Kelp use with recycled soilless mediums

[redneck shogun]

Has anyone in their experience in recycling their mix believe it became toxic over time by continuous use of kelp as a soil amendment? Do you think it could happen if unused micro-nutrients were to accumulate over time in the mix?

 

[Mr. Greengenes]

Well, I've been both using kelp meal and recycling my soil for at least twenty years now, and I haven't noticed anything yet.

 

[JackTheGrower]

What soil-less medium are you recycling?

 

[Mr. Greengenes]

JTG, I just mix my own 'by ear'. Usually it's got; sand, crushed gravel, lava, perlite, kellogs N-Rich, coco coir, compost from the pile in the yard, bone meal, kelp meal, greensand, crushed oyster shells, dolomite lime and whatever else I have kicking around. I'm very careful to sift all the old roots out of the mix before recycling. I just add back mostly nutritive, and non nutritive organics. Occasionally, I add back some non organics like sand or gravel, because they actually do get 'eaten up', just over a longer time period.

 

[TheGreenReaper]

I'm very careful to sift all the old roots out of the mix before recycling. I just add back mostly nutritive, and non nutritive organics.

Why do you remove the old roots in your recycled soil? Why not let them compost into the soil?

 

[OChack]

I've been doing the same; recycling my soilless mix for a long time. One of the benefits is you're keeping the beneficials alive for next time.

Here's a couple suggestions I do
1. I make sure to flush for 10-14 days before harvest. This ensures your mixture has been depleted for next round.
2. I pour all recycled soil into a separate pile next to your compost pile. The beneficial bacteria will help reduce remaining nutrients within a couple weeks.
3. I sometimes make a new mixture with 50% recycled and 50% pure peat moss. If I add any amendments I try to keep it to a minimum and allow the mixture to bake for a week or two.

Test your mixture !! Using a small net pot, fill it with your mixture, and run pure RO water over the top. Capture the run-off and measure the PPM. Great tool I've used the past that taught me "I was over feeding"