Napa 8822
- dustin0352
- Posts: 1303
- Joined: Sat Apr 26, 2008 11:40 am
- Location: East Coast Florida
Ha Ha the fith wheel just got himself some Napa 8822. Had to drive 43 miles to get it, and when I asked for Napa part 8822 they all looked at me like "what the heck is he talking about". Then Billy Bob in the back said "hey ya'll he talkin bout that der kitty litter" lol. Any who got it and love it!! Not quite the same as shultz aquatic soil but still a great product. Thanks for advertizing it guys!!
I've been following this thread with interest (since I started it!), and decided to to do a little experiment, to see how much water each mix would absorb.
I put two cups of mix in new 4" pots, with fiberglass screening to block the drainage holes, then added one cup of water to each. After 10 minutes, I measured how much water had flowed through:
I did my best to pour the water evenly, so all of the mix would be saturated. Except for the pure Perlite, this was easy, since the pots got flooded before I could add all the water.
Results....
Perlite: less than 1/4 cup
1/2 Perlite and 1/2 Scott's Premium Potting Soil: less than 1/4 cup
Pure (previously washed, but dried for several weeks) Napa 8822: slightly more than 1/2 cup
1/2 Napa 8822 and 1/2 Scott's: a bit less than 1/2 cup.
I know this isn't terribly scientific, but I draw two conclusions:
1. Soil amendments have a huge effect on how much water is retained (duh!)
2. Perlite is much more absorbent than Napa 8822 (sorry ian!).
In fact, the perlite absorbed so much water and expanded, overflowing the pot:
A good followup would be to see how quickly each of the mixes loses the moisture, but I'm not quite up to that
-R
I put two cups of mix in new 4" pots, with fiberglass screening to block the drainage holes, then added one cup of water to each. After 10 minutes, I measured how much water had flowed through:
I did my best to pour the water evenly, so all of the mix would be saturated. Except for the pure Perlite, this was easy, since the pots got flooded before I could add all the water.
Results....
Perlite: less than 1/4 cup
1/2 Perlite and 1/2 Scott's Premium Potting Soil: less than 1/4 cup
Pure (previously washed, but dried for several weeks) Napa 8822: slightly more than 1/2 cup
1/2 Napa 8822 and 1/2 Scott's: a bit less than 1/2 cup.
I know this isn't terribly scientific, but I draw two conclusions:
1. Soil amendments have a huge effect on how much water is retained (duh!)
2. Perlite is much more absorbent than Napa 8822 (sorry ian!).
In fact, the perlite absorbed so much water and expanded, overflowing the pot:
A good followup would be to see how quickly each of the mixes loses the moisture, but I'm not quite up to that
-R
Last edited by lancer99 on Mon Jun 29, 2009 1:23 pm, edited 1 time in total.
That's a little too unscientific for me..."dry" is pretty subjectiveswords wrote: Lancer all you gotta do is time how many days each pot takes to dry out - if you haven't dumped them out already.
A better way would be to weight the pots before and after saturation, then see how long it takes for them to return to their original weight. Unfortunately I don't have a scale that's sensitive enough.
-R
Flushed with excitemen, I ran (Usain Bolt has nothing on me!) to do my own experiment.
So I don't have any perlite. I checked the manufacturers figures as well as some published papers and perlite holds between 25% and 50% water depending on the grade, so slightly less than 1 cup of water in 2 cups of perlite is about right. Some companies referenced mixes containing a variety of grades including fines which retain more than 50% water by volume. In experiments, mixes of perlite and typical peat-based soils held a similar amount of water to straight perlite. Intriguing but not relevant to me.
Then I loaded up my cat litter, poured on the water and waited. Nothing. I actually used three cups of water in six cups of litter because that was the size of my cup. It took the lot. I added a fourth cup and got a couple of drips. So it sounds like my cat litter is not quite the same as your NAPA #8822. In fact the cat litter seems to hold more than twice as much water? Anyone else out there with some "stuff" they can test?
Another trick you might like to try is to leave it for half an hour and then add more water. With the cat litter, and presumably the NAPA, it will absorb even more water (probably shouldn't use a clay pot for this one!). This is really the main reason I like it, because it doesn't immediately become saturated when it is watered, but stores away the water and retains air pockets. The actual amount of water retained by the soil can always be adjusted by varying the quantities of soil with either perlite or cat litter.
So I don't have any perlite. I checked the manufacturers figures as well as some published papers and perlite holds between 25% and 50% water depending on the grade, so slightly less than 1 cup of water in 2 cups of perlite is about right. Some companies referenced mixes containing a variety of grades including fines which retain more than 50% water by volume. In experiments, mixes of perlite and typical peat-based soils held a similar amount of water to straight perlite. Intriguing but not relevant to me.
Then I loaded up my cat litter, poured on the water and waited. Nothing. I actually used three cups of water in six cups of litter because that was the size of my cup. It took the lot. I added a fourth cup and got a couple of drips. So it sounds like my cat litter is not quite the same as your NAPA #8822. In fact the cat litter seems to hold more than twice as much water? Anyone else out there with some "stuff" they can test?
Another trick you might like to try is to leave it for half an hour and then add more water. With the cat litter, and presumably the NAPA, it will absorb even more water (probably shouldn't use a clay pot for this one!). This is really the main reason I like it, because it doesn't immediately become saturated when it is watered, but stores away the water and retains air pockets. The actual amount of water retained by the soil can always be adjusted by varying the quantities of soil with either perlite or cat litter.
--ian
Bog-standard perlite, from pennperlite.com.....
Since perlite can't absorb any water (sorry, I misspoke above), but rather aDsorbs, I'm guessing the water that it holds onto increases the volume. And that increase is more-or-less consistent with the volume of the 3/4 cup of water that it retained.
What I found most interesting is that the topsoil had a minimal effect on how much water was retained...I would have expected more.
Now I really want to do some more tests to see how the various mixes dry out!
-R
Edit: Was writing when you posted, Ian! So two cups of Napa absorbed 1/2 cup of water, but six cups of kitty litter absorbed three cups of water. If my math is right, that's twice as much!
And I did (almost) try what you suggested. After 20 minutes, I added another cup of water (not easy with the perlite!)...and each sample produced just slightly under one cup of water. That tells me they were all saturated after the first test. (Which makes sense for the perlite.)
-R
Since perlite can't absorb any water (sorry, I misspoke above), but rather aDsorbs, I'm guessing the water that it holds onto increases the volume. And that increase is more-or-less consistent with the volume of the 3/4 cup of water that it retained.
What I found most interesting is that the topsoil had a minimal effect on how much water was retained...I would have expected more.
Now I really want to do some more tests to see how the various mixes dry out!
-R
Edit: Was writing when you posted, Ian! So two cups of Napa absorbed 1/2 cup of water, but six cups of kitty litter absorbed three cups of water. If my math is right, that's twice as much!
And I did (almost) try what you suggested. After 20 minutes, I added another cup of water (not easy with the perlite!)...and each sample produced just slightly under one cup of water. That tells me they were all saturated after the first test. (Which makes sense for the perlite.)
-R
Last edited by lancer99 on Mon Jun 29, 2009 3:36 pm, edited 1 time in total.
Testing peat-based potting soils for water retention is a nightmare. Baked dry, they will retain nothing, then easily soak up a cup of water if you leave it long enough. If the soil includes wetting agents, water crystals, etc, it could double the amount of water it might hold. Still, you might want to test your soil with nothing added.
The next step in the testing is to see how much more water you can add with the hole blocked. This is a measure of how much air was in the soil after it had been watered.
The next step in the testing is to see how much more water you can add with the hole blocked. This is a measure of how much air was in the soil after it had been watered.
--ian
I wasn't really interested in testing the potting soil, but rather the Napa and perlite. The Scott's Premium Potting Soil (no ingredients listed, of course!) seems to have a minimum of peat, and is in fact quite dense...which is why I was surprised that it didn't have more of an effect on how much water was retained.iann wrote:Testing peat-based potting soils for water retention is a nightmare. Baked dry, they will retain nothing, then easily soak up a cup of water if you leave it long enough. If the soil includes wetting agents, water crystals, etc, it could double the amount of water it might hold. Still, you might want to test your soil with nothing added.
Like the potting soil, I'm dense I don't quite get how this would be useful, in real world terms.iann wrote: The next step in the testing is to see how much more water you can add with the hole blocked. This is a measure of how much air was in the soil after it had been watered.
Cheers,
-R
It isn't how much water is in the soil that rots roots, its how little air. Obviously the two are linked to some extent, but using products like pumice instead of grit gives you more air and probably more water as well.I don't quite get how this would be useful, in real world terms.
Again pots are bad compared to an open planting because the perched water table effect inevitably reduces the air left around the roots. This is one of the reasons why potting soils are based on nice fluffy peat and not just the stuff in your yard.
--ian