Rooting Observation

[PasturedFigs]

Most successful rooting season I've ever had and I think I owe a great deal of thanks to perlite and those who swore by it. Started with sphag in the bag until some root nubs developed, then cupped up into clear deli containers. The first few that were ready received just MG Perlite that I had screened to remove the dust. Subsequent cuppings used a larger grain, #3, that I picked up in bulk from a hydro shop. The cups with the larger grain had a few bits of sphagnum interspersed along the edges. All the cuttings are looking fairly healthy - but some of the ones in the MG cups are showing black on some of the tips. Compare to the same varieties sitting in larger perlite in the other picture - no tip burn. Is this moisture related? Do the smaller grains compact and retain moisture around the cutting more readily, causing rot at the leaf tips? The larger grain cups certainly do drain better. All cups are in the same humidity bin at a constant temperature and equal access to light. All cups have received equal amounts of water and have not been watered in a few days. All cups are pushing roots to the glass. With these observations, I'm glad the ones affected are in the minority as most got the bulk stuff. Check out the pics - maybe someone can explain the fig science I'm witnessing?

Thanks all,

Kyle

[figpig]

The root system in the smaller perlite look better to me. The larger perlite roots look black at the ends.

[hoosierbanana]

Miracle Grow sneaks fertilizer into everything, black leaf edges are usually a sign of too much fert. Without watering (assumed because you say they are in a humidity bin) the concentration of fertilizer will increase as water evaporates and make trouble.

[AscPete]

Kyle,
It may be moisture related due to the humidity bin and tender leaves. Are you using any fertilizer?.
I've used MG All purpose @ 1/4 - 1/2 teaspoon per Gallon of water to fertigate newly rooted cuttings and have not experienced any fertilizer burn on leaves, MG Perlite has much less fertilizer.

Yes, The smaller particles of Perlite will hold more water (increased perlite surface area / soil porosity / finer particles)

[hoosierbanana]

Have you used MG with only perlite? It has a very low cation exchange capacity and that is why I think the concentration could be too high.

[hoosierbanana]

I will disagree with myself, now remembering that blackened tips due to excess fertilizer occur on older leaves.

[AscPete]

I use MG with 100% perlite only for rooting summer (green) cuttings.
For dormant cuttings with top watering I much prefer a 1-1-1-1/2 mix, PineBark - Coir - Perlite - Calcined Clay all sifted through a window screen sized sieve to remove the fines.

[COGardener]

I had the exact same problem with tips turning black then rotting. Those cutting are also in pure perlite, not watering at all, and then black tips and rot. When really started looking at the humidity bin, I noticed that the humidistat was over 100% and everything in the container was completely covered with condensation. When I vented the bins, the humidity leveled out, the black tips got better, the tips that were rotting stopped. Now all of the cutting are re-growing and thriving, some have even been moved from the humidity bins out to the greenhouse and seen to be loving life.

[PasturedFigs]

This black tip thing is a minor irritation as it seems as all are still putting out strong shoots and roots. I'm certain they'll all overcome it and am thinking the humidity may be the issue like Pete and Scott suggested. I will air out the bin more and see if those few affected improve. Wonder why just a few of those MG ones turned black and others not at all? The fertilizer burn theory is interesting - but besides what MG put in the bag, I haven't used any. Could there be a correlation there too?

[Coop]

I am doing a side by side comparison this year with 100% soaked standard Home Depot perlite un screaned
One tub ( Ikea with clear top) has bottom heat (hydrofarm mat) and the other doesnt.
Both are slightly raised on a rack with a small amount of water on the bottom
Each go 14 hours with 2 x 4' florescent lights with "aquarium/plant light bulbs".
After 1 month 23 out of 24 are still going (the other I am experimenting with into soil when a leaf showed-Negronne)
I think the majority of the unheated tub has done better so far. This is not to discount the heated tub. Some of those have done better than the unheated guys.
Conclusion.... Not sure yet.
Ill report in another month, I'm trying to see if bottom heat is better than no heat

[AscPete]

Light is not necessary for rooting dormant cuttings!
I start my cuttings in the dark where they stay for 2 - 4 weeks.
Warm moist air is really all thats needed in the early stages of rooting and if you rehydrate the cuttings for 2 - 3 days they will root faster.... Try the hydration as part of an experiment.

[AscPete]

Coop,
Glad to have you here....
Coir Potting mix may be the best material for pre-rooting fig cuttings... it can hold the right amount of Moisture, Air and starts off at the correct pH (5-6). The only thing missing a warm dark space : )

[ako1974]

Coop - what do you mean by "23 out of 24 are still going"? Does that mean 1 has rooted, or the reverse?

I'm using heat mats, too, this year, and it seems to be working. But I'm doing a few things differently than last year, so I probably can't yet say it's due to the heat mats. Similar thing, though: Home Depot perlite, clear plastic cups, long shallow plastic bins that go under the bed, cookie racks, and heat mats. I have shop lights that I leave on for 16 hours. The cups dry out - or require - watering probably twice/week. So far, more than half have rooted in under 6 weeks (including that Sal's Corleone you gave me, as of last night ). Most of the un-rooted sticks have leaves or buds swelling.

[Coop]

Hi Arne
Yes, 23 out of the 24 have rooted and the other one I put into some ProMix as an experiment as the leaves were growing without seeing much rooting. It was a slow day and I was antsy. It is still growing. Happy to hear about Sal's C
Pete,
The lighting was part of the experiment too. I agree that they don't need light to root as I do much rooting in the dark with coir. I will try the experiment another time without lights.
I am so happy to hear from you professor

[hoosierbanana]

A likely explanation is calcium deficiency, MG does not supply calcium. Calcium is very immobile and becomes even more so when humidity levels are high because transpiration is reduced, resulting in less calcium being delivered to growth. Here is calcium deficiency (tip burn) on strawberry. Calcium can be given to the plant with a foliar sprays, such as CA MG +.