Can you reuse soil after a harvest?

elusiveshame · Feb 13, 2023

So since good potting soil is expensive ($40 for 2 sq feet), I’d like to try and keep costs down if possible.

Can you reuse soil after you harvest? Does anything special need to be done to make the soil friendly for plants? Add some dolomite lime? Just start using nutrients right off the bat?

Thanks!

Homesteader · Feb 13, 2023

Of course but you may want to use it on a lower value crop like tomatoes and get fresh soil for cannabis (at least until you understand how to make and amend your own)

elusiveshame · Feb 13, 2023

Homesteader said:
Of course but you may want to use it on a lower value crop like tomatoes and get fresh soil for cannabis (at least until you understand how to make and amend your own)

Well how do you make and amend the soil? That's kind of what I was asking. Can you reuse it followed by what needs to be done.

BigBlonde · Feb 13, 2023

My thinking is that soil can be reused forever. The problem is how to keep it vital. Mixing it with fresh soil and organics will help do that. So will adding amendments. I like to grow other plants, like tomatoes and flowers, so I never throw soil away. If I can't think of anything to do with it, I add it to my compost and let microorganisms do their thing.

KenKenaf · Feb 13, 2023

Can soil be reused? Nope that's why Father Elon is taking us to Mars.

Lots of guys do no-till. How much you reamed depends on how much you feed. You can do a soil test. Somewhere there's a calculator of nutrient values for various inputs https://soilworksllc.com/soil-testing/

Anthem · Feb 13, 2023

BigBlonde said:
My thinking is that soil can be reused forever. The problem is how to keep it vital. Mixing it with fresh soil and organics will help do that. So will adding amendments. I like to grow other plants, like tomatoes and flowers, so I never throw soil away. If I can't think of anything to do with it, I add it to my compost and let microorganisms do their thing.

You can reuse soil, but you have to have a better understanding of the properties and depletion of the nutrients in the soil to do so. I know a guy that has been reusing his soil for about 6 years. He uses one for a grow while the other is recharging. Starts off by boiling the soil and then he adds back in the depleted nutrients. I know he has a degree is ag or something and it not the average Joe. It can be done but it is not for beginners.

2Bad · Feb 13, 2023

KenKenaf said:
Can soil be reused? Nope that's why Father Elon is taking us to Mars.

Lots of guys do no-till. How much you reamed depends on how much you feed. You can do a soil test. Somewhere there's a calculator of nutrient values for various inputs https://soilworksllc.com/soil-testing/

Yeah I was gonna say a soil test. And maybe google how to break down roots with enzymes. Then just reammend with Gaia green or any dry ammendment line.

mysticepipedon · Feb 13, 2023

The issue is that you don't know what's left in the soil. It could be a lot of some nutrients, a little of others. That can cause problems with the next crop.

I know someone who leaches a lot of stuff out with several washings of water. But that doesn't take everything out, just stuff that's easily soluble in water. I don't chance it, and I'm a frickin' soil scientist. It's a lot of hassle. You'd be better off learning a hydro technique, IMO, if you want to reduce soil waste.

I do reuse it in my veg garden. Nobody in my neighborhood has tomatoes like mine! No one has asked about why there's so much perlite yet. Maybe I should think of an answer before that happens. LIke there was a huge perlite deposit in my yard.

RootsRuler · Feb 13, 2023

mysticepipedon said:
The issue is that you don't know what's left in the soil. It could be a lot of some nutrients, a little of others. That can cause problems with the next crop.

I know someone who leaches a lot of stuff out with several washings of water. But that doesn't take everything out, just stuff that's easily soluble in water. I don't chance it, and I'm a frickin' soil scientist. It's a lot of hassle. You'd be better off learning a hydro technique, IMO, if you want to reduce soil waste.

I do reuse it in my veg garden. Nobody in my neighborhood has tomatoes like mine! No one has asked about why there's so much perlite yet. Maybe I should think of an answer before that happens. LIke there was a huge perlite deposit in my yard.

Wouldn't feed method have a large part to play in "depleted soil"? If I'm dumping bottled nutes into the soil then whatever nutrient composition the soil has takes a backdoor to readily chelated liquid fertilizers right? In other words, the plant is relying on manual feeding rather than organic matter being broken down into soluble ions that the plant can use. Certainly these organic reactions are important in having a readily available food source for the plant but it would seem that if you're supplying it with readily available food whatever food the depleted soil is able to produce would be secondary to the plant.

Also, if I'm reusing potting soil that I've grown in before and am using bottled nutrients would not whatever residual salts that are left in the soil be enough to recharge the soil with readily available ions? I know that some will veg with only water for about a month using the natural nutrients that the soil provides but if you're using liquid fertilizer from the start then, again, you're providing the breast milk not the mommy.

BTW I need some tips on growing heirloom tomatoes. Those bastards are finicky as all hell.

2Bad · Feb 13, 2023

mysticepipedon said:
The issue is that you don't know what's left in the soil. It could be a lot of some nutrients, a little of others. That can cause problems with the next crop.

I know someone who leaches a lot of stuff out with several washings of water. But that doesn't take everything out, just stuff that's easily soluble in water. I don't chance it, and I'm a frickin' soil scientist. It's a lot of hassle. You'd be better off learning a hydro technique, IMO, if you want to reduce soil waste.

I do reuse it in my veg garden. Nobody in my neighborhood has tomatoes like mine! No one has asked about why there's so much perlite yet. Maybe I should think of an answer before that happens. LIke there was a huge perlite deposit in my yard.

What's the issue with soil tests?

AnimalHouse · Feb 13, 2023

Homesteader said:
Of course but you may want to use it on a lower value crop like tomatoes and get fresh soil for cannabis (at least until you understand how to make and amend your own)

Best veggies I grow every year are done in used ganja farm soil. Mine is kept organic so there's no salt build up or anything outta whack. Just good rich dirt with lots of life left in it

mysticepipedon · Feb 13, 2023

RootsRuler said:
Wouldn't feed method have a large part to play in "depleted soil"? If I'm dumping bottled nutes into the soil then whatever nutrient composition the soil has takes a backdoor to readily chelated liquid fertilizers right? In other words, the plant is relying on manual feeding rather than organic matter being broken down into soluble ions that the plant can use. Certainly these organic reactions are important in having a readily available food source for the plant but it would seem that if you're supplying it with readily available food whatever food the depleted soil is able to produce would be secondary to the plant.

Also, if I'm reusing potting soil that I've grown in before and am using bottled nutrients would not whatever residual salts that are left in the soil be enough to recharge the soil with readily available ions? I know that some will veg with only water for about a month using the natural nutrients that the soil provides but if you're using liquid fertilizer from the start then, again, you're providing the breast milk not the mommy.

BTW I need some tips on growing heirloom tomatoes. Those bastards are finicky as all hell.

Soil is not inert.

If you are using soil, it has what is called cation exchange capacity (CEC). This allows positively charge ions (many nutrients are taken up by the plant as positively charged ions, like potassium, calcium, magnesium, iron, manganese, copper, zinc, and others). to be held by the soil, sort of in reserve. It is released slowly to the plants. It doesn't easily wash out.

You also end up with different nutrients reacting with each other, forming compounds of low solubility, which also don't easily wash out of soil. These can become available to plants at unknown rates, so when you are feeding on a regular schedule, you won't know how much is also being released by these leftover compounds.

Heirlooms: They're like regular tomatoes, only moreso.

The main issue I have with heirlooms, is that many are crack addicts. The only way I've been able to stop varieties like Black Krim from cracking is to water every morning. If the soil dries and then is suddenly wet again, the plant will suck in water in over-abundance, and fruits swell and crack.

Then, tons of calcium. I've never seen calcium lockout with these bastards.

Aqua Man · Feb 13, 2023

The whole point to organic growing is to reuse the soil. Really good soil is developed over years and if your growing organically its a waste to throw it out after each grow.

on a large scale soil testing is done and amendments are added based on results.

im not an organic guy so im not the guy to help you with this. I have a lot of respect for those who do organics right and build their soil structure year after year

RootsRuler · Feb 13, 2023

mysticepipedon said:
Soil is not inert.

If you are using soil, it has what is called cation exchange capacity (CEC). This allows positively charge ions (many nutrients are taken up by the plant as positively charged ions, like potassium, calcium, magnesium, iron, manganese, copper, zinc, and others). to be held by the soil, sort of in reserve. It is released slowly to the plants. It doesn't easily wash out.

You also end up with different nutrients reacting with each other, forming compounds of low solubility, which also don't easily wash out of soil. These can become available to plants at unknown rates, so when you are feeding on a regular schedule, you won't know how much is also being released by these leftover compounds.

OK. So I see the issue with mystery ratios of compounds affecting others but my point is the source of food. Much like in a hydroponic setting where the media has no nutritional effect on the plant as much as it being a structural vehicle for the plant. If no food production is needed from the media then, aside from the weird reactions you mentioned, the amounts left in the soil shouldn't be a factor since those are being provided synthetically.

I'm just not sure if the reactions you mentioned would be enough to have a detrimental effect on the plant.

I usually recharge my soil by mixing in a 50/50 mix of new and old soil along with a few amendments like lime. worm castings, blood meal, fish meal, bone meal, etc.

NorthernOrganics · Feb 13, 2023

I've had luck with topdressing with ground up malted barley during the last couple weeks. You have to grind it up right before you topdress. Malted barley is high is enzymatic activity and if introduced near the end of flowering, last couple waterings, it is supposed to help finish the plants and increase resin. After I chop them I just leave the pots to the side with whatever water and roots are in there and in two weeks the enzymes have eaten all the roots up, I can pluck the trunk off the top of the soil. I have, in past grows, just dumped all the pots into a basin and added a bunch of dry amendments and let it sit for a couple more weeks. The plants grown in "round two and three" soil were fine, more finicky maybe, but the bugs got bad. Fungus gnats and springtails everywhere. I much prefer now to use fresh soil for cannabis and used soil for the outdoor veggies. The malted barley attracted pests indoors, but no rootballs to deal with.

Aqua Man · Feb 13, 2023

@Homesteader @oldskol4evr are 2 guys that i would call on if i was going organic soil. I know there are plenty more here with great knowledge of organic growing so please don’t feel left out if your not them. Just going off the top of my head from the amount of awesome help given that I’ve seen.

having said that ima gonna run my salty ass out the door. Organics scare me

RootsRuler · Feb 13, 2023

Aqua Man said:
@Homesteader @oldskol4evr are 2 guys that i would call on if i was going organic soil. I know there are plenty more here with great knowledge of organic growing so please don’t feel left out if your not them. Just going off the top of my head from the amount of awesome help given that I’ve seen

As much as I love organic soil growing it's just way too much work for me!!!

Aqua Man · Feb 13, 2023

RootsRuler said:
As much as I love organic soil growing it's just way too much work for me!!!

I have my opinions and they ain’t popular with most of the new organic crowd. To me watching people throw soil out after an organic grow makes my head explode. May aswell just grow with synthetic nutrients then.

ok yeah at the risk of derailing im out good luck

2Bad · Feb 13, 2023

Aqua Man said:
I have my opinions and they ain’t popular with most of the new organic crowd. To me watching people throw soil out after an organic grow makes my head explode. May aswell just grow with synthetic nutrients then.

ok yeah at the risk of derailing im out good luck

Yea ain't no way im doing that. i'll figure it out haha.

Stonemason7767 · Feb 13, 2023

I reuse my soil.im on my 4th run in a 30 gallon.i do soil horizons when I build the 30 gallon.bottom 2 inches fieldstone and sand.next 6 inches is a loam which is clay and sand 40percent clay 40 sand 10 percent soil mix.top 10 inches are my soil mix which is compost, peat,pumice and mulch and rice hulls.a few amendments and some indigenous mico organisms beneficial bacteria 25 worms.i feed the plants and the microbiology with organic water soluable nutrients. Compost all the leaves and stems from the grow back in and leave the roots.not planning on changing my dirt for years.

Can you reuse soil after a harvest?

Can you reuse soil after a harvest?

elusiveshame

Homesteader

elusiveshame

BigBlonde

KenKenaf

Anthem

2Bad

mysticepipedon

RootsRuler

2Bad

AnimalHouse

mysticepipedon

Aqua Man

RootsRuler

NorthernOrganics

Aqua Man

RootsRuler

Aqua Man

2Bad

Stonemason7767

Privacy & Transparency

Privacy & Transparency