the person who renovated the house before we bought it went a bit nuts with the construction of the driveway, and left me with a huge expanse of bright white concrete. I intend to make use of this by putting some figs and other plants in containers heeled into soil on top of the concrete, and in containers large enough so that they need to be rolled around. My questions is this - for the larger containers, which will be on casters, what are some design considerations that I should keep in mind when building them? All suggestions welcome, and I'll post photos of what I come up with for further comment, derisive hoots, etc. 

i figure rolling them into the greenhouses and garage will be a heck of load off my back, rather than dragging them.

Joe

If using casters make sure your media is light, a heavy media a little water then The casters will break off standard pots. I have a grain bag hand truck with a large foot that slides under the pot base and then I just wheel them wherever.. Bought it at farm auction for fifteen dollars.Or plan b was to weld a larger base onto a standard handtruck.

Plan C was to purchase a plastic sled and slide the pots ontop of the sled then just pull into the garage.. I have one for hunting and it is a life saver for dragging deer off the mountain...

Sorry, probably wasn't being clear - I'm actually going to build some containers in which the soil will go. I'm thinking this way I can build them somewhat larger than the standard (and rather expensive) larger pots. One option is to use recycled plastic lumber, which is now sold at Home Depot and is comparable in price with standard hi grade 2 X4s, can be routed, etc. My idea is to be able to roll them out into the concrete- covered "yard" and then right back into the garage should it become sufficiently cold to cause injury to the plants.

What volumes should I shoot for for the varieties that you people have been growing in containers?
Joe

Joe,

I use tree size as a guide for my container size.  I know many forum members like to use over-sized containers.  To my mind, that is a waste of growing mix.  I use a mix of fine pine bark, expanded shale and Perlite.  I find the pine bark's life is realistically 2 years and, if pushed, 3 years at best.  So here my potting schedule is roughly this:

Rooted cuttings go into a .3g container for about 3 months.  They are potted up to a 3.4g (1/2 cu ft) container for the remainder of 2 years (If the tree trunk isn't close to 1" in diameter after 2 years, it stays for another year).  From there, the tree goes into a 12g (~2 cu ft) container for 2-3 years (until about 2-2.5" in diameter).  Afterward, they go into larger containers.  Right now, I have two trees with 4" + Diameter trunks in ~25g (~4 cu ft) containers.  The containers is way too small for these trees.  A more appropriate size would be 60-100g (10-15 cu ft). 

Of course, you'll want to develop a repotting schedule of your own.  The size of the container can easily be tied to trunk diameter.

As for designs, a couple of ideas come to mind.  Here is a picture of the set up I have in Houston:

Initially I had planned to put large casters on the trays so they could be easily moved for mowing purposes.  Instead, I doubled up the cinder blocks so the lawn mower would fit underneath.  However, the design could easily be fortified to withstand being moved on casters. 

If the goal is to have a stand alone container on wheels, you could build a base on casters then attach the Rootmaker RootBuilder (or other plastic wall) to it. 

If it were me and I had the space, I would use the 18" high walls rather than the 30" high.  For a 60g container, you would want a container that is about 18" H X 33" D.  If you wanted to go larger, a 100g container would be about 18" H X 42" D.

~james

Thanks James, very interesting ideas. Also intrigued by your soil mix. Do you think that it would work well for the Southwest?

Joe

Here is another unique fig container by Bill's Figs.
These are the (expensive) self-watering kind.
Recently I bought a couple  just to try them out.
http://figs4funforum.websitetoolbox.com/post?id=3525293&highlight=bills+figs

Having said that, I tend to grow my figs in simple 5 gallon buckets, with
drain holes at the bottom vertical side, 1/4 bury them in summer for the
roots to graze, and then winter-store them in my unheated garage. 

It depends on how often you are willing to water your containers.  The mix drains pretty quickly.  In Houston, during the heat of the summer, the containers need daily watering.  The 3g containers require 3/4-1g of water per day.  The 25g need 5-7 gallons.  After three days the mix is hydrophobic and needs to be re-wet before watering.  The smaller the container, the more critical it is to adhere to a schedule.

I mentioned my mix mostly as a guide as to how long to expect growing mixes to last, not necessarily as a suggestion as to what to use.  Usually many compromises need to be made in determining container size and growing mix.

~james

Anybody use any sort of an automatic watering system, drip, etc.? It's so dry here in Albuquerque and there are times when I'm working out of town...

Joe

I have been dreaming/designing a 'drip' watering system  for quite a while.
HECK, once that is accomplished, I then can take a one-more/good (last?) vacation....

Gorgi, let me know what your ideas are up to this point.

Joe

Here is my simple drip system i found myself in a pickle last year. I use 3gph on large pots and 1gph emitters on small. time varies depending on what time of year. 

I  think the easiest way for the average grower is to bury 1/3 of the pot in the ground. I agree with George. The tree grows more vigorously and needs less watering once the roots penetrated out. 

drip is the only way to go.  i have a very extensive drip system with 8 zones.  luckily for me, i have a great well, so i can water away :)