Recycle potting soil?

[Pharmer Phil]

This may reap some comments/debate
OK, seems it is and has been a debate for some time I found
(after googling this)

Every spring, after we set plants out, or when we repot containers for the summer..we have leftover potting soil by the buckets, at least a third of what we purchased..give or take..

So, I have used this, both for adding to the garden...and to repot new plants for the coming season...
I have never had a problem...but then... maybe they could have done better?

I never sterilized it in any way
I never added any compost or vermiculite..
I can see the possible advantage of adding something like vermiculite to break it up some, and of course a good scope of compost is good fer any soil...but I never did..

So...
Opinions/comments/solutions/ condemnation

What ya think folks...would be nice to buy about 1 bag less of pro mix this coming spring...spring
Heck...we start onion seed..NEXT MONTH!!

[jerseycub]

Phil: I have wondered about that myself since I have several containers outside that we used for planting various vegetables on the deck last season. I was thinking about mixing it with the new horse manure, leaves and grass clippings that I started in sept. I suppose I could lay it out and burn it with my weed dragon. Ill ask one of the farmers up the road what he does.

[ChileFarmer]

Don't know how it might work in your area. But here in Texas I cover with black plastic and let the sun sterilize it. Haven't had any trouble from doing this. CF

[Rita]

I was always told to remove the top 1/3 of the soil and replace it with new to boost the nutritional value can't remember where I heard that but it made sense to me at the time .. .. it was quite a while ago

but I have always re - used the potting soil in the bottoms of the planters .. Usually to top off some pots in other areas of the yard ..
I do nothing to it .. the plants always seem fine

[mogarden]

I re-use unless the plant had obvious disease problems, then I just spread it out on the grass away from garden plants. I guess burning would be better but never did that. I'll have to decide soon since I have my containers from last year that will need to be fixed up and a couple new ones I want to add.

[Compost Pharmer]

My potting soil consists of about half compost and half top soil. What I have left over from one year, I use the next. The plants in pots, I just add more compost to the top, since what is in the pots has sunk down. Same with my one raised bed. I just top it off.
I see no reason that you can't use what you have left over from the previous year, but then I don't buy potting soil, but make my own. This way I know what goes into it.

[bluelacedredhead]

I seldom reuse it in containers at home, instead, I just empty containers into the garden and use fresh in the pots.
I have reused container soil in a greenhouse setting by adding to it however.

[jack]

Gidday

we just ruse the soil out of pots after repotting. Normally add a bitta new stuff because it is probably a bit depleted, and have never had any problems.

[Pharmer Phil]

JC, with outdoor planters like you mention. I dump them completely to remove any bugs..good or bad..and let them find a new home..
also with any "remains" from the seed flats I dump to remove any roots..figure they'd cause a problem decomposing ...
The Weed Dragon...is a great Idea!! Just happen to have one of those...never thought of it..

CF, I believe the black plastic could work here...but it most likely would need to spend the summer out in the sun up north here...but yet, still do-able...
just would havta be next seasons soil...or use it to pot up all the garden plants we bring inside for the winter

It seems that if a plant wasn't diseased, and the soil not over used (especially in the case of starting plants in the spring for the garden)...any leftover soil has hardly been used..that the soil should be ok...

I always purchase promix potting medium for the plants...they sit too long (sometimes longer than we care for them too) in the basement under lights...waiting for transfer to the greenhouse..any homemade mixes...seem to get heavy and compact by time to plant them out..

[jerseycub]

I always purchase promix potting medium for the plants...they sit too long (sometimes longer than we care for them too) in the basement under lights...waiting for transfer to the greenhouse..any homemade mixes...seem to get heavy and compact by time to plant them out..

I like promix as well, and I can tell you that I mixed the potting soil with composted soil in the planters last season and they are heavy as hell....so it does make quite a difference. I spoke to the fellow farmer up the road from us about soil recycling and he said he has a setup with pipe burners that he will use to cook the soil before reusing, and also offered it to me so I can sterilize my soil. Ill have to get some pictures of it to post in a few weeks.

[coppice]

I keep trees in pots. sometimes for decades. My bonsai soil has a far higher percentage of intentionally added inorganic material, than annual (like a tomato in a planter) or transplanting soil to grow into before planting to field.

Now just cause I sez so, don't make my observations law. But, here's what I've seen happening in my pots.

If you live where the water is hard and do not use rainwater to water your potted plants over time salts and limestone will build up in soil in pots. Also the organic material used with the addition of nitrogenous fertilizers completes the cycle of returning organic material to a state near to humus (or muck-with peat).

I could recover inorganic material like oyster shell or crushed granite from my potting mix, but I don't bother.

Once soil is tired it goes into compost bin and onto beds when the bins get dumped.

To a degree I want to agree with re users of potted soil, but the march to humus is a gradual decrease in soil particle size. An increase in soil compaction (in pots). It just never lead to 'next years soil reuse', working as well as fresh soil does.

Your mileage may vary.

[BestoFour]

Gosh I never even thought about not using it. I put it in the hole of the plant it came with and cover with additional dirt.

[mogarden]

Old topic but good one anyway. Last year was my first experience with gardening in containers other than pots of flowers/herbs of maybe a gallon or so. When I went to re-work the soil for 2012, I found my 18-gal totes had sort of mucky soil in the bottom 1/3 or so. As somebody said small particle size. So I emptied them and re-filled while adding larger organic material. I have had some, but not much bird-planted weed and grass seed but that's been easy to weed out. So far things look OK, we'll see if we have another scorcher summer or not.