The Science or "Why" Behind Rooting Cuttings

[ross]

Hello everyone,

I've been seeing a lot of threads lately on rooting cuttings (it's that time of the year), but I haven't found a single one (even in the past as far as I could tell) that describes the science behind it. We have all these methods listed describing how & when to root cuttings, but nothing describing the why. Understanding that I think will alleviate a lot of problems and common questions.

Rooting cuttings have totally difference needs than what most of us inexperienced rooters are used to. What I'm saying is.. we all have pretty good green thumbs (otherwise we probably wouldn't be on this forum), but you need a different kind of green thumb to root cuttings. Here's what I've gathered and hopefully someone can explain why in greater detail.

Differences between cuttings vs young to established fig trees:

1. Cuttings require a large amount of humidity.
2. Optimal rooting temperatures are between 70-80 degrees.
3. Cuttings do not need large amounts of light until leaves form. In fact, unnecessary light can actually dry out the cuttings?
4. Initially lightly water to help create humidity. Only when roots/leaves form it might be time to lightly water again since the initial watering.
5. Mold can be a serious issue & kill cuttings much more quickly than an established plant.
6. Light & airy soil mediums must be a priority for underdeveloped root systems.

Common pitfalls of rooting cuttings:

1. Mold.
2. Overwatering.
3. Not having enough patience when potting up or destroying roots when potting up.
4. Allowing cuttings to dry out.


I'll be updating these two lists as more information becomes available. If any of this is incorrect please let me know. I'm certainly no expert on rooting cuttings. Thanks!

-Ross

[smithmal]

Great thread. I might also add that another pitfall (as I did this myself last year) is to fertilize your cuttings to early. I fertilized my up potted cuttings and killed 95% of them. This year the only type of fertilizer that I will be using after up potting and allowing the cutting to establish itself is some rabbit poo I got from a friend. Next Spring I'll use a continual time release fert like Osmocote.

[AscPete]

As soon as roots develop...
But I also hydrate my rooting medium (Coir) with a dilute fertilizer solution Miracle-Gro @ 1/2 teaspoon / gallon of water, http://figs4funforum.websitetoolbox....ht=fertigation

[jmaler]

I am with Pete on dilute liquid fert early on. My idea with this came with growing african violets using the wicking method in soil less growing medium. The recommended dose was 1/4 tsp per gal which is what I start my fig cuttings on. As the plant grows I increase the strength accordingly not to exceed 1 TBS per gal for established 1 gal size & up.

[ross]

Interesting info! I'd have never thought of that.

[AscPete]

Hello Ross,

IMO, Understanding the why's of Auxins and Cytokins and cellular differentiation is not necessary nor essential, http://aggie-horticulture.tamu.edu/s...agation-02.pdf only a basic understanding of how and what cuttings need for successfully rooting and growing them.

Your compilation of the requirements for rooting cuttings is complete and is only missing a plan for creating the "stages" of rooting as described in this article, http://www.flor.hrt.msu.edu/assets/U...esplanning.pdf .

Establish propagation stages.
During propagation, cuttings transition from a completely rootless stem to an actively growing plant. Similar to seedling plugs, cuttings should be managed differently as root development progresses.

As cuttings develop roots, they need to be weaned off conditions for lush growth. Misting frequency should be reduced and light levels can be increased. Once roots have filled up half of the plug cell, the humidity can be reduced, misting can be terminated and fertility levels can increase. During the last several days of propagation, plants that are hardened off will perform better after transplant.

Providing different conditions during the propagation phases can shorten total propagation time and produce high quality, rooted transplants.

The article is applicable to rooting dormant fig cuttings although its generic procedures apply to rooting green cuttings.

The Fig Propagation phases/stages for dormant cuttings:
1 - Pre rooting / Hydration (high ambient Humidity @ cutting)
2 - Rooting (high to normal ambient Humidity @ cutting)
3 - Growing out (normal ambient humidity @ cutting with light)
4 - transplanting
Good Luck.

[ross]

Definitely a good article, Pete. There's a lot to understand here. As for the science, I unfortunately didn't get much out of that, haha.

[Rafaelissimmo]

It would seem important to note that some media have anti-microbial properties, like coir and spaghnum moss, that inhibit mold and others like perlite and peat moss, that are inert and somewhat hostile to gnats and other pests. Also, we assume rooting in media, since water rooting, when properly done, can also avoid mold and rot.

[Rewton]

I was going to add fungus gnats to the list of possible pitfalls (although some believe that gnats don't cause a problem but show up once rotting has already started). I've definitely had them show up on rooted cuttings that are growing ok and have usually been able to control them well enough to keep the rooted cutting from dying but using gnatrol.

[AscPete]

Yes, for fungus Gnats, http://www.ipm.ucdavis.edu/PDF/PESTN...ungusgnats.pdf treatment with Gnatrol or Mosquito dunks has proven effective, but starting out with clean or sterile potting material of low pH values without 'Organic' fertilizers has been most effective in reducing Bacteria, Mold and Insects in the rooting medium.

[smithmal]

AscPete,

What in your opinion is the best non-organic fertilizer to use? I had a bad gnat problem last year and dried the mosquito dunk tanks to no avail. I was considering covering the surface of the growing media with saran wrap between waterings. It's my understanding its the moist surface of the media where the gnats lay their eggs and proliferate.

[AscPete]

Malcolm,

Any complete balanced water Soluble Fertilizer will work to provide the required macro and micro nutrients, http://www.mgofmc.org/docs/nutrientdeficiency.pdf . I've used Dilute water soluble Miracle-Gro, General Hydroponics and Peters fertilizers, http://figs4funforum.websitetoolbox....ht=fertigation . The General Hydroponics Maxi-Grow and Maxi-Bloom are a little pricey, but are 100% complete and have worked well for fig cuttings in hydroponic solutions and potting medium.