another goofy question

[z-man]

Well, Another one of my goofy questions,but somebody's got to ask it. The past couple of months I have been growing tomatoes in a earthtainer,now soon I'll be getting ready to plant again. Now my question is after the old plant has been removed from the earthtainer. What do I do to rejuvanate the soil mix for the next planting or do I not use it now and save it. Buy new soil mix and start fresh? I really like this form of gardening and want to continue my tomatoes using this method. Thanks for any replys Z-man

[dice]

Well, how can it have changed? Some of the organic matter
in it will have broken down to silt, and some larger structures
to smaller structures in general, so it will have lost large pore
air space. If the plants had disease, then it could have disease
spores in it. If that is true, you probably want to spread it out
thin between sheets of clear plastic and solarize it for a couple
of months before reusing it. To restore large pore air space,
you can spread it out on a window screen over a wheelbarrow,
let it dry out completely, and shake the silt and other fine
particles out of it. You can replace what shakes out by volume
with some kind of larger structured organic matter (more
bagged potting mix, peat, pine bark fines, compost, leaf mold,
coir, thoroughly composted manure, mushroom compost, etc).
Any kind of rock or perlite too big to pass through the screen
will not be breaking down quickly at all, so that part will last for
years.

Some people take the short path: either take half of it out
and mix what's left with new commercial container mix, kind
of a compromise between the large pore air space in all new
mix and what was left after a season of growing in it, or
simply toss it all and replace it. Kind of depends on whether
you have more time or money.

One other course is to cut last season's plants off at soil level
rather than pulling them, and count on the old roots to replace
large pore air space that was lost from organic matter decaying
to silt. People might use the same container full of mix for
3 years this way before finally replacing it. With the root
diseases that tomatoes regularly get, this is kind of risky.
(Probably works better with crop rotations, where someone
is growing quite different vegetables in the same containers
in successive seasons.)

An excellent document on the characteristics of quality
container mix can be found here:

http://edis.ifas.ufl.edu/CN004

Edit:
PS: I like to let the rain rinse it pretty thoroughly after shaking the
silt out and before mixing more organic matter with what was left
after sifting. This washes out salts that build up in it from fertilizers,
municipal water or brackish well water, etc. I just fill up containers
that drain well with what is left after sifting (which has about the
consistency of cactus mix: lots of air, excellent drainage, and less
organic matter than it had originally) and let them sit out in the
rain until I am satisfied that they have been thoroughly rinsed,
at which point the stuff is ready for remixing and reuse.

[amideutch]

Z-Man, here is what Ray had to say about his EarthTainer and reusing the aggregate. Ami

My goal is to not have to take each EarthTainer apart every season and clean out all the roots out of the water reservoir, but to get a 3 year life cycle before having to do this time consuming operation.

My hope is that the landscape fabric will contain the root ball entirely above the aeration bench and wicking basket so I will be able to simply yank the old tomato plant out with the majority of the roots attached, then trowel in one cubic foot of replacement potting mix for the next season.

[dice]

Note: The warmer your climate, the faster organic matter
breaks down to silt. Peat moss, coir, and rice hulls all break
down fairly slowly, 5 years at least, even in warm climates.
They are simply difficult for soil microorganisms to digest.
Manure, compost, and leaf mold break down more quickly
to finer particles (and probably support higher populations
of beneficial soil organisms because of their intrinsic
nutritional value to these organisms). Bark fines are
somewhere in between, and straw likely breaks down
at a rate equivalent to leaf mold.

[z-man]

Just wanted to say THANK YOU BOTH for your replys. Lots of food for thought. Z-man