Effect of Kelp Extract on New Growths

[Mapp]

Hi there,

After a long period of being plantless (for various reasons), I've decided to get back into orchids. This current attempt I'm taking a bit more seriously than the last and while I'm climbing my way back up the learning curve I have quite a few questions.

Many of the questions I have will simply have to be answered through experience, and others have been discussed extensively and will just require a bit of reading on my part—I'll try to avoid cluttering the forum with those

One think I am wondering about that I haven't been able to find any information on is the effect of kelp extract (particularly auxin-heavy formulations, like Kelpmax) on new, emerging growths. Auxins (to my understanding) induce new root growth and promote branching of the existing root system, but they also have the effect of suppressing vegetative growth.

I have a mini-cattleya with two new growths. One is quite advanced and is just starting to put out new roots while the other is about two months behind it and still a relatively small nubbin. I've had huge success with using Kelpmax on another, basically rootless cattleya and I figure it would be wise to use it on this one just as the new roots emerge to 'help it along', so to speak. However, I'm concerned about the auxins stunting the newer growth in favor of producing new roots. Does this class of hormones have any effect on existing, already growing shoots, or is it more a regulator of when dormant eyes will start to sprout?

Thanks for your time and apologies for the paragraphs,

Matt

[SaraJean]

I think that malformations of growths or flowers has to do with concentration and/or frequency. Too much of a good thing and all that... So how often are you using it and at what dose?

[Mapp]

The only times I've used it were after repotting plants that had poor root systems, using it at a 1:250 ratio for about a week and a half/2-3 waterings as per the label. I don't use it as a regular additive the way I would, say, fertilizer. Less is more, as they say. I'd likely only use it in a single watering for this plant as it's fairly well established.

[camille1585]

You are mostly correct about the effect of the hormones, but to have such suppression of leafy growth while using seaweed extract /kelpmax, you would need to be using it frequently I would think, and also forgetting a few aspects of hormone 'behavior'.

Auxin is naturally produced in the tops of the plant, in the meristems (growth tip) and effectively blocks lateral growth for instance, and flow down the plant to trigger root development. This is the effect kelp products somewhat mimic/enhance. Then the opposite happens with the developing roots, which produce cytokinins with flow upwards in the plant and encourage above ground growth. So it's a sort of perpetual feedback loop.

Applying kelp products one or a couple times will effectively boost root growth, but then you have to consider two things in my view: one is that once you stop applying the product, hormone ratios return to normal, and the newly produced roots with be producing lots of cytokinins. Second is that strong healthy roots will be able to support strong healthy growths, so in the long run it's a win-win situation.

Have a look at Ray's information sheet on Kelpmax if you haven't done so already. KelpMax Kelp Extract >> First Rays LLC

[Ray]

Originally Posted by Mapp

Auxins (to my understanding) induce new root growth and promote branching of the existing root system, but they also have the effect of suppressing vegetative growth.

Auxins, when poperly applied, do not suppress shoot growth.

Expanding on Camille's description, as plants grow the shoot apical meristem produces auxins that flow down through the plant, stimulating root growth and branching. As roots grow, their apical meristematic tissues produce cytokinins that flow up through the plant, stimulating shoot growth and branching.

When you apply a kelp extract (and they are far from being all the same), depending upon the specific product, either roots or shoots are stimulated into accelerated growth, then the natural response follows, albeit at a somewhat reduced rate, going back-and-forth, deminishing in concentration at each cycle over about a 2-3 week period, until it subsides back to its normal rates.

If the kelp extract is higher in cytokinins than auxins (typical of those based upon Ascophyllum nodosum), while both still happen, shoot growth is typically accelerated more than that of roots, leading to leggy plants.

[isurus79]

Originally Posted by Ray

If the kelp extract is higher in cytokinins than auxins (typical of those based upon Ascophyllum nodosum), while both still happen, shoot growth is typically accelerated more than that of roots, leading to leggy plants.

I did not realize this. Good info!

Glad I got KelpMax this year!

[Mapp]

Thank you Camille and Ray for the informative replies! I was aware of the auxin-cytokinin hormone cycle but I wasn't sure how severely it was effected by kelp-based supplements. I'll use as directed on the label, although I guess that should've been the obvious choice from the get-go. I do like hearing the reasoning behind why I should be doing something, though.

Thanks again for taking the time to reply