Rooting Hormones - the good and bad

[Ray]

Indole butyric acid (IBA) and naphthalene acetic acid (NAA) are synthetic root stimulants. One of them is particularly well-suited to initiating new root growth (NAA, if I recall correctly), while the other promotes continued growth of existing roots. Vitamin B1 (thiamine) is also a known root-growth stimulant. They are not fertilizers.

K-L-N contains both hormones (about 0.1% each) and B1 (0.025%). SuperThrive - among a concoction of other things like kelp extracts, humic acid, etc. - contains B1 (0.09%) and NAA (0.04%).

The hormones are powerful chemicals, which is why they are typically in concentrations below 0.1% in the bottle, and are recommended at a drop or two per gallon in application (0.000002%).

They also tend to work by "instantaneous exposure". Think of a light switch - once you apply the energy and flip the lever up, continuing to push on it does not make the light glow brighter. Once the cells get "turned on", adding more hormone does not accelerate them (it might turn on more cells, though, if you didn't get a good treatment the first time).

I have first-hand experience that applying them too heavily can have negative effects: Many years ago, I developed my own formulation that testing showed was superior to both K-L-N and ST. As a further experiment, I started increasing the dosage. After an extended period of the equivalent to 1 teaspoon per gallon, all of my phalaenopsis flowers were deformed as they came into bloom. It was, fortunately, reversible.

I have heard from another grower that plant growth was stunted with such a large exposure as well, but I do not recall seeing that.

Another thing to keep in mind about the hormones: they are very unstable, degrading very quickly upon exposure to sunlight and heat. If you keep a bottle at household temperatures, they will be relatively ineffective in a matter of a few months. A refrigerator can extend the life to a year or so.

My personal "take" on their use is that if your orchid culture is good, using them doesn't add a great deal. If, on the other hand, your culture is lacking and the root systems are suffering, they can be beneficial.

[gixrj18]

[Cookiemonster]

Originally Posted by Ray

Indole butyric acid (IBA) and naphthalene acetic acid (NAA) are synthetic root stimulants. One of them is particularly well-suited to initiating new root growth (NAA, if I recall correctly), while the other promotes continued growth of existing roots. Vitamin B1 (thiamine) is also a known root-growth stimulant. They are not fertilizers.

K-L-N contains both hormones (about 0.1% each) and B1 (0.025%). SuperThrive - among a concoction of other things like kelp extracts, humic acid, etc. - contains B1 (0.09%) and NAA (0.04%).

The hormones are powerful chemicals, which is why they are typically in concentrations below 0.1% in the bottle, and are recommended at a drop or two per gallon in application (0.000002%).

They also tend to work by "instantaneous exposure". Think of a light switch - once you apply the energy and flip the lever up, continuing to push on it does not make the light glow brighter. Once the cells get "turned on", adding more hormone does not accelerate them (it might turn on more cells, though, if you didn't get a good treatment the first time).

I have first-hand experience that applying them too heavily can have negative effects: Many years ago, I developed my own formulation that testing showed was superior to both K-L-N and ST. As a further experiment, I started increasing the dosage. After an extended period of the equivalent to 1 teaspoon per gallon, all of my phalaenopsis flowers were deformed as they came into bloom. It was, fortunately, reversible.

I have heard from another grower that plant growth was stunted with such a large exposure as well, but I do not recall seeing that.

Another thing to keep in mind about the hormones: they are very unstable, degrading very quickly upon exposure to sunlight and heat. If you keep a bottle at household temperatures, they will be relatively ineffective in a matter of a few months. A refrigerator can extend the life to a year or so.

My personal "take" on their use is that if your orchid culture is good, using them doesn't add a great deal. If, on the other hand, your culture is lacking and the root systems are suffering, they can be beneficial.

Second everything Ray said- especially
"if your orchid culture is good, using them doesn't add a great deal. If, on the other hand, your culture is lacking and the root systems are suffering, they can be beneficial."

For people with less than ideal growing conditions rooting hormone can make a big difference, if you've got great conditions you dont really need them, but would give you a superboost I'd think in very minimal quantities !!

[RosieC]

Thanks for the great info Ray