I use plastic containers and drill 1/8 inch diameter holes in the bottom and sides.
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approximately 300 holes. I chose a light color pot so it would not bake the roots in the summer. The shape chosen is because it was free and has a handle. I also drilled 300+ holes around the side on the lower half. In the heat of summer packaging tape can be used to cover over the side holes. Boosting the pot off the ground allows air in the bottom and keeps ants out ( some what ). It also allows for better drainage and prevent the roots from going into the ground. You don't really want to air prune your roots. Any root pruning should be done by your choice and not what happens outside heat when the tree needs them most

Check out the link below for what I have done. Lots of pictures with short writings. My trees are from seed but that does not matter. The indoor lighting will not apply to what you are doing.

Steve

Here is a link that might be useful: http://forums.gardenweb.com/forums/load/citrus/msg101613462758.html

Thanks for the response poncirusguy, lol I have read your post a couple times already, some good ideas. I am just amazed on how little of response I get on my questions on here, regardless if it is container forum, citrus forum, or whatever forum. I do appreciate you advice, being new at citrus I read every night about different mixes, light requirements etc. I work as a manufacturing eng. and rely on multiple resource groups to meet project criteria, asking questions of the experienced experts along with study is fast education, and provides the ability to get off on right foot. Thanks again

The biggest problems you'll run into is the soil drying then not taking water even though you give it a lot. Once the mixes dry out surface tension prevent the water from re-wetting and large sections of roots die and the plant looks sick. I have to place my trees in tubs of water every 2 weeks in the cooler/cold season. in the warm season I can just water frequently enough and not risk root rot problems.

In the winter plant munching insects have no predators. I have to spray all winter starting as soon as the plants come in. After 3 months I start getting over run anyway. Be prepared.

Citrus are usually underfed. They need a lot of nitrogen. What I have listed on my link works well. There are better ones but they exist down south and are very expensive up north

From what I have seen the citrus forum people respond best for suggesting varieties if ask and especially for problems of insects, disease and unknown problems. I did think you would get better responses than just myself.

Last and very important is to get a variety that is good with lower light levels. Varieties are very different from one another. Some varieties do not do as good in full sun. You have control over too much sun by where you place it. you will not have control over sun in the winter. If you live out west where clouds are unheard of disregard what I just said.

Steve

Stimey mandarins do extremely well in greenhouses . Is your greenhouse placed in a very sunny location , if so you can pretty well grow anything you want. I take it you will be placing them outside for the summer ? It basically comes down to if you want fruit or a nice ornamental with nice smelling flowers. If you want good sized fruit the tree will have to be fairly large 4 to 8 ft . Growing citrus in greenhouses is a lot easier than trying to grow them in a house . As far as repotting time the tree will pretty well tell you when it wants to be repotted either by growth decline or massive roots around the surface of the soil . It is you that control the size of the tree because these trees can grow vey rapidly given the right conditions. If you keep up sizing the pot the larger the tree will become. If you want to keep the tree small and healthy ya you can root prune and keep them in the same pot not to hard to do. Gardening is a real full time job especially in the summer so if you go away lots eg cottage vacations you will need to rely on someone to water . Citrus trees need to be watered and fertilized regularly in the summer which brings me to my next point. Some people might put them in a soil that holds more moisture because they go away a lot personally I would not recommend that because you will have to bring them in to the greenhouse in the winter and then you will come in to watering problems because they don't drink as much in the winter and it is very humid in there and you will probably end up over watering. I would recommend either speaking to someone in a reputable garden center about good draining potting soil or reading other garden members recommandations for soil .Citrus do love terra cotta pots . Less chance of over watering but you will have to water them more often than them being in plastic pots. Terra cotta I would recommend only when the plants are smaller only because of weight issues . Terra cotta is a lot harder to move back and forth do to their weight. How would you use a grow bag are you planning to place the bag in the pot ? Greenhouse gardening is easy and fun give it a whirl. Ps citrus plants do make nice bonsai , I have never tried but I have seen them for sale on occasion . Also I learned this year to never over crowd the greenhouse withplants it will end up a fight for the light and only the strong will survive.

Responses? It's been one day, right?

Anyhow, I wouldn't use a grow bag for a citrus - I'd choose something more durable.

You are exactly right in that root-pruning will maximize the vitality and long-term performance of your citrus. Re-potting - including the root-pruning - could be done every 2 - 3 years, depending upon the size of the container. Citrus are a bit touchy, however, so don't do a heavy root-pruning. Better to prune lightly, more often. Also, if you get the roots in good condition (shape and spread) while the trees are smaller and easier to manage, you won't have as much of a struggle when the trees are larger. As the trees grow larger, you can probably go 3 - 5 years between re-potting (if the containers are larger than 10 gallon or so).

Greenhouse will be perfect for your trees.

Josh

orangelime1 My greenhouse is in a sunny location and has good light, I will be moving them outside in the summer, I am looking at using 511 mix I use it now for various plants I believe I am going to modify it a bit to have a little more water retention here in Wichita it is notorious for being hot and dry, we do have our times of humid, but here at my house the containers dry out really fast. I work 10 hrs a day and I do have people at the house that can water for me, but not reliably if it gets hot and dry I need to water twice a day. greenman28 I apologize for being so impatient when I said I am just amazed on how little of response I get to my questions on here, I did use questions as plural, it has only been one day, its another issue that does not pertain to this forum, my statement was unfair. At any rate I believe it is you that has some good info that I have read on root pruning, it really makes sense to root prune to maintain vitality and health. I am looking at just two mandarins I don't recall the variety that I have been looking at, still at the decision stage, I am looking at dwarf variety unless someone can advise me better, I can handle two 20 gallon containers in and out of my greenhouse, more if I didn't have other plants in it. I have some polyester grow bags 24" diameter x 28" tall yes I think they would need to be in another container my door is 32" wide so it would be tight. I have no experience with grow bags, I just put 15 tomato seedlings in some 4" bags to see how they do, Folks I really appreciate your input and knowledge, one last note my greenhouse is heated during the winter months, does citrus grow without dormancy if the temps and light our maintained year round?

Wichita holy hot stuff that will be a lot of watering. I am probably the most furthest northern citrus gardener in this forum and I can go if I am lucky almost a full weekend without watering and that is taking a chance. I leave for the cottage Friday evening I have to be back Sunday afternoon. I have never tried but what about placing your pots in the ground or even your grow bags this way your plants maybe won't dry out as fast and will be more solid in those wicked thunder storms that you probably get in the spring and summer. Even here we can get wicked storms in the summer I can't count how many times I have had to pick up the plants off the ground after a bad storm. That is why I will never use terra cotta I have had a few break. So I would definitely try to plant your trees in a fairly sheltered spot away from wind. I believe citrus go semi dormant with temperatures below 55 . If you keep your greenhouse warmer then that in the winter that will be great for ripening some real sweat fruit. I don't think you will have much problem of keeping your greenhouse at 55 and above with the Wichita sun.

Brian

I meant sweet fruit. I really need to check my spelling before posting. Lol.

I just lost my complete message, I hate that! Here it goes again, yes I think putting the containers in the ground is very valid, I keep a minimum of 55 in the greenhouse during winter, summer in there is a solar furnace I don't even try to keep anything in there, I keep a lot of tropical s that get moved to what I call the pond garden, due to the shade and misting in that area it is close to a tropical zone, there is an area that gets direct sun for the majority of the day, the ground here is virtually beach sand, 3 feet down it is sugar sand, in July I have seen it bone dry at 4 feet, soil temp at the depth has been 80 degrees very alkaline soil. I have considered gritty mix in order to make it easier for pruning greenman28 please advice if it really matters what mix I go with, anxiety has been a life long battle with me so I am trying not to go to fast getting started, I was wanting to order some trees in April or May, but can wait until I feel comfortable with my set up. If I am going to do root work then the longevity of the mix is not a huge issue until they become more mature. Correct me if I am wrong, will 511 go 3 years? I am seeing it start to break down in 2 years but not real bad, I have been studying root pruning every time I see some article, is the bonsai forum a good source for study of is that not applicable for the roots on citrus?

fantastic garden. It is bigger than my yard so I do most of my growing on top of my roof 42 feet above the street.

Kumquat trees on their roots make excellent bonsai. Their roots are very slow growing and do very well in tight quarters. My two kumquat trees will be nothing more than bonsai's. plant many seeds and use the 511 mix. water from underneath and use rooting hormone to keep the trunk from rotting at the soil surface for the first year.

This is about all she will do
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meiwa kumquat bush from seed at 22 months old

link below shows roof top garden. There may be some ideas useful for you. click to enlarge thumb nail.

Here is a link that might be useful: https://plus.google.com/photos/111099372377958308731/albums/5864651368775846321?banner=pwa&authkey=CI763rvAj8eLAg

Rooftop? are you kidding poncirusguy? LOL that is so cool, where do you get the energy? The pics are amazing! so cool, myself I kind of leaned towards the kumquat to start with isn't there a variety that is hardy to 6a? the grand kids just love the cuties so grandpa does also, I have been working on success with alpine strawberry's, not doing real well yet but when the kids are at the house they clean up on the ones that I do have so it has been fun doing the strawberry's. I think I would do some kumquats in the ground if I could find a hardy variety, I need to look more I have been so focused on mandarins, I have an 8 tree orchard of apples, peaches, cherrys, and pears that has been really fun, one of my peach trees came from wally world I know don't do that but, it was almost dead and 75% off lol 4 yrs later it produces the best peaches I have ever had if I don't get a late freeze, it was suppose to be semi dwarf, late bloom, not a chance this tree is going to be huge it has outgrown my other semi dwarfs hands down. Thanks for all the help on my mandarin project

Hi ,Thanks for the compliment. As for the rooftop I have been carrying the rooted leaf duff for 15 years. It is light when dry and holds roots well. Not as much weight as you think.

As far as 6a, poncirus trifoliata is the only one reliable enough to get to that cold. However you can grow some of the hardiest satsuma as a low wide spread bush in a pancake fashion, These forms of bushes are very easy to tent over but you will still have to heat it. A greenhouse is needed for any ease of growing.

Unfortunately you are to far south for alpine strawberries with any real success.

The fruit trees you describe are the one suited for you area and are probably what you want to spend your resorces on. I have the same.--Pears, apples, peaches (from seed), sour cherries from seed, kiwis, figs (hardy chicago), sweet cherries, grapes, paw paws, persimmons, nanking bush cherries All of these trees are 0-spray.

Tent caterpillars = propane gas hand torch taped to 10 ft steel conduit (organic)

Citrus is so cheap. you might not want to waste to much energy on potted trees expecting loads of fruit. Keep- it hobby and enjoy the fruit you get.

Check the link below for potted citrus productivity around the world

Here is a link that might be useful: http://forums.gardenweb.com/forums/load/citrus/msg081305578468.html