Because small seeds don't germinate well in the presence of many large particles and certain root crops don't form nice roots with chunks of solid stuff in the way.

Because purchased and "free" compost you didn't make yourself often has quite a bit of coarse, undecomposed wood chips in it.

Because if you already have sandy soil that doesn't retain water the last thing you need is large particles holding the structure open even more.

But, if you don't specifically need to do it I agree that its a lot of unnecessary work in many cases. :-)

Compost applied as side dressing for squash, tomatoes, melons, peppers, etc. I don't sift.

Compost applied to be tilled in I don't sift but I do hand-pick out things too large/solid for the tiller to pulverize.

Compost filling a pit below a squash hill or a trench under a row of beans I don't sift (again hand-picking anything I don't want to hit with the tiller at the end of the season).

But when I'm starting seedlings in pots, preparing a lettuce or carrot bed, etc. I sift. :-)

If I ran everything through a shredder before making the piles I probably wouldn't have to sift any of it, but the stuff rots well enough just piled up so I don't.

It's fun.

If using as topdressing for lawns, people don't want acorns, pine cones, small stones, sticks etc etc in their grass.

People like the looks of sifted compost more than un-sifted. I have both and without exception they want the sifted stuff.

It's fun, I like sifting it.

Lloyd

I sift the compost that I put on the lawn for a couple of reasons.

The chunks don't look good on the lawn and they can keep grass from growing through as well.

Also, for some reason, our dog seems to think that any chunks of black or brown that aren't her poop must be food, but she leaves the sifted stuff alone.

I used to be of the opinion that sifting was a waste of time. In many cases it might still be a waste of time, but I've recently learned that unfinished compost inhibits seed germination, especially small seeds.

Large chunks of compost from my compost piles are usually unfinished compost that stuck together. I think that this coming fall will include some time sifting some compost to break it up and give it a chance to finish before springtime.

I will be using unfinished compost between established plants to help prevent germination of weeds.

If I had a sifter like Lloyd's I might like sifting also. I have a 4 board and mesh sifter which resides in the shed while I pretend compost doesn't need sifting. Really it doesn't altho I might be putting it on my lawn if I did sift it. One more job to add to the list. ;-)

Okay, I get it now. You folks are great for pitching in.

I always start seed by winter sowing, for which actual garden soil, not compost, is used. That's why I didn't connect seed starting with compost.

I don't buy compost so don't need to worry about unfinished chunks of wood or whatever. I never imagined that paid-for compost would dare to have clumps in it.

I don't have a dog and the feral cats have not yet developed a taste for chunks of compost.

I don't like grass and refuse to expend time, energy, non-renewable resources or my compost on it; so never connected unsightly lumps and bumps round the green with the need to sift. Heck, I barely stir my lazy and ample posterior to pick up fallen limbs after the wind storms. Little weeny lumps of compost certainly wouldn't be a bother.

Using unfinished compost as a weed deterrent is something I understand, though.

I never thought of sifting as being a pleasurable pass-time. Apparently it's as satisfying as is fluffing and flipping the heaps. For that, and that alone, I would sift.

Thanks for enlightening me! I swear I'll understand it all before I'm too much older.

I only sift my compost if I want to use it for starting seeds. That is because there is no need to have small twigs or bits of leaves etc in the small starting pot. It has nothing to do whatsoever about nutrition. But I want a nice smooth material to work with. Other than that I just use it as is around my plants and in the soil.

Some people need to have "nice" looking compost free of large chunks while others don't. I've not seen any problem with seeds germinating in my unscreened compost or with plants growing in my unscreened compost.
I have had some people visit and wonder what that white stuff on my garden was (egg shells) that thought my planting beds looked "messy" because they had compost and mulches on them with no bare soil exposed to the ravages of the sun, wind, and rain, but many of these people had brick red or bright gold wood chip mulches in some places and that to me is atrocious.

kimmsr, you're my kinda composter and gardener.

I don't like that red mulch, either. What makes it red? Is it spray painted or something? My neighbor bought a huge load of it last year, had it dumped in his driveway. It only sat there a few days but it turned the concrete an ugly orange. Now, a year later, it's still orange.

So what is that stuff?

Karen

I cold compost and it doesn't get turned so in the fall I sift it. I have a large screen with 3/4 inch holes that I use.
jim-6b

I sift because only the core of my compost bin actually composts. The outer layer stays dry and almost intact, as insulation.

It's surprising how many years an orange can last in a compost heap.

"What makes it red? Is it spray painted or something? My neighbor bought a huge load of it last year, had it dumped in his driveway. It only sat there a few days but it turned the concrete an ugly orange. Now, a year later, it's still orange. "

I asked that question of a local tree service that sells mulch...they use iron oxide. I'm not sure all red mulch is colored that way. Iron oxide certainly would stain concrete, though.