Compost, how to use it & when to sieve it

If you haven’t been following our adventure with composting over the past few years you won’t know that we started off with the big, standard type compost pile at the back of the garden (build from odds and ends of wood) and are now using a swanky hotbin composter.

Our old home made compost bin

But fear not, you can catch up on the adventure with the post below and come back for the latest chapter if you like:

The hotbin composter

We are very lucky that we have the fancy hotbin composter that produces compost very quickly, unlucky however that I sometimes find I have compost ready for use but I don’t actually need it. This happened over the winter when I had to empty the compost bin as it was full and I obviously still needed a way to manage our waste. So I emptied the bin and stored everything in black rubble sacks ready for when I would need it.

My custom built filtering sieve and bags of compost ready to go

Now here is a useful thing to know for any new composter types out there. Fresh garden compost can be quite rough and bulky, don’t panic though, just cause it doesn’t look like the super fine stuff you are used to buying from the store. The reason the stuff you buy is super fine is because it has been sieved.

Here’s the skinny… you know when Jim on Beechgrove Garden or Monty on Gardener’s World tells us to add organic matter to the soil to make it better? Well this is what they mean, the rough and ready compost. It adds bulk and texture and air etc to the soil. Stops the soil being too fine and getting compacted and if you have sandy or clay soil helps to change the composition. The bigger bits keep on breaking down providing nutrition too. All in all this is awesome. You will also have heard Jim and Monty talk about mulch? Yeah well this compost is exactly that, mulch, so you can even spread it over the soil around plants to feed the soil and suppress weeds. Money saver!

Now what if you are potting up plants or little seedlings? Well then this compost is a bit rough for this, so you would sieve or filter it to get rid of any larger bits and pieces and leave you with the finer stuff. This will be much more recognisable as the stuff you would buy (which you’ll probably see as labelled multi purpose).

Fine soil after sieving

So, how does this all work?

To do this though, you need the compost to be relatively dry otherwise it’s a bit on the sticky side and it clogs up the sieve.

Here was our problem, the compost I had been storing was still quite damp. I had hoped for a few sunny days where I could spread it out on a tarp in the garden and let it dry in the sun, but alas, we’ve had rain for months. So it never happened. This weekend though we finally got a chance, so hurrah.

This also provided Kate with a chance to put her DIY skills to the test yet again to make my life easier. You see, I have a standard, bucket sized, garden sieve, which works great, but…. would take forever to sieve a few rubble bags worth of compost. Also it’s very fine, suitable for making potting compost but it takes a very long time to sieve out from brand new chunky stuff.

I need something which a much bigger mesh size, an in betweener if you like. Also bigger would be great given the amount of compost I have to get through.

Kate did a fantastic job and built me my very own extra large garden sieve just for my compost. Just some leftover bits of wood and some fine chicken wire.

between my little bucket sieve and my fabulous big DIY one.

We didn’t record the making of this as it’s dead easy but if you want some instructions fear not, someone else has done an excellent job of this.

So speaking about fresh compost being a bit lumpy, you can see from the pic here what I mean. You sometimes get bits of twig or whatever left over that haven’t quite finished breaking down. It’s no biggie, you just throw those back in and they finish their job. Having a big filtering system does make this easier though. The action of the compost lumpy bits running across the sieve help break down lumps which are just stuck together and separate this from actual large pieces which are not ready.

Fresh compost straight from the bin

So how does the whole sieve thing work? Well, to be honest, it’s all very scientific and complicated, I’m not sure you’d understand. You need to add your fresh compost to the sieve and ………


I usually do this over a great big tarp, then shovel it from there to wherever it needs to be but I can also put the sieve straight onto the frame of my raised beds if I want some finer soil for in there.

using a tarp and sieve on top of the raised bed to filter compost.

And there you have it, lots of lovely mulch, compost for the raised beds, potting on etc. The world is your compost of choice.



  1. Thanks for your post! I have been wondering if my lumpy compost was ‘wrong’, but it looks just like yours. Now I will go and read everything you have posted!

  2. Hey Jen,
    oh compost!!!!!
    This was maybe one of my biggest learning curves. I don’t know if it’s useful but here is the playlist of videos we’ve made over the past few years as I’ve battled to understand it:

    Your compost may be exactly as it’s meant to be 🙂 it all depends on the type of compost. There’s way more science to this than I know about, so I’ll tell you what I know and let you go off on your own research adventure after, but… the compost we buy in the stores isn’t anything like real compost. Instead, it’s a “produced” version made shiny for shops. it’s filtered and dried and doesn’t actually do your garden much good at all. Probably because they make this with pots and container gardening in mind.

    Real compost, when we make it ourselves, has way more of the good stuff, the bacteria, the organisms, the minerals, the organic matter etc, the stuff that is literally the lifeblood of our soil, hence why we add it. There is also a difference in the amount of something called humus. This is the dark, organic material created in soil when plant and animal matter decays. When plants drop leaves, twigs, and other material to the ground, it piles up, called leaf litter. When animals die, their remains add to the litter. Over time, all this litter decomposes. This means it decays, or breaks down, into its most basic chemical elements which are important nutrients for the soil and organisms that depend on soil for life, like our plants. The thick brown or black lumpy material left after most of the organic stuff has decomposed is called humus and when we add this to our beds etc, the worms help mix it through the soil.

    In shop bought compost, an awful lot of this is actually sieved out, so make the fine, dry compost that can be stored and sold.

    Now I mentioned different compost having different amounts… well things like worm cast (vermicast) if you have a wormery or compost from a sealed hot compost bin, these are really, really humus-rich, hence why they tend to be wetter and lumpy. But, if we want soil for pots, we might want to sieve this stuff so that it is finer, if we are using it for seedlings, then we want it to be even finer again – the benefit of this is that a lot of the nutrient-rich humus is sieved out – because we don’t want overly rich soil for seedlings.

    So, how you use your compost, and how lumpy and wet it is, is all-important in how you treat it and use it 🙂 so be proud of your lumpy compost!!! Your garden will love it 🙂

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