I've seen a couple of questions on up-potting on the forum over the last couple of months, and I've chatted back and forth with folks with questions also. 

Thing is, I can't seem to find a dedicated thread on up-potting, so I figured maybe it was time to start one.

In my area (Southeast USA), I don't personally feel like there is a bad time to up-pot trees.  I think if you are careful about how you up-pot, you can be successful year-round.  I personally prefer to up-pot in middle of spring or late summer so my trees have at least 1-2 months of warm weather to work on root growth before experiencing intense heat or intense cold. 

In my area, I've not had any losses from up-potting in the middle of summer as long as I am careful about how much the root ball is disturbed, I keep my watering in check and I put the plant in full shade for at least a few days before gradually introducing to any significant sun.  I'm up-potting right now, actually....

I think one of the fundamental things anyone needs to understand about repotting - whether it's from cups/bags to pots, or smaller pots to to larger pots - is this: 

With many plants, the roots are a hydraulic pump system that pulls water up to the leaves.  Any time you do something which breaks, damages or otherwise shocks the roots, you hinder a plant's ability to supply water to the leaves.  When water isn't supplied to the leaves as expected, the side effect is droopy leaves.  Droopy leaves are not something to panic about - it should be expected after doing anything that even slightly disturbs your soil moisture or your root ball.

I think it's important to know how to tell when a plant is ready for up-pot.  I like to up-pot when my plant has enough roots that I can easily slide the entire plant out of its pot and the root ball sticks together totally.  I DO NOT want my plant to be "root bound" to any degree.  For example, this is a plant that is root bound - I want to see at least 50% less roots in my pot than what you see in this picture:

Nice illustration of the tightly circling roots, often caused by up-potting a rootbound tree from a small container without first taking corrective action. It's a time bomb--if you buy a fifteen gallon tree with this problem, you'll never know about it until it's too late. 

I wish I would have taken a picture of the roots of the Carolina Dark when I was up-potting.  Hands were dirty.  I have about 35 more trees to up-pot, so ... I am hopeful I will get another chance!

I don't think some folks realize how deadly this condition can be, nor do they know to look for it.  They just see "fat roots" and think "hell yeah!", but it's bad news to not correct it, even knowing the obvious damage that will occur when you start cutting out fat roots.  I think the last three pictures above show the kind of damage you can do, but it beats the hell out of your tree choking itself to death in 5-6 years.

Jason,

After you finish honing you post, I'd like to add it to the FAQ at Figs4 Fun.

I do a couple things differently, but necessarily any better, just my preference.

I like to water real well a couple days before, and then repot just before it is time to water. I find that a dryer rootball comes out of the pot much easier than a wet one.

I have, in the past, also taken a 2" strip of plastic and run it down the inside of the pot, across the bottom, and up the other side, with 3-4" sticking out on each side. This makes a nice handle to help lift it out of the pot.

I repot any time the plant out-growing the pot. I double pot my plants to keep them from rooting into the ground. I will usually have nice roots growing out of the bottom of the inner pot, and into the space between the two pots. If I think it is necessary, I'll put repotted plants in the shade for a few days to reduce stress, but seldom have and real issues. Repotting when dormant is fine, as well.

I also repot late in the day if I think the e=weather warrants. Starting with a cool(er) evening, before the first hot day, I think, gives the plants more recovery time. Putting them in a humid greenhouse is a good option to control moisture loss.

My schedule makes it tough to repot in the evening, but I would prefer that idea.  I will try the 'dry' method of transfer, but have had nothing but good luck with wet.  I want to mark up the bit about time of day for sure.

I also like the idea of the handle.

I personally use plastic bread loaf trays to hold several pots (9-10 @ 1gal, 4-5 @ 3gal), which provide an air gap of 3/4" between the bottom of the pot and the soil.  Freaking plants are still sending roots through the air and into the ground!

Even with double potting, they will eventually root into the ground, but it gives me and opportunity to catch them before it happens, and has the added benefit of letting more roots develop at the bottom, if that is what they are intent on doing.

Jason you have good way with words in your posts and make it easy for folks to follow. It should be put on Jons site.

Im unconventional in how i do things and they work for me so i stick to them. 
For example similar to Jon i do it when soil is somewaht dry but not completely.
I sneak up on plant grab main trunk and lift it right out without anything disturbed.
Does not even know it !
I put in waiting pot and my potting mix and right back in full sun.
Once in its final pot size every 2-3 years depending on plant it gets a good root working over.
Thats a pain and each year im doing some containers.

I dont suggest it to no one and not to be put on Jon's site either.
Just what i do for the curious.

I am fine with this being added to the FAQ, it is probably a decent fit for something like that.

Excellent thread Jason.  Thanks.

I was up-potting yesterday late afternoon. After up-potting & watering, I placed newly up-potted trees in shade for up to 2 weeks. I used composted soil for up-potting. None of my up-potted trees are as root bound as those in pic's posted.
I have up-potted extremely root bound trees from slim & tall pots and they have done very well.

How do you know if the roots are wrapping around the trunk inside the rootball? Do you need to wash away all the potting mix? Or do the roots just all head away from the tree until they hit the pot and then start wrapping? I up potted a few this weekend. They were not as root bound as the one in your picture. I just tried to gently loosen some of the larger roots going around, but basically left the ball intact and just put it in a larger pot.

I could actually see the root close to the soil surface, it was circling one full loop close to the trunk (similar to what's pictured above, not as many loops). 

By pulling on that root, it was clearly affecting a root that was totally circling around the pot wall, and tugging on where that root disappeared into the root ball made the soil move around clear on the other side of the pot, so I know it was criss-crossing through the pot. 

Rather than take any chances, I cut the root out completely.  Overkill?  Probably.  I know it's not going to kill the tree .... better safe than sorry.

jason,

my trees when i pulled them out of 3 g pot was worse than your first picture. it was going around and around at the bottom of the pot. after up potting, i thought about it and i pulled them out again to untangle the roots, but it was so tight, i had to more or less drive scresdriver in there to untangle them.

i didn't see any root going around the trunk itself, but i think i'm going to do some root pruning come spring, and long with pruning for the branches.

pete

One easy way to avoid those self-strangling (circling) roots is,

Thanks for the post Jason. It's time for me to up-pot, but I've been a bit nervous about it. Can you tell us what soil mix you use?

I typically use Fafard products, because that's what my favorite garden center(s) have here in Atlanta - it's either that or Miracle Grow potting mix, and I try to avoid MG products.

I prefer to use Fafard 3B for my smaller trees (1gal or less) mixed with about 15% perlite (1 scoop perlite, 5½ scoops Fafard mix) - it has no slow-release fertilizer, newly rooted trees don't need it, I want to control the fertilizer regimen myself.  

For trees that are larger than 1gal, I typically use Fafard Professional potting mix also mixed down with perlite at the same ratio.  It has a slow release fertilizer that will last up to 4 months, which will usually get me to the next up-potting.

This last go-round, my closest local nursery was out of 3B and no longer carries the Professional potting mix, so I had to get their "Complete container mix" (it was all they had!).  We will see how that goes.

In all honesty, you could probably get away with using dirt right out of the ground, or compost.  I just prefer pre-made mixes because I don't want to mix my own - it's not worth the time, hassle and money to me.

Updated to add pictures of what I "like" to see in my rootball.

I have no plans to update this thread any further.  Feedback welcome.  Otherwise, I'm leaving it as a 'stamp' of one path to follow.

The discussion above seems to focus only on up-potting into the same soil. I decided to revive this thread to ask a question about my situation.   I want to up-pot my RdB from a 1 gallon pot to a 3 gallon.  Currently, the tree is in commercial potting mix, I believe Miracle Gro.  But when I up-pot I want to use one of Al Tapla's mixes.  Given that we are in the middle of summer in a very hot period would it make sense to try to remove the soil from the roots when up-potting?  Or should I play it safe (and not risk injury to the roots) and leave most of the root-ball intact?  As it stands now the tree is doing very well but I want to make sure it stays that way.  Thanks.

Steve

Really shouldn't mess too much during the hot summer months other then lossen a bit with your hands or scoring the outside roots.

But I don't see a problem. The only thing I tried as a planting mix that didn't work was a commercial pot soil,  manure and sand mix. Seemed to not allow enough aeration and nutrients. It was stunted alot. This year I changed it and replanted. Has now taken off.

If you actually want to remove the miracle grow mix when you repot then I would not do that now, in the heat of summer.  Do that when the tree is dormant.  I would just pot it on up in Taplas mix, assuming it is not rootbound. I've been making my own Tapla soil the last 2 years and I've had amazing results.
Good luck,
Eric 

last year, i basically bare root and repot my 3 gal trees into 10 gal. it was in middle of june. it wasn't as hot as now. it took almost a month for the trees regain their perkiness.. if that's a word.

if they are my trees, i won't do that again. i'm planning to repot all my 1 gal plants this fall once the temp is more reasonable, and the night low is above 50 degress. if i get lazy, i'll wait till the spring. right now i'm using 50/50 seedling soil/perlite. when i repot, i'll be using my 5:1:1 mix.

bare rooting the young tree and putting them in new soil mix might stress them out too much. specially with current temp going over high 90s into 100s.

pete

Thanks for all the advice! As per the suggestions, this time I'll up-pot keeping the root ball intact (save for any loose soil).  I'm pretty sure the tree isn't root bound so it's unlikely I will need to do any root pruning though I might score along one side.

Next year when I move up from a 3 gallon to something larger I'll plan on doing a bare-root up-pot (a.k.a. re-pot) when the weather is cooler. 

Steve

Steve,

I have a few general rules when it comes to my containers:

James, hmm that gives me more to think about.  One thing I haven't done is what is shown in the images upthread - pull the plant out of the pot and see what the roots actually look like.  I'll do that this weekend and decide whether to wait until the cooler September weather.

Having read all this info on up potting, is there a more preferred time of year to up pot. I guess the real question is, is this a good  time to up pot?

Now is a great time to up-pot as any, but two notes: 1) i suggest you don't fertilize in process, that may encourage new growth, which is not something you want this close to end of season and 2) you may not want to up-pot of fruiting is in progress, although I haven't had a huge issue with it personally, it's just something to be considerate of.

I intend to up-pot my trees next month, if not, I'll do it in May. Still undecided this far.