LECA Comparison Study
 

Over on Facebook, someone suggested that there needs to be an updated comparison of available brands of LECA, similar to the one I did about 20 years ago.

I volunteered to do that if folks will send me samples to test. Here's how this is going to work: I already have Hydroton, so if you have another brand of LECA and are willing:

1) Send me a PM with the brand. If I do not have that one in my array of materials, I will share my shipping address.

2) Get a small, flat rate box from the USPS ($7.90 postage), fill it with NEW, UNWASHED material, and send it to me. (To compensate you for that expense, I'll send you a coupon code that will give you $7.90 off the price of a bottle of KelpMax.)

3) Once I have received the samples, I'll run a variety of tests and will publish my results.

Right off the top, I thought I'd do the following:

> TDS of soak water - will tell us how important precleaning is.
> Bulk Density - relates to stability,
> Wicking ability
> Free air space
> Absorption

Any other ideas?

I was thnking about cleanliness before use.
Related with TDS of soak water but, if my interpretation is correct, I mean insoluble contents right after opening a new package (dust, etc).

Other than a visual assessment, how would you evaluate that?

Besides - and this relates to the TDS too - they all need to be thoroughly cleaned before use anyway.

If you own a precision scale, a ratio between both weights, LECA and dust. Or by package.

Yes, I see what you mean but I think you're doing it by the orchid growing point of view (TDS and so).
But I'm thinking about the dust one must handle everytime you have to manipulate LECA. Apart from the complete mess if you don't take some precautions, there's also air/lung contamination.

Well, I'm no science guy, but I think that particular issue of dust would be pretty impossible for Ray to do with the type of testing he's setting up. He's asking for folks to send an unwashed small USPS priority box of unwashed LECA to him for the experiments.

If you've ever opened a big bag of LECA, you know there's going to be more dust at the bottom of the bag, less in the middle, and even less at the top. So he would have to have a whole bag of each brand in order to come anywhere close to accuracy on dust content. Then depending on the size of the bag, 5#, 10#, 50#, where the individual has taken that LECA to send him for the test. Take it from the top? The middle? The bottom?

Yes, hopefully it's all from a growing orchids point of view...but I think the amount of dust is not one of the main factors. Those who are picky about what goes into the air or one's lungs should be wearing a dust mask to begin with. Those who aren't picky... well, breathe away. Doing a TDS of the material provided after washing is likely about all that can be done, with this particular venue/experiment/whatever ya call it. And if I'm full of it, I know someone with a more scientific bent will be happy to correct me.

For me, knowing the wicking and absorption ability is more of interest to me than anything else.

I'm trying to track down a bag of RK2 filter media, which is the small 4mm-8mm size, but nobody seems to stock it. I'll probably be a little late to the dance, but hopefully I can get a bag in the near future to submit a sample for testing.

Any time, John.

Even if I get other samples sooner, I can always add data for another product later, although wicking will change with different RH, so I'd like to do them more or less simulataneously, if possible.

As a general comment, what I'm looking for is data that can guide us to better growing, not cleaner handling.

yes you need to include a salt test. That means licking each sample and rating its saltiness.

Also an actual grow test would be most conclusive compared to other media but I can see this is just a bit of fun and games with no real scientific purpose.

Whatever floats your boat Ray

🙄

It's more than just "fun and games". 20 years ago or so I did some similar testing, in which I compared the bulk density, open volume and absorption capacity of a handful of products - all of which affect their performance. Someone recently suggested an update, so I volunteered to do so.