. However, as a restricted growing medium, it is now largely exhausted and possibly full of potential pathological problems for whatever you grow.

Even my chickens get a change of soil every year.....:)

Davesnave

unrecordings wrote: »

I've just buried my first and only batch of nettle tea (for the garden not for drinking) - i decided that no matter how beneficial it might be i didn't like my greenhouse stinking like the public toilets on Bridlington seafront in the long hot summer of '76

(cue a chorus of 'you idiot - why did you put it in the greenhouse')

If you contain it for a year or so in a suitable sealed receptacle, most of the smell goes.

Lavendyr

SailorSam wrote: »

To late now but i normally chop the heads off any weeds and put them in the grass bin, let the Council compost them. The bottom half of any weeds go in my compost bin.

Why do you do it that way round out of interest? I would have thought that it would be better to put the roots in the council waste bin and the leaves in your compost bin?