The benefits of the use of kelp in horticulture has been known for a very long time. In addition to fish, the Native Americans taught the Pilgrims to till kelp into the soil for better crop growth.
A few decades ago, when kelp products were first offered to the grower, very little was known of their modes of action and many claims were made, some unjustified as well as based on incorrect assumptions. One clear finding was that when applied at specific times and in specific ways, some products triggered physiological responses in crops.
Back then, kelp products suffered from a poor reputation due to their inconsistency and confusing claims. As the decades passed new products were developed and greater science was applied to unlocking the truth behind their applications.
As the science has matured, we have learned that the effects of kelp products can be explained by the presence of a variety of phytochemicals, including hormones, polyamines, polysaccharides, phlorotannins and a multitude of other plant growth regulators. Through those, the kelp application triggers responses on a cellular level
The efficacy of seaweed-based products are quite variable, depending upon the species of kelp used, how they are harvested, and how the active ingredients are extracted from them.
Structurally, kelp is made up of very tough cell walls that are resistant to rupture under sometimes-violent sea action. In order to achieve breakdown of the cells to collect their contents most manufacturers use chemical or heat digestive processes, which leads to rapid degradation of the phytochemicals, resulting in commercial products in which the active ingredients are mostly degraded, rendering them to be more useful as fertilizers than as stimulants. Kelpak concentrate, on the other hand, is produced using a patented high pressure differential technique that results in cellular burst to release the juices, avoiding the use of chemicals, heat, freezing, or dehydration. That ensures that the product retains its potency and has an extended shelf-life. In fact, if kept tightly sealed between uses, cool, and out of sunlight, Kelpak will remine viable for at least two years, which is considerably greater than liquid synthetic hormone products on the market.
So how does it work? The simplest explanation is the analogy of being a “plant I.V.”. Just as a a football player might get an I.V. of electrolytes and vitamins at halftime, enabling him to perform better in the second half, the application of Kelpak gives the plant a large dose of the same phytochemicals it would produce for itself, but by being absorbed from outside sources, it doesn’t have to expend its own resources to produce them, thereby giving it greater resources for growth. That, coupled with the high concentration of plant growth regulators in Kelpak, results in faster growth, including a significant increase in root growth and branching. The increased root volume and number of root tips increases moisture and nutrient uptake, and that, together with the higher levels of natural, internally-produced phytochemicals in the plant, gives stronger top growth, making the plant more resistant to stresses such as drought, waterlogging, nutrient deficiency, or salinity, and some soil borne diseases.
Other seaweed extracts may also stimulate plant growth, but it is primarily in the top growth and not roots, so may lead to plants whose root systems are not developed enough to adequately support them. The result is a bigger, faster-growing plant, but one that can be weaker, and more susceptible to any number of stresses.
If this description isn’t sufficient for you, how about a picture? In the spring, as temperatures warm, we typically see our vandaceous plants begin to sprout new roots, extend existing ones, and then put on a flush of new foliage. Since the addition of Kelpak to our regular fertilizing regimen, we have seen an amazing amount of branching of the roots of all genera.
OK. Now more of the science behind this.
Many of the internal biological processes of plants – just like us – are controlled by hormones. Two of the more important classes of those are auxins and cytokinins. Both play an ongoing role, but let’s start with auxins…
Auxins are naturally produced at the apical meristem of a plant, that is, the “growth tip”. Those auxins flow down into the plant, where they play a role in:
- root elongation
- promoting the formation of more lateral (branching) roots, and root hairs as applicable
- enlarging the thickness and length of roots
- increasing the uptake area and uptake activity of the roots
- increasing the number of root tips
- cambium activity – increasing segment thickness and the creation of more vascular bundles, allowing easier transfer of nutrients and fuels throughout the plant.
- leaf expansion, and the angle at which they are held
- differentiation of vascular tissue – enhances movement of chemicals on-board
- stem cell elongation
It is that expansion of the root system that is of most interest, as it is the newly-growing root tips that produce cytokinins, and as they travel upward through the plant:
- they induce cell division and elongation
- increase of nitrate reductase vitality promoting nitrogen uptake
- slow leaf and flower senescence
- affects the emergence of lateral bud and flower development
- enlarges leaf area
- play a role in the osmotic pressure in roots, thereby promoting greater water uptake and transport throughout the plant.
- induction of cell division and growing tips promotes younger shoots to grow big and strong more quickly
That last item, the stimulation of the shoot growth tips, in turn releases more auxins, and the process recycles. Each phase starts slow, builds to a peak, then begins to fade, like a series of overlapping bell curves. The image below is a simplified representation; in reality the cycling would be better represented by a multitude of closely-overlapping, but diminishing curves over the time period. In most plants, a complete cycle takes about 14-21 days, which explains the recommendation to only “boost” the plants every three weeks or so (I recommend monthly application.)
By the use of kelp biostimulants, we “cut into” that natural cycle, pushing the plant into a “higher gear” if you will, accelerating all of those processes, giving us healthier, faster growing plants.
The degree of stimulation resulting from Kelpak application goes far beyond what would be expected from the hormone content, and can be explained by the synergy of the variety and concentrations of the other, natural phytochemicals present.
Below is a typical analysis of Kelpak showing the wide array of stimulants and nutrients available in the formula:
AMINO ACIDS (mg/L)
GROWTH REGULATORS (pg/L)