Recycling used potting soil

[ChanellG]

So I have this large container sitting outside from ages ago full of dirt I would like to reuse. I was all set to recycle it via composting until I saw something online that actually discouraged that. I wanted to do it in the first place because of something I had read a while ago, but I couldn't remember where.

I have been reading up again and today I found a long thread about it where people were recycling the soil from seasonal plants that they had let completely die off first. Some sterilize the soil, some just let it sit in the sun, others throw it down on the ground like mulch or use it to supplement beds.

No one has said they have ever had a real problem with reusing soil. As far as I can recall, I don't think I've ever had any diseased plants so I am guessing the soil should be okay, especially since it has been sitting for so long.

Any thoughts?

 

[dhrynio]

It is a really good question. I really don't see why not. In the Square Foot Gardening book Mel talks about using your previous years soil and just ammending it by adding fresh composts. So I would think that using old soil and adding enough new compost to bring up the nutrient level would be fine!

 

[Tmann]

If you are concerned about disease you could always scoop it into an old roasting pan and stick it in the oven and cook over 350 for 15 minutes should kill anything that may be living.

 

[ChanellG]

If you are concerned about disease you could always scoop it into an old roasting pan and stick it in the oven and cook over 350 for 15 minutes should kill anything that may be living.

Yeah, not really wanting to do that. It would be too much of a hassle, then there is the smell, the mess... Easier to just deal with it outdoors.

It is a really good question. I really don't see why not. In the Square Foot Gardening book Mel talks about using your previous years soil and just ammending it by adding fresh composts. So I would think that using old soil and adding enough new compost to bring up the nutrient level would be fine!

But Danni, is he saying to just top off the beds or to actually dig up the soil that's there? What I would be doing is putting the old dirt into the compost bin with the kitchen scraps, etc. The only real concern is possible pathogens, but how would you know what's in the soil?

 

[maddie]

@ Channel, I always reuse potting soil. I have never had a problem with that.. I generally treat the soil with a good spray of neem oil after loosening it up leave it out for a couple of days and then reuse it.
I have never had any diseased plants too so far.. I guess you would have issues only when you have some plants with disease that might affect other plants.
Don't quote me on this... but my experience over twelve years has always been good.

 

[Jed]

My wife had been reusing old potting soil for years. She made up her own potting mix to pot plants for sale at markets. If they didn't sell she'ld let the plants die off and reused it adding some pelletized chicken manure.
So I'ld say depending on a few issue such as weeds and if the plants had diseases would be the deciding factors.

 

[ChanellG]

@Maddie
@Jed
Thanks! I have started slowly adding old soil to the new compost bin I finally set up outside. My only concern is whether or not there will be enough heat in the bin since there's been so little sun lately.

It's light out at 7:00 am and get's dark at 5:30 pm or so, but it hasn't been that sunny. Tomorrow there's a 30% chance for rain again...

 

[blueiris]

I usually will take old potting soil and add it to new potting soil about half and half. Sometimes I add pellet plant food to the mix and water it, well. Then I save it for a week or two and use it. I haven't had any problems using this mix for container planting.

 

[ChanellG]

Thanks for that info. I haven't been able to come up with any reason for not using the dirt I have in the container. I suppose I could dump some of it out on some plastic or newspaper and leave it in the sun first. We're having nice weather so maybe I'll start doing it tomorrow.

 

[ACSAPA]

I wondered about this too ,because I've had Christmas-y plants or other potted plant gifts that died, leaving a pot of okay-looking potting soil.
I've always wondered if I could use that dirt again. I like ChanellG's compost idea, because all the good nutrients in that soil were probably used up by the previous plant, so making it part of the compost pile probably enriches it and makes it good soil again.

 

[ChanellG]

I've been using the dirt from the old container to top off the kitchen scraps I put into the compost bin. It's still too cool out for me to think there's been that much activity in the bin, but I'll probably go out and turn the contents soon and maybe pile on a little more dirt. I would imagine it was only the topsoil that would be in question and that has been sitting out in the sun for so long, I doubt it would be a real issue now. (At least based on what I've read.)

 

[ChanellG]

Well, by now everyone knows how excited I was to find worms in my dirt, lol. After reading about leaf mold I am thinking that bagging the leaves and adding a bit of old potting soil and some paper is a good way to get the leaves composted and ready for use sooner. I'll have to find a sunny spot to do this so that the bags maintain their heat during the winter.

@Shellyann36 how do you recycle old potting soil?

 

[Shellyann36]

Well, by now everyone knows how excited I was to find worms in my dirt, lol. After reading about leaf mold I am thinking that bagging the leaves and adding a bit of old potting soil and some paper is a good way to get the leaves composted and ready for use sooner. I'll have to find a sunny spot to do this so that the bags maintain their heat during the winter.

@Shellyann36 how do you recycle old potting soil?

As long as there is nothing wrong with it I put it back into the compost pile. If by chance there is something wrong, the plant died of some diease or something I dump it far far away from any of my plants or garden.

 

[ChanellG]

As long as there is nothing wrong with it I put it back into the compost pile. If by chance there is something wrong, the plant died of some diease or something I dump it far far away from any of my plants or garden.

That is pretty much what I do as well, though I usually leave the old stuff out in the sun for a bit after removing the plant before I put it in the compost bin. So far so good, and I really am enjoying the process of doing all these things. I just hope I don't get too busy to keep it all up in the coming weeks and months.

 

[Shellyann36]

That is pretty much what I do as well, though I usually leave the old stuff out in the sun for a bit after removing the plant before I put it in the compost bin. So far so good, and I really am enjoying the process of doing all these things. I just hope I don't get too busy to keep it all up in the coming weeks and months.

I hope that you are able to manage it. With the cooler weather coming it should give you a break. Or does New Orleans stay warm year around? I have always wanted to visit but I never have so I don't know how your winters are.