I don't see why you shouldn't. Soil, as long as it is not diseased, serves just as a medium. All you have to do is replenish the nutrients.
I would just shake off and remove all the roots. To improve the thing cosmetically, you can mix a 50/50, ie 50% used and 50% fresh mix. Unless money is no object, then I will throw the old stuff in my veggies bed in the garden and use all NEW mix.

It depends, really.
Used soil tends to have finer particulate, which can compact and present a problem with drainage in containers. If the mix was very coarse to begin with, then it'll most likely have some life left - and all you'd need to address would be the pests, diseases, and nutrients (as mentioned). When re-using the 5-1-1, for example, I substitute 1 part of the old mix for the "peat" in the new mix. That's with plants I care about. With something like a willow, I don't hesitate to re-pot into an old mix.

Josh

I saved all of my 5-1-1 from last year and will just "recondition" it for use this year. I don't expect any problems.
Bruce

Josh:
I am not understanding what you are suggesting for reusing 5-1-1. My mix seemed to be pretty coarse last year and drained really well. I thought too well sometimes last year. So, what should I do to it when I go to repot this spring?
Thx,
Bruce

Bruce - I think the idea is that as stuff breaks down, you end up with too much very fine particulate matter. If you have too much water retention, you can screen out the smallest particles. An easy way (untested) might be to use a smallish screen and use a hose to wash the smallest stuff out, draining through the screen. That would be a lot easier than actually screening / sifting.

I have made 5-1-1 that didn't drain like I wanted and did the back breaking sifting, then added a smaller amount of peat (or potting mix depending on what I have laying around) back in. If / when I have to do it again, I will be trying a 1/4" screen and blast it with a hose, though, that may be too large and you would loose a lot of perlite as well. I dunno, but, there's got to be an easier way. :-)

Tsheets nailed it ;-) Thanks, man.
Yeah, if the mix is too broken down, it will hold a lot of moisture. But if the mix was real coarse the first season, it should be composted nicely in its second season. With the mix that is broken down, it can be used in place of peat / potting mix when making fresh 5-1-1.

Josh

Can I just re-use the 5-1-1 as it is or do I have to do something with it? I dont want to have to make any "fresh" 5-1-1 if I don't have to, although I have all the necessary ingredients if I need to.
Bruce

If you don't think it will be too retentive (doesn't sound like it from what you've said), I'd just freshen it up as you said. Add some more lime and CRF if you use it, and call it good.

Yes, Bruce, only you can tell if the mix still has enough structure and integrity. Add Lime, more CRF, as Tsheets mentioned, and it should be fine. I would probably add more Perlite, just to counter-balance the increased moisture retention.

Josh

I am starting to feel dumb now. What is CRF?

CRF - Control Release Fertilizer. Osmocote is what I found locally and use. Just to give you an idea.

OK, yep, I started out with a dose of Osmocote last spring and after a while, I added some water based ferts. Thanks tsheets.
Bruce

I've noticed the 5-1-1 to hold up very well. I'm saving all mine in a huge bag with holes punched in it so rain can run through it this winter and then just plan to refresh it with maybe another part coarse perlite, osmo, and more gypsum(it's a west coast thing, have no idea why Josh doesn't use it also -- his water is probably more acidic than my metro SoCal crap) .

I'm still concerned about the whole rotation of crops train of thought when it comes to container mixes though. In the ground, I'm able to give the usual 3 year rotation for the most part. To do it with containers, I'd need a helluva lot more containers... and mix! Maybe I'll just try to solarize it in a big rubbermaid tote. Thoughts?

Kevin

You know, Kevin, I had never thought about the crop rotation aspect. I'm no expert, but, here's what I am thinking. In the ground, you have the whole soil culture, in containers, much less so - at least in the smaller containers most of us use. Since most diseases come from the soil (at least that's what I read), I am guessing that the two are related. Since we supply all the nutrients in containers, there's really no worry with a plant using all of one nutrient. So, I'm thinking it's nothing to worry about unless you notice some sort of disease that you believe came from your container mix.

Be interesting to see what others have to say.

Kevin, I prefer the Dolomitic Lime because it provides both Calcium and Magnesium in a favorable ratio. If I used Gypsum, I'd have to supplement with Epsom salts to balance the Magnesium. I could do that, but it would be an extra step.

Those of us who are using *uncomposted* bark will almost certainly get more longevity out of our 5-1-1. Not all bark is created equally, of course, so I want to be sure to emphasize that the coarseness and integrity of the bark plays the most significant factor in whether to re-use, refresh, or dump last year's mix.

I don't give crop-rotation a thought....unless I suspect a virus or pest problem. Since we provide the nutrients to the container plant, we don't really need to worry about the "intensive farming" effect on the land.

Josh

Josh: I see. A lot of the AP soluble ferts do not have Mg. But with my city water coming in at a pH of 8.1, I opt to go with the gypsum. So, how much epsom salts and how often should I be adding. This past season I was using about a tsp per gal ever 3 weeks or so.

Kevin

Hey, Kevin. I'm going from memory now....
but I think you'd add a 1/4 teaspoon of Epsom per gallon, each time you fertilize.

Josh

With in groung application I use 1 Tbspoon of Epsom salt per 2 gal.once every month or so. But with potted application (in 511 ?), probably 1/2 tsp in 2 gal, every time sound logical to me. This is, of course, if the fertilizer you are using does not have magnesium..
I also foliar spray my tomatoes and peppers with a light solution of Epsom Salt once in a while.