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Wash your soil ingredients?

elgecko

I've got a magic window!
I usually wash my sphagnum peat moss before using, but not always..........

I was out of sphagnum peat moss so I went and bought some by Scotts.

I thought; lets have a bit of an experiment. Since I have a TDS meter lets see if washing the sphagnum peat moss will make a difference.
I took 12.8 cups of sphagnum peat moss and placed it into my bucket. I then added 1 gallon of collected rain water. All the rainwater I used in my experiments read between 0 and 1 ppm.
I mixed it all up. I took at least 5 reading while I let the sphagnum peat moss soaked in the water for a hour and a half. I got an average reading of 98.29 ppm. I was shocked how high this number was. Did you ever wonder where all the algae and slime mold comes from?
I wrung out the sphagnum peat moss and placed it into another bucket. I then added 1 gallon of rainwater and mixed. I left the sphagnum peat moss in the water for around 10 minutes, as I do not do a second wash. I only did this to take readings with my TDS meter. It came out to an average of 19.71 ppm.
So this little experiment does show that washing your sphagnum peat moss makes a huge difference to the amount of TDS in the soil.
I will always wash my sphagnum peat moss before use now.


But wait there's more.............


I also decided to check Scotts perlite.

I took 6.4 cups of perlite and placed it into my bucket. I then added 9.6 cups of collected rain water and mixed. I took a few readings over a 10 minute time period. I got an average of 16.4 ppm.
I then tried to get most the water out of the perlite and placed it into another bucket. Again I added 9.6 cups of rainwater and mixed. I took a few readings over a 10 minute time period. I got an average of 6 ppm.
Again, washing your perlite will help to lower the amounts of TDS in your soil.

Now this was a bit strange. I was going to dump out the bucket I used the first time to wash my perlite. I noticed a lot of sludge at the bottom on the bucket. So of course this meant sticking the TDS meter in the water again. What I find odd is that it read 44 ppm. When all the perlite was in the water, it measured much less, 16.4 ppm.
So then I remove the perlite from the second bucket. I measured that water. It measured 14 ppm. Again when the perlite was in the water it read 6 ppm.
I'm not sure why this is, but it does show one thing for sure. That washing your soil ingredients lowers the amount of TDS in your soil.

Hope you find this interesting or, useful.
 
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Thats very intresting elgecko, i always wash most of my potting mix befour using it, i wash off the perlite alot the peat i will start giving 2 rinses to, but have not rinsed the spag. The sand i use i just put it in a big bowl pour distilled water over it mix it with my hand then drain the water out. Thanks tons for the heads up and info.
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Good advice with experimental evidence to back it up.
 
Its "Total Dissolved Solids" which could loosely be translated as "the bad stuff".  And for anyone interested in this subject, there is an article on washing peat by William Dawnstar posted in the Articles Forum.  Many people are advocates of this technique but there are also those who think its a waste of time.  But I've known a lot of people who test the TDS in and swear by the benefits of washing their potting media.

Don't forget about the Articles forum.  Lots of good information there and we are adding to it whenever possible.  It is a good resource.  You will also find a link to BobZ's site with tons of photos to help in CP ID and general enjoyment. I see posts all the time asking for photos of such-and-such a plant.  When you think "photo"...think BobZ!  
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And yeah, I wash my peat and also leave my peat and sand bags out to leach in the rain.
 
That should put the final word on Scott's brand and the general concept of, "to wash or not to wash".
 
Thanks for the information Steve!I wash most of my soil mix,but not always.Plants that grow outside,I hardly ever wash the peat and sand.I just built a bog a few months ago and did'nt feel like rinsing 4 1/2 bales of sphagnum peat moss and 4 50 pound bags of sand.


Jerry
 
  • #10
I was just wondering, but could TDS cause retard growth in cp's?

-Ben
 
  • #11
I should get a TDS meter and test the peat I use. Just to know.
 
  • #12
[b said:
Quote[/b] (Drosera36 @ Dec. 22 2005,5:52)]I was just wondering, but could TDS cause retard growth in cp's?

                    -Ben
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That is a very good question Drosera36.
Anyone wana give input on this?

Thanks!!
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  • #13
I wondered about this myself... In nature, a lot of temperate dews grow on swamps, on sphagnum sometimes up to 10meters thick... and the water sure isnt even close to pure... last time I checked swamp water it had MAJOR bit of Fe in it. I'm also pretty sure it has some methane disolved in it as well as a load of other minerals and salts... so I'm just wondering... does it really matter? maybe sphagnum plays a role as a purifier? who knows...
 
  • #14
I always try to avoid Miracle gro, Scotts, and Schultz peat and perlite, just because those companies also manufacture fertilizers and try to infuse all their products with it.  

I'm not sure if a person can compare a large bog out in nature with a small pot full of peat and perlite.  Salts and minerals build up quickly in small pots.

Brian
 
  • #16
What I've read is that it should be no higher then 100 PPM. 50 PPM and lower being optimal.
 
  • #17
elgecko,

  Did you test the ppm of the water in native cp sites yet?  This summer I'm going to test Drosera and utric habitats.  I'm really curious what the results will be.  

Brian
 
  • #18
I never used to wash my soil ingredients. Then i got a TDS meter.

I was appalled how high the TDS readings of runoff water were when i watered my plants (100-150 ppm). There was a great deal of algae and slime mold, non-sphagnum mosses, etc. Some of the plants had stunted growth.

I flushed the pots out with rainwater until the TDS of the runoff came to 20 ppm or less.

I found that fresh, unwashed peat had a high level of TDS in the initial runoff.

My current soild mix for most of my indoor plants consists of 2/3 milled LFS, and 1/3 peat; I can't find pre-milled sphagnum, so i grind it myself in an old food procesor with the peat; this also breaks up lumps in the peat; i squeeza all excess water from the mixture.

I prepare many 3" suare pots in advance with this mixture (the milled sphagnum keeps it naturally light and airy, seed them with live sphagnum, and sit them in greenhouse flats outside, where rain further leaches the soil. When the surface is overgrown with live sphagnum, the pots are ready.

Since going this route, I have found my plants much healthier, especially since the live sphagnum helps retard algae/mold/non-sphagnum moss.
 
  • #19
elgecko,

[b said:
Quote[/b] ]...So then I remove the perlite from the second bucket. I measured that water. It measured 14 ppm. Again when the perlite was in the water it read 6 ppm.
I've also noticed different readings when measuring the same sample of perlite runoff - I assume this is due to small bits of perlite in the water.

Various particles in the sample water could cause spurious or inaccurate TDS meter readings based on the conductivity of the actual particles themselves. (think of those little floating bits as a possible 'short-circuit' in the conductivity of the water sample). According to the instructions that came w/ my TDS meter, macro particles in the water should not affect the meter readings. In practice I find that this may not be true... (perhaps they are refering to average particles found in tap water?) Perhaps the perlite has different properties that affect the capacitance of the particles.

I plan to re-measure some of my substrate ingredients using the TDS meter, but this time I will filter the samples through a coffee filter first. I am hoping that this will provide more accurate readings overall.

I still believe that the Scott's brand peat moss I have been using is rather high in dissolved salts (PPM). I don't think that the readings provided by my TDS meter are really accurate, but they are a great measure of relative dissolved solids. If I see lower PPM readings from the TDS meter, I know I am heading in the right direction.

I do believe that TDS meters can be very useful, but the readings provided must be taken with a grain of salt (groan).

If anyone if interested in learning more, here is some good information about the technical aspects of TDS meters (also, possible pitfalls of using a TDS meter to measure PPM concentrations, etc). http://www.reefkeeping.com/issues/2004-04/rhf/feature/index.php



Drosera36 wrote:
[b said:
Quote[/b] ]I was just wondering, but could TDS cause retard growth in cp's?
I had TDS once, but I've been taking pills for it...
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Actually, this is a good question: I believe that people have shown that many CP's have issues with overly high concentration of 'salts' in their soil. Just which salts or how they affect the plants is open to debate.

The problem with TDS meters is that they do not tell you what the 'dissolved solid' might be... what kind of salt, etc? So even though a TDS meter might read 300ppm, the plants might not mind so long as the dissolved solid(s) is not harmful.

I personally believe that a TDS meter might be a good measure of how suitable a soil/substrate might be. This is why I use one to track the readings in my watering trays, substrates, etc. If the readings are 'high', then I dump the tray water or rinse the media...

So to answer your question: maybe it just depends on the plants, the type of dissolved solid and the growing conditions you have. pH can also radically effect the way CP's react to different salts in solution.... food for thought.


- Mike
 
  • #20
Okay, now here is a question.
How do you "wash" out the soils and perlite?
I use rainwater to water my plants.

Sincerely,
Brendhan
 
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