Reused Grow medium

Capn-Crunch

Well-Known Member
A couple weeks ago I needed to pot up a few clones so I went in the garage and got some amended peat that I
used last year to grow in. Planted the clones and watered them in with a 300PPM nute solution.
After a few days they started showing nute burn so I ran some water through the pots and when I
tested the runoff it was 2600PPM!
Anyone else ever run into this? I didn't think that there could ever be that much residual nutes left in that old mix.
 

hotrodharley

Well-Known Member
A couple weeks ago I needed to pot up a few clones so I went in the garage and got some amended peat that I
used last year to grow in. Planted the clones and watered them in with a 300PPM nute solution.
After a few days they started showing nute burn so I ran some water through the pots and when I
tested the runoff it was 2600PPM!
Anyone else ever run into this? I didn't think that there could ever be that much residual nutes left in that old mix.
I leave mine outside to be rained on and rinsed. But this winter I was forced to reuse some that had not been weathered. It was a nightmare. It was for flowering clones I was putting into flower. It was the end of flowering before it even got close to normal. Never again.
 

vostok

Well-Known Member
A couple weeks ago I needed to pot up a few clones so I went in the garage and got some amended peat that I
used last year to grow in. Planted the clones and watered them in with a 300PPM nute solution.
After a few days they started showing nute burn so I ran some water through the pots and when I
tested the runoff it was 2600PPM!
Anyone else ever run into this? I didn't think that there could ever be that much residual nutes left in that old mix.
I don't nute clones so early

using used soil is the best

and gradually introduce nutes over time

good luck
 

ColoradoHighGrower

Well-Known Member
What if you make a slurry with ph'd water to fully rehatdrate the an old soil mix, let it equilibriate, and measure ppm of the slurry before deciding to go with it or to flush it first? Thoughts @hotrodharley ? How do you do it @vostok ? I'm up to 35-45 gallons of soil, so sure would be nice to be able to reuse once or twice...
 

hotrodharley

Well-Known Member
What if you make a slurry with ph'd water to fully rehatdrate the an old soil mix, let it equilibriate, and measure ppm of the slurry before deciding to go with it or to flush it first? Thoughts @hotrodharley ? How do you do it @vostok ? I'm up to 35-45 gallons of soil, so sure would be nice to be able to reuse once or twice...
I've never had a problem with used soils until this last run. Flowering clones so they were being fed. Before symptoms appeared.
 

Midnight Warrior

Well-Known Member
What if you make a slurry with ph'd water to fully rehatdrate the an old soil mix, let it equilibriate, and measure ppm of the slurry before deciding to go with it or to flush it first? Thoughts @hotrodharley ? How do you do it @vostok ? I'm up to 35-45 gallons of soil, so sure would be nice to be able to reuse once or twice...
Nurseries do it all the time. Wouldn't hurt to throw it in a compost pile for awhile so any residual nutes can break down, then re-amend it.
 

Capn-Crunch

Well-Known Member
The 15 clones I have in that soil can't be pulled without killing them, so just water and hope they all make it.
I have another 20 clones that will be ready to plant in a week, so will use fresh medium with them.
 
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