I do this with my Plumerias and was wondering if it would work for citrus as well. Would it be possible bury the pot throughout the summer to keep the roots cooler? Would it also be possible to leave said pot in the ground year round IF protection were provided during the winter? This would be in the 6b/7a zone. So far our lowest temp will be 14°F tomorrow night.

The soil here is a clay mix that only good for growing "headaches/backaches". Would this mix keep the water from draining? I have done perk tests on the proposed areas and the water drains within 15 or 20 minutes, but the resulting mud is a slippery, slimy, wet, mess. If we get several inches or days worth of rain it may take a week for the ground to dry. The water will drain away but the above mess is what remains. Also, if we get a heavy rain in short duration, the water will "bounce" and not penetrate more than an inch or so.

I must raise the Plumeria pots from the ground in the fall, as they won't survive anything lower than 40°F, but it does make them much happier with the heat on the plants and the roots kept a bit cooler. I should get flowers this year if the inflos stick around.
Andi

Andi,
If a hail is coming you should be able to dig it out fast...
However, you gave me interesting thoughts:
Hardiness zone here fluctuates from 6 to even 9a (this winter so far)...
link

Having a (hardy) citrus in the pot inground, warm winters included, is viable idea to me...
Putting some gravel (I hope it's correct word) below the pot should enhance draining.
When realy nasty weather comes pots could be raised and moved to a shelter...
Imagine peoples faces looking at 'inground' citrus here ...what a fun ...until a first mistake ...

Hi Andi,
When I lived in NC we had very heavy clay that could be turned directly into pottery or bricks. If you just dug a hole for plants, the hole would fill up with water and kill the plant, but I had a little bit of slope on the side of my yard, so I dug a trench across the back of my lot and filled the trench with good draining material so that one end was open to the lower side. It worked great!

I am thinking about building a styrofoam box (no bottom) with covers to go between the plants to put my seedling pots in during the summer. You can get 4x8 sheets of styrofoam cheap and just tape it together.

The area I was planning to try this experiment is on a slope. The slope is approximately 20°. The trench idea would work IF my leach field wasn't in the way. I really hate to disturb the ground around the leach field. That would entail spending some major bucks if it started to fail because of this. I can dig a hole and put a good layer of washed gravel in the bottom. This should alleviate the drainage problem. As for hail, well lets hope we don't get any.
Andi

Without a wide area dug around and under the in ground container, your tree's root system will suffer from a lake effect that will develop at the bottom of the hole with every rain. Shortly after a containerized tree is placed in a hole the roots will begin to grow into the surrounding soil. When you remove the tree in the fall the new root growth will have to be severed, causing the additional new foliage growth to be out of balance with the root system. They actually manufacture an in ground container "holding sleeve" that is placed permanently in the ground, fit to hold containerized trees. Using a ground sleeve it enables you to remove and replace a tree under the soil's surface in a matter of a seconds. - Millet

Thanks Millet,
Can you tell me what this "holding sleeve" is called and where I can get one? This sounds like the ideal solution to my problem.

You can get them at RootMaker Inc. = http://www.rootmaker.com/rmprod.php
Look down at the bottom of the page. RootMaker might have a minimum order. Another thing you could do is purchase a deep (8-gallon) tree pot which are 11 inches wide X 24 inches deep. Put the tree pot in the ground as a permanent grounder, then fill the bottom with gravel up to a level that allows your tree's container to set at ground level. This would give the tree's root system good drainage. You can see the Tree Pots at Stuewe & Sons, Inc. There web site is www.stuewe.com Stuewe, has no minimum order. You can order as little as one container.
Millet

Thanks Millet,
The tree pots I can get for free as the landscape places here throw them away. I have several collected of various sizes. My Plumerias are planted in 20 gallon pots that I got this way. The gravel I get for free(excluding the gas to go get it) from the gravel pit close to my mothers house. They even wash it for me . I think I should be all set to try this little experiment as soon as the weather warms up and the snow stops.
Andi

Andi, I will vouch for Millet's tall tree plant pots. He sent me some to try & I'hv ordered from Stuewe twice now for their tall tree pots. They are great for getting good root systems. I need to order again.

The landscape businesses here throw them away so I get them for free. You might check with some of the landscape places there and see if you can do the same. The pots I am getting look very similar to the tree pots on the Stuewe website so they should work.