Soil re-use

Hello all,

Just a wee question to anyone out there who uses "synthetic" nutrients rather than totally organic grows.

Do you re-use your soil? If you do, any issues with nutrient build up? And if so, how do you reduce that or mitigate the effects? It's been suggested by another grower to flush/rinse the soil before use / re-mixing, but I wonder if this will be sufficient and/or necessary?

So any non-organic / semi-organic growers re-using soil? Or do you just buy new each time?

I’m organic to start with initial soil, then as the grow progresses I use synthetic fert. I wouldn’t flush it. I reuse it for my tomato plants, they grew with the same fertilizer put in and it grew really well, I don’t see a problem with reusing for cannabis just as long as it’s not way out of wack to begin with. I would say if your real good at spotting nutrient deficiencies than by all means reuse it. That’s what fertilizer is for. Did you have issues with your soil? Plants look relatively healthy till harvest?

I reuse my soil which is a combination of FFOF/HF, Sierra Gold[local?], and Big Rootz.

When I'm done with a grow, I'll rip out the core of the trunk and roots and toss the used soil in an old Ocean Forest 3.8cuft bag. I recommend sealing the bag for two weeks if you've had gnat issues.
Once the Ocean Forest bag is "full enough" I'll add roughly 6 red cups of local organic compost and 6 red cups of earthworm castings and a couple tablespoons of oyster shell.
At that point, I transfer over to an ice chest, add some bennies and mycos and mix it thoroughly, add enough water to be lightly damp, not wet, and mix again. Then it sits until I need it.

Currently, I'm moving everything over to just a Promix/compost/casting mix that should get me from transplnt to pistils, then I can supplement with salt when necessary.

There's no science to my ratios, just adding an amount that 'feels' right and so far the plants aren't disliking it.

And as Hairybuds said, no flush, let it all marinate.

Thanks folks for the advice. The reason I asked was I have been re-using soil, and cutting it with a 50/50 mix with fresh soil (my mix is compost, peat moss, perlite and vermiculite). However in my second grow last year I had really bad nutrient burn, and I suspect that rather than directly overfeeding, there was a build up of salts in the soil over time which led to problems. I still got a harvest, but the plant looked terrible at the end!

I like the suggestion of re-use for a different crop. I grow vegetables and some tomatoes and peppers might seek out a different mix of nutrients from the used soil than my cannabis (currently mostly auto flowers which seem a bit more sensitive to nutrients). I also agree with the principle of modifying and enhancing used soil. Just maybe this particular batch has gone a bit out of balance, at least for growing weed indoors under artificial light.

So I think I will get some fresh mix together for the coming grow, and re-use this used batch for other crops this time around.

trychrome said:

I reuse my soil which is a combination of FFOF/HF, Sierra Gold[local?], and Big Rootz.

When I'm done with a grow, I'll rip out the core of the trunk and roots and toss the used soil in an old Ocean Forest 3.8cuft bag. I recommend sealing the bag for two weeks if you've had gnat issues.
Once the Ocean Forest bag is "full enough" I'll add roughly 6 red cups of local organic compost and 6 red cups of earthworm castings and a couple tablespoons of oyster shell.
At that point, I transfer over to an ice chest, add some bennies and mycos and mix it thoroughly, add enough water to be lightly damp, not wet, and mix again. Then it sits until I need it.

Currently, I'm moving everything over to just a Promix/compost/casting mix that should get me from transplnt to pistils, then I can supplement with salt when necessary.

There's no science to my ratios, just adding an amount that 'feels' right and so far the plants aren't disliking it.

And as Hairybuds said, no flush, let it all marinate.

Click to expand...

That’s how I did my first grow, a mix of amended soil then when it ran out used salt nutes. Was tricky during the transition though.

Milky Weed said:

That’s how I did my first grow, a mix of amended soil then when it ran out used salt nutes. Was tricky during the transition though.

Click to expand...

I don't plain-plain water feed anymore. depending on what the plant looks like i.e. is it too dark, too 'bright', I'll add a drop of silica and/or a drop of calcium and about 1ml of nutes. The only time I've had any issues was when I tried to ditch the RO for filtered tap. Someone with better water than mine might not have the same issues I experienced[super-elevated pH].
Otherwise there shouldn't be much of a bump during the transition if you're not getting crazy with anything.

I also reuse FFOF. I add perlite to the soil when its new. after harvest, let the pots dry completely and shake as much soil from roots as possible, removing any root balls that is still in the soil. Random root strands is ok. Then add per gallon of soil: 3tbs azomite and 2tbs hydrated lime.

at this point, the soil is essentially a soil-less medium with added buffer and trace minerals. treated as such it works like a champ