100% Coco for passive hydro; perlite ph question

TreeWalker

TreeWalker

Member
Perlite has a PH of 7-7.5 which isn't right for healthy hydro PH in the rez.
Coco has an almost ideal PH in the range of 5.2-6.8.

This makes me question the use of perlite in my hempys, although I have used it successfully. But I believe it may be the cause of rising PH in my buckets. PH drift is a good thing and I use it but perlite is off the charts for cannabis PH. I want to drift from 5.8 to 6.5 in general.

I am going with new buckets 5 gallon top and 2 gallon reservoir (much bigger than I used before) and was considering going with a water only rez but now am questioning this decision as there may be a gap between the bottom of the coco and the top of water. Roots growing in that gap may get dry.
There are 3 legs on the divider which reach the bottom of the rez and roots will be present there.
These buckets are designed to have water only in the reservoir and for tomatoes. Here they are Hydro Farm Tomato Barrels: https://www.amazon.com/Hydrofarm-GCTB-Tomato-Barrel-4-Foot/dp/B004NBZDN6

My questions are:

1. Will a gap between the bottom of the coco and the top of the water be an issue for roots? The water levels will rise and fall even though I plan to use a float valve in each to gravity fill the rez. If using liquid only in my drain to waste setup is a bad idea then...
2. Why not use 100% coco instead of perlite in the rez? I use a pretty chunky coco with some chunks the size of quarters. Why not use a medium that is better suited for my PH range?

Why are so few using 100% coco in hempys/passive hydro? I have seen some in the past but cannot find them now.
Thanks
 
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rkymtnman

rkymtnman

Well-Known Member
Perlite is crushed aluminum-silica volcanic rock, which has been heated rapidly to very high temperatures, during which process it expands to a lightweight, chemically inert, and sterile material. Perlite has no nutrients, and with a pH of 7 to 7.5 (neutral) it does not contribute to the substrate pH
 
eyderbuddy

eyderbuddy

Well-Known Member
I highly doubt that your perlite is causing PH fluctuations in your water. That's likely to be bacteria.

Few use 100% coco because it naturally holds TOO much water, which is counter productive for Cannabis. Growth rate is way better for me when mixed at a 1:1 ratio
 
Nrk.cdn

Nrk.cdn

Well-Known Member
Thoae amazon tomatoe barrels are just overpriced SIPs. Can achieve same setup with a net pot, 2 - 5 gal buckets, and tomatoe cage..search sub irritated planters.. There is a good thread on riu.

You might need to change lower rez every 2 weeks..setup better for a blend with organics.. Good luck and send grow pics..
 
Skunk Baxter

Skunk Baxter

Well-Known Member
eyderbuddy said:
I highly doubt that your perlite is causing PH fluctuations in your water. That's likely to be bacteria.

Few use 100% coco because it naturally holds TOO much water, which is counter productive for Cannabis. Growth rate is way better for me when mixed at a 1:1 ratio
Click to expand...
I use a blend of about 35% coir and 65% coco chunks. To me, that's the perfect balance - an ideal combination of drainage and moisture retention, aeration and hydration, through all phases of the grow. I hate perlite, because i re-use my coco, and that crap is just a colossal pain in the ass to rinse and flush. I highly recommend you try it sometime; I suspect you'll never go back.
 
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