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How do I screen my Perlite for small starter pots?

Posted by jimigunne 9A (My Page) on
Sun, Dec 4, 11 at 8:14

I am making up a bunch of seed starter mix for next spring.
I got a good deal on big bags of perlite, however, the particle size is not sorted, it varies from almost powder to around 9MM. I use mostly peat pots that are small, abt 1.5 to 2 in. So when I make my seed starter mix (peat moss, perlite and vermiculite) I have to first screen the perlite. I checked a bag of Jiffy seed starter mix, and the perlite particles were not over about 5 MM. I am making up about 30 gallons of starter mix, so its too time-consuming to just pick out too-large perlite particles.

What I need is a piece of screen or a sieve with a 5MM mesh openings. I have searched the internet, and not found any screen of this specific size. I have found on eBay they are selling a three-piece soil seive set (high-dollar----abt $25.00!). One of the sieves is I believe a #10 mesh, but I don't have a clue what MM size it is.
I thought about using a piece of window screening, but the mesh size is really tiny, like under 1 MM.
Then the other problem is that once I have filtered out all the oversized particles, how can I crush them finer?

Follow-Up Postings:

RE: How do I screen my Perlite for small starter pots?


Mesh size is the number of openings per inch of the mesh; so #10 mesh would be very small openings. To come up with the actual size of the openings, you'd need to know the thickness of the wires that make up the mesh. There are about 25 mm in one inch, so for example if the wire thickness would take up about 5mm, you would need #4 mesh to get 5mm openings. You might be able to find galvanized hardware cloth that would be very close, but coming up with exact 5mm openings will probably not be easy :-)


RE: How do I screen my Perlite for small starter pots?

For my seed starting mix I occasionally need a smaller size vermiculite and use a spice or coffee mill to break it into smaller pieces. Al

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