How long do you need to leave weeds in a garbage bag in the sun till you can add them to compost?

I heard that if you do this the seeds won't germinate when you add the compost into your garden

Asked by Belinda Nikolov

1 answer

  • Belinda,
    Leaving weeds in a black garbage bag in the sun is a good way to reduce seed viability. Remember it is the seed viability that you are trying to influence is only in the seeding parts of the plant i.e. if you separate the seeding parts of the plant from the rest you will have a significantly reduced volume. In reading "Time and Temperature Requirements for Weed Seed Thermal Death" they state that over 50 degrees does the job on everything. You can also boil a kettle and pour hot water on your weed seeds.
    You are going to need good sun exposure to get the temperatures inside the garbage bag over 50 degrees. If the temperatures are less than this you will still have impacts on viability but not complete thermal death. If your compost is thermophilic(hot) you will also significantly reduce seed viability. Note that each weed seed has different characteristics.

    Answered by David Winterton
    Green Beret
    Rating: 0

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