What Is a Riddle Sieve? Screening Soil and Compost
A riddle sieve is a round garden sieve with a wire mesh base that sifts soil or compost. Fine material falls through while sticks plus chunks stay on top. None of the sources names the riddle, so the facts below come from their compost screening notes.
The short answer
A riddle sieve screens compost or soil so only fine material reaches your pots plus beds. UF IFAS advises a 1/2 inch screen to remove material that has not yet broken down. NC State notes a simple screen can be made with half inch hardware cloth on a wood frame. Return large pieces to the pile.
When is compost ready to sift?
Colorado State notes finished compost shrinks by about half, loses the look of its materials plus smells earthy. That usually takes three to nine months.
| Item | Detail | Source |
|---|---|---|
| Mesh size | 1/2 inch | UF IFAS plus NC State |
| Frame | Wood with hardware cloth | NC State |
| Time to finish | Three to nine months | Colorado State |
Source: UF IFAS, NC State plus Colorado State.
Why sift compost?
UF IFAS notes only fully decomposed compost should go into a potting mix. Raw compost may stress plants, causing yellowing or stalled growth.
How to: step by step
- Set the sieve over a wheelbarrow.
- Add a few shovels of compost.
- Rub it over the mesh with a gloved hand.
- Lift the sieve to see the sifted compost.
- Put large pieces back on the pile.
Troubleshooting
Clogged mesh: compost too wet. Dry it a little first.
Lots left on top: compost not finished. Return it to the pile.
Sour smell: too wet or low air. NC State advises turning the pile.
Read fertilizer plus compost for growing outdoors, peat moss for cannabis plus cover crops for cannabis. Kind Seed Co also stocks cannabis seeds.
Sources
- Making compost, Colorado State University Extension
- Extension Gardener Handbook, chapter 2: Composting, NC State Extension
- How to use compost, UF/IFAS Extension Sarasota County
- Extension Gardener Handbook, appendix D: garden tools, NC State Extension
FAQ
What mesh size should a riddle sieve have?
UF IFAS advises a 1/2 inch screen for compost. NC State notes half inch hardware cloth on a wood frame works.
How do I know compost is finished?
Colorado State notes it shrinks by about half, loses the look of its materials plus smells earthy.
Can I use unfinished compost as mulch?
Yes. UF IFAS notes finished or unfinished compost can go on the soil 3 to 4 inches thick as a mulch.
What do I do with pieces left on the sieve?
NC State notes pieces too large to pass through may go back into the compost pile.
Can sifted compost make compost tea?
UF IFAS describes soaking a burlap bag of finished compost in water for an hour, then using the liquid to water plants.
