Experiment on drainage:benefits of layer of perlite on bottom of container

[Leon Sanders]

It seems logical that more air space on the bottom of the container would aid in drainage. Lots of people do it, both professionally and not. Again, it makes sense to those not versed in soil studies.

In past soil classes that I've taken at the collegiate level, it was shown this is actually untrue, and I plan on proving it. If I'm wrong, then that too will be shown.

It's all about surface tension. Perlite has a much harder time holding onto water then soil does. It also has a much harder time taking water from a different medium. Simply put, the soil will not give any water to the perlite, because the perlite isn't "strong" enough to take any. The only way water is going to leave the soil is through gravity (or saturation, same thing). Putting perlite under soil actually impedes the drainage.

I'll set up a few pots and record the time it takes to get to field capacity and how much runoff after 5 minutes (maybe less, maybe more, we'll see how it goes)

One pot will be soil with perlite on bottom
One pot will be coco with perlite of bottom
One pot will be soil
One pot will be coco
One pot will be soil with clay on bottom
One pot will be coco with clay of bottom

Suggestions are very welcome. I really just want to get to the bottom of this.

 

[PharmaCan]

I really just want to get to the bottom of this.

Ouch!

Terrible pun but great study! lol

I've never used perlite in the bottom of my pots, but I do put a little lava rock in before adding the coco. It'll be interesting to see the results of your study!

Good luck!

PC

 

[Leon Sanders]

I think the result will show that a properly aerated medium will have the best drainage, but who knows.

 

[Johnny Rotten]

I hope you don't mind me adding this here as I feel it touches on the same subject. Please disregard my attitude.
http://www.icmag.com/ic/showthread.php?t=96003
I totally agree with you about peat and it holding a reservoir of water. You can put a foot of perlite in the bottom of a 5 gal with peat on top and the peat will still hold water like a sponge.

 

[DIGITALHIPPY]

It seems logical that more air space on the bottom of the container would aid in drainage. Lots of people do it, both professionally and not. Again, it makes sense to those not versed in soil studies.

been there....

dug that....



i dont know why drainage is an issue. my plants gulp up water so fast i can bairly keep the soil moist for more then an hour or two.

if you really want to increase airation these guys will help alot more then some perlite... free castings too...


either way, enjoy the experiment, im sure itll smoke just the same.

 

[og dmc]

Your plants look fuckin healthy. Doin a good job there.

 

[Smoke68]

I always wondered this, but can you just throw a few worms into your soil and make castings as you use them?

 

[00420]

I'll set up a few pots and record the time it takes to get to field capacity and how much runoff after 5 minutes (maybe less, maybe more, we'll see how it goes)

One pot will be soil with perlite on bottom
One pot will be coco with perlite of bottom
One pot will be soil
One pot will be coco
One pot will be soil with clay on bottom
One pot will be coco with clay of bottom

Suggestions are very welcome. I really just want to get to the bottom of this.

how bout one with 100% perlite

 

[Orga_Nerd]

how bout one with 100% perlite

is that all u use as a medium?

 

[00420]

is that all u use as a medium?

yep!!!! it's the best imo ph ready/stable,easy to flush, max aeration but still holds plenty of water for plants....
(i have yet to use coco)

in my coli

in my waterfarms


and in 2 gallon bucket's


heres budding pic's of 100% perlite

 

[Erestese]

been there....

dug that....



i dont know why drainage is an issue. my plants gulp up water so fast i can bairly keep the soil moist for more then an hour or two.

if you really want to increase airation these guys will help alot more then some perlite... free castings too...


either way, enjoy the experiment, im sure itll smoke just the same.

I just did that with some low quality soil (MG Organic, first attempt) and the smell that came from the bottom of the pot was the most horrendous, foul, and putrid thing I've ever smelled in my life. It was so bad I dumped it outside and it created this aura of funk that consumed my neighborhood, grass loves it tho.

 

[medical_shed]

Agree with DigitalHippy on this. Noone uses perlite in a compost mix in agriculture why would you use it with cannabis? All it does is take up space in the pot that could have nutritious compost or roots instead. The cost adds up too.

I haven't used perlite since my first grow, a lot of people defend it to the death though.

If you're having problems keeping pots from drying out between watering use capillary matting, it also equalizes the moisture between all the pots.

 

[Chaghatai]

layers of different sized substrate often create barriers to H2O movement due to the vaugeries of surface tension. I've heard that the best drainage comes from a consistant, well-draining mix. All the H2O that is supposed to rapidly drain out of the more porous layer at the bottom must still percolate through the main medium anyway. The point is to ensure the H2O simply leaves the pot when it reaches bottom instead of pooling. Less-absorbant bottom layers are sometimes helpful because if H2O does pool, it is in out of the main root zone. Concievably, I cannot imagine any bottom medium draining better thn an open bottom with the largest mesh on the bottom that will hold the medium in. Main medium in the entire container. No layering needed.

 

[headiez247]

very cool, will be watching.

 

[Monad]

Great Thread, I've been contemplating lining the bottoms with perilite for sometime.

 

[DIGITALHIPPY]

Agree with DigitalHippy on this. Noone uses perlite in a compost mix in agriculture why would you use it with cannabis? All it does is take up space in the pot that could have nutritious compost or roots instead. The cost adds up too.

I haven't used perlite since my first grow, a lot of people defend it to the death though.

If you're having problems keeping pots from drying out between watering use capillary matting, it also equalizes the moisture between all the pots.

it does seam like a waste.
ive never had any 'wet' problem in my soil anyways drainage is a non-issue.
people here sure do like there perlite. i found ti a waste, adding a bit of perlite chouldnt hurt though. perlite holds water too...

 

[00420]

http://www.perlite.net/

http://www.perlite.net/redco/indexh.htm

 

[caljim]

I agree with digitalhippy. used to put alayer of perlite at the bottom of the pots hoping to avoid overwatering problems....now i find the sunshine mix#1(has less perlite than #4) works just fine.......its all about goog root mass and proper watering.......I even kick in a bag of compost to help hold some moisture in the soil.

 

[Pig-Pen]

Well?