This winter I put about 24 cuttings into 1 Qt clear soda bottles that had the tops cut off. I used potting mixture and kept them all in a covered plastic tub in the basement. Watered occasionally and they all budded.

When it got warm enough I put the tub outside for the day, like a small greenhouse. Eventually I kept the cover off and immeduiately about 1/2 had the small leaves shrivel and die. They had no root formation.

I waited for a couple of the others to get bigger leaves but when I went to re-pot, again, no root formation to speak of, the roots were tiny and broke off when I tried to remove them from the soda bottles.

I now have 4 left and they each have about 4-5 nice sized leaves but minimal roots that I can see.

Whatcan I do to encourage root formation so i can re-pot them without tearing the roots off?


thanks,

 Rob

Rob, it sounds like your cuttings had more light (leaf growth) than warmth (root growth) and in your situation, I might leave the 4 survivors in their current containers. They'll probably have to stay as "windowsill plants" for the summer. Just make sure you cover the soda containers with something opaque, like duct tape. Roots don't like light.
You might want to hold off transplanting until they are nice and strong, and root bound, even if it means waiting until they go dormant.
At that point you can dip them in water, unravel the roots as best you can and spread them out. Put them in 1 gallon pots with just slightly moist potting soil, and let them sleep in the dark for the winter.
Next year they'll take off for you.

Sounds like good info to me. I don't know, maybe you are allready doing this, but you need to gradually increase the amount of fresh dry air over time when using a rooting bin/chamber. The gradual increase of dry air stress will promote more root formation, when in saturated air sometimes the plant has no need to grow much for roots. 

I read some of your old posts on Garden Web, how did your trees do after you up-potted to half barrels with gritty mix?

As ruuting said, warmth, preferably bottom heat is great for root development. If you can get a seedling heatmat, those work great

Thanks guys, I think I have a plan. First, cover the bottles with duct tape to give the roots darkeness. Then I'm going to take them out of the bin, which is raised on a small dolly, and put them right down on the driveway asphalt which gets very warm during the day and gives off heat all night, should work, no?

Calvin, those trees with the gritty mixture are due to be repotted this year. They look great, plenty of lush leaves, so much that I pinch them back. I get plenty of figs but only half ever seem to get ripe. I have one tree that usually has 100 fruits on it that are not ripe by the time I have to put them away for the winter. The other two have decent production.  Last year they split open before ripening.



On the plus side, you can't over-water, on the minus side if you go away for the weekend they are stressed when you return.

I have some more trees that are ready to go into the big pots, I think I'll add more pine bark fines to hold water longer.

The asphalt might get too hot for a quart size bottle/pot.
That might cook your roots rather than encourage them to grow.

Think so? It's this type of bottle bottom, only touches on 5 points. I'm going to take the asphalts temp tomorrow, I'll let you know.

Also if you had it in high humidity you need to transition slowly, as Calvin said.  Maybe you already did this. 

A previous post shared some info that the roots like to be at 80F for good growth.  At 90F root growth slows and above that they start to die.  Blacktop on a sunny day in 80-90F weather can get over 130F.

I agree that small containers should not be put on asphalt.  I would actually shade them during this part of the year, when daytime temperatures are usually > 80 anyway.  Put them on the north side of a small shrub, plant, or another pot to still let some sunlight get to the leaves.  Patience is the key here.  Don't take the cuttings out of those containers until you see lots of roots.  No more humidity bins, etc.  At this point the outdoor environment is mostly ideal for cuttings, as long as you keep the root zone shaded. 

I had one very thick cutting that I had in sphagnum moss all winter and spring and it didn't do anything.  Ends started to dry up.  I actually forgot about it, then a few weeks ago, I said, oh crap, what's up with that cutting?  Went down to the basement and there were a lot of roots and shoots.  Stuck it in a 1 gallon pot, and shaded it as I describe above, and it is now taking off.  But I won't be re-potting it until next spring most likely. 

As long as the cutting is not rotten or dried out, there is still plenty of hope, even if you break some roots, and if leaves shrivel and die. 

I've had great luck increasing root growth by inoculating my figs with mycorrhizae. Try watering with a diluted water mycorrhizae mixture. 

The duct tape did it, I had a bundle of roots on one of my plants, came out whole and transplanted nicely.


thanks,

 Rob