Reused Grow medium

[Capn-Crunch]

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]

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.

 

[hotrodharley]

And I just use water with molasses the last 10 days when I'm growing out a regular crop.

 

[vostok]

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]

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]

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]

Nurseries do it all the time, just re-amend it and you're good to go.

 

[Midnight Warrior]

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]

And I just use water with molasses the last 10 days when I'm growing out a regular crop.

The medium was from a couple plants that got hit with frost last year, there was no time to flush

 

[Capn-Crunch]

I don't nute clones so early

using used soil is the best

and gradually introduce nutes over time

good luck

I've always used 300ppm for clones with no issues. It just didn't dawn on me that the medium would be so hot, lol

 

[Capn-Crunch]

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.