Optigrow produces the oldest and most successful compound used in fertilisation and soil remediation in history.

Over 50 years of research show how effective this compound is and it can be found in all the healthiest soil ecosystems on our planet.

It is a compound that physically, chemically and biologically stabilises soil, stimulates further plant growth even when plants are already receiving optimal nutrition.

Includes plant-growth regulators which increase growth and yield.

Consistently improves seed germination, enhances seedling development and growth, and increases plant productivity.

It has been proven to effectively control or regulate, pests, fungus, disease, soil toxicity and chemical imbalance.

It is a compound that exists in all healthy soil and if you as a farmer, are suffering from an unhealthy soil, your soil in all likelihood, is missing it.

So who are we and what is this compound I am talking about.

 Optigrow produces Opti-cast, also commonly known as earth worms castings.

We produce primarily for Mpumalanga’s fruit, nut and veg industries.


So what exactly is worm castings?

Vermicast is a thick black compound produced by earthworms,

a living fertiliser and soil rehabilitator that is highly microbially active.

It  makes available nutrient more plant available, microbial activity makes minerals and micro nutrients otherwise locked away in mineral sand, soluble, making them available to plants.

The microbial activity and physical structure of vermicast stabilizes chemicals and minerals within the substrate keeping nutrient available more consistently and for longer and  helps stabilize moisture levels in soil leading to reduced drain away.


Castings work in a multi faceted approach.

It is a natural process that supports all the elements plants and trees need for sustained healthy growth, encompassing

  • Physical property.
  • Chemical state.
  • Biological activity.

With these three in check, trees and plants have the best environment for healthy growth.

Optigrow works with farmers like you to restore your struggling soil, to reintroduce the missing puzzle piece that modern agriculture is only now realising it has lost, to decrease chemical fertiliser costs, increase yield, increase quality and control disease and pests.

We aim to help rebuild your soil by the reintroduction of organic methods, integrating into and working with your current chemical fertilisation schedules to better the results you aim to achieve.

And all this we endeavor to do within your current budget.


What is soil?

Soil is certainly not simply a sterile growth medium.

It is a complex web of mutualistic and symbiotic interaction, complex relationships between plants and animals both big and microscopic.

It is the backbone of our food system; your greatest asset and greatest resource.

It is comprised of two main components, mineral sand  and  organic matter, but that is not the whole picture.

In order to support plants, soil health is based on three components.

It’s that Physical, Chemical and Biological structure.

The three structures within soil that worm castings work to naturally repair.

The Physical structure of soil is what holds moisture in place so that roots don’t  become either too dry or to wet. Holds chemicals in place so they are available to plants without being washed away.

Chemical structure is having a readily available supply of all the nutrient plants need to grow and thrive, but most importantly in plant available formats that plants can readily absorb.

And finally the biological structure of soil.
Probably the most important component in soil. It is the microbial activity within soil that works on the chemical fertiliser we add, the nutrient and micronutrient, to convert it into the plant available formats plants require.

nitrifying bacteriacfans_asset_249211

Earthworms do not create nutrient they simple refine it from their food source and convert it into a format that is the most efficient form for plants to take up.

During the process  organic matter passes through the worm’s gut, it undergoes physio-chemical and biochemical changes by the combined effect of earthworm and microbial activities.

Worm castings or vermicasts, are coated with   mucopolysaccharides and enriched with nutrients.

The biota introduced to the soil in vermicast or leachate (worm tea) can work away out of sight, releasing the minerals that are already there.

Worm castings can be as much as 1000 times as microbially active as conventional compost, with compost being higher in ammonium, while castings are higher in nitrates, which is the more plant-available form of nitrogen.

With the introduction of castings and its biota, supply rate of nutrients like  P, K, S and Mg, are increased.

Earth worm castings are an excellent media for harbouring N-fixing bacteria, also trapping free nitrogen from the atmosphere.

Nitrogen fixation is a process by which relatively inert  atmospheric molecular nitrogen (N2) is converted into ammonium (NH4+) freeing up the nitrogen atoms to be used in other ways for in the case of castings, to be converted to nitrates.

As farmers all know, this is essential because nitrogen is required to create the basic building blocks of plants, therefore  essential for agriculture.

Earthworms directly cycle this nitrogen by excretion in their casts, urine and mucoprotein and nitrifying and nitrogen fixing microbes are all found established in worm casts.

Several valuable compounds are also produced through the earthworm  and microfloral interaction, which included vitamins such as B12 and plant growth hormones (gibberellins).


Cationic exchange is important in your soil, but what is it.

Trace elements are attracted to worm castings and readily bond to it in the same way that opposite poles of a magnet attract each other.

Everything in nature has an electrical charge. Some charges are positive, cations, and some are negative, anions. Organic vegetative matter is anionic and, because worm castings are highly vegetative matter, it is strongly anionic. Most trace elements are cationic.

Earth worm castings act like a sponge using their charge to hold trace elements in place increasing bio availability of that nutrient for when plants need it.

Plants have a stronger pull than the worm castings and can therefore draw the trace elements away from the castings and into their roots.

 Pythium  Sphaerotheca fulginae - Copy

There are extensive studies regarding disease attacks on crops.

Results consistently show with small applications of castings, the incidence of disease is significantly suppressed.

(by Pythium on cucumbers, Rhizoctonia on radishes, and by Verticillium on strawberries and Phomopsis and Sphaerotheca fulginae on grapes in the field.)

Earthworm movements act to disperse not only microorganisms important in food production but also root symbiots that form mutualistic  associations between  fungus and the roots of a vascular plant.

In addition microbial antagonists of plant pathogens and pest microorganisms are also dispersed, microbes that eat or destroy other plant pathogens or pest microorganisms.

Phytophthora nicotiniae sclerotinia sclerotium fusarium oxysporum

Researchers have found that instances of fungus can be controlled with the use of worm castings.

Studies showed a generous application of earth worm castings were required but clear improvement showed in less than 30 days.

Worm castings have been found very effective in combating Phytophthora in macadamias.

(Phytophthora nicotiniae, fusarium oxysporum, sclerotinia sclerotium, and sclerotum cepivorum,)

Chitinase-1CNSBathycoelia natalicola

So what about those pesky insects and how do worm castings effect them.

Chitin is a compound that makes up the main component of the exoskeleton of insects.
Chitinase is the naturally occurring enzyme that breaks chitin down into chitosan.

Worm castings contain enzymes known as various forms of chitinase of which insects have a strong aversion.

Worm castings activate multiplication of the chitinase-producing bacteria found naturally in plants.

The natural level of chitinase found in most plants is not sufficient to repel insects.

The level of chitinase is multiplied to a repulsion level with the use of worm castings.

When the chitinase concentration is low, insects are not repelled.

The increase in the chitinase level on small plants to a level sufficient to repel small insects occurs in a few weeks. The increase in the level of chitinase in large plants sufficient to repel the insects takes longer.

To better demonstrate.
The level of the chitinase enzyme for effective repellence is in the range of 1 million cfu/gdw (Colony Forming Units/ gram dry weight).

Worm castings level of the chitinase enzyme production shows concentrations of chitinase in the range of 54 million CFU/gdw.

This is concentration is over 50 times the estimated level for repellence and the likely reason why ants refuse to cross a layer of worm castings.

Castings can effectively repel insects that feed on the internal liquid of various plants.

These include a large array of insect pests including white fly, aphids, spider mites, fruit flies, and other nectar-sucking insects.

Studies with white fly infested hibiscus plants treated with worm castings were free of all white fly residue and cocoons In about two months.

White flies from neighbouring plants, which had not been treated, would fly around the treated leaves but not land on these leaves.

heavy metals

Other issues farmers face with soil degradation is the issues of soil toxicity and chemical imbalance caused by fertiliser and pesticide use in the absence of healthy ongoing soil management.

Earthworms have been found to be a viable method of removing toxins from soils and enhance the remediation of agricultural lands polluted by chemicals the likes of say.. DDT.


Earthworms can live in highly contaminated soils.

They are generally  tolerant to many chemical contaminants including heavy metals and organic pollutants in soil and can bio-accumulate them in their tissues.

Earthworms species like Eisenia fetida have been found to through the use of a special detoxifying layer in their gut and specific metal binding proteins,   remove and isolate toxic heavy metals such as (Cu, Cd, Pb, Hg, Zn, etc.) and also lipophilic organic micropollutants from soil.

Chemical contaminants are absorbed through their moist body walls  and  mouth and are either bio-transformed or biodegrade , rendering them harmless in their bodies.

This makes earthworms perfect for soil remediation in both agricultural and industrial settings.

sa agricultureDue to high chemical costs in india, there has been a large move to farming with earth worm castings.

In turn a lot of data has emerged and studies in India have consistently shown water reduced for irrigation as worm castings over successive years improved the ‘moisture holding capacity’ of soil.

PEST attack reduced – by at least 75% in crops applied with castings.

Cauliflowers 95% ‘disease free

Bananas –  Late Blight (fungal disease) reduced by over 95%.

Reduced termite attack

Weeds Reduced

Seed germination occurred at a faster rate with rapid seedlings growth and development.

An increase in yield

Greater numbers of fruits per plant (in vegetable crops)

Greater numbers of seeds per ear (in cereal crops), larger, heavier and better quality .

Flower production (commercial floriculture) was increased by 30-50%

Flower blooms were more colorful and bigger in size.

Better quality and taste of Fruits and vegetables

Longer shelf life over twice that of the control.


In the United States.

A 13 year Iowa State University study farming strawberries found:

Healthier berries and soils

Improved pollination success

No need for pesticides to maintain crop yields.


In South Africa

A Free State Commercial Apple Farmer found using vermicast and tea in its apple production system

Improved fruit quality

Reduced input costs

Improved the soil and tree health in orchards.

Earthworm activity evolved mineral soil into rich healthy soil with the earthworms managing the environment.

One-third reduction in irrigation water.

Increase in root growth

This increased nutrient uptake has resulted in healthier, stronger apple trees.

Incorporating earthworms has increased yields 15 to 25 t/ha depending on variety.


A changing in international export regulations, specifically for chemical residue levels and a shrinking list of usable chemicals drove their search for alternative techniques.

So where to start?

The best way to get started is to arrange a consultation so we can discuss your needs, your infrastructure and appropriate method of application.

Implementing Opti-cast and using it in conjunction with your current chemical regime, unlike using chemical fertilisers alone is a specific process with a specific goal in mind.

Time scale wise we advise planning for 1 to 3 years of worm casting application, twice annually,  depending on your existing soil environment and working towards a regeneration of your soil.

Our  aim if for an ongoing working relationship with our farmers to get their soil to optimum condition and keep it there, we encourage our farmers to include a high quality compost in their feeding schedule, if they would like to take advantage of the added benefit of baby worms and cocoons in Optigrow Opti-cast.

Results are commonly seen very quickly and ongoingly.

In time you will see the levels of chemical fertilisers required reduce until a point where worm casting application can be scaled right back and chemical application can remain greatly reduced.

Thereafter a schedule of composting can be used to maintain your soil with worm castings being applied in problem areas.

This equates to a huge potential cost saving to farmers in the long run.

As with all things, organic soil restoration is a process, but with fantastic benefits.



For best results, we advise and application of 2l of Opti-cast to established trees, twice a year.

1L for established small trees and shrubs, twice a year.

100 ml – 250 ml for seedlings on planting, snugly around the root base.


We do however advise 2L when planting new trees.
The reason for this being that it is the most opportune time to get earth worm castings at and in contact with the root base of the tree, having the ability to have its maximum benefit.

Young trees are at their most vulnerable and castings at the root base will work towards supporting it and giving it a strong healthy start.

Worm castings is a powder, but can be applied in two ways.

Applied manually in its powdered form or used to produce Opti-feed, a vermileachate or worm tea that can be sprayed or incorporated into a fertigation system.

Manual application is simple enough, applying in the case of a sprayer or dripper between the spray/drip head and the base of the tree.

Vermileachate can easily be percolated in tanks, aerated and delivered through a fertigation system, manual sprayer or crop sprayer.

Foliar feeding is highly beneficial both for nutrient and pest resistance benefits.


Opti-cast is supplied by the cubic meter in 40dm bags (40l).

Per cube this equates to 500 trees, 1000 shrubs or 4 000 to 10 000 seedlings.

Using this you can calculate your cost per block or hectare.

As this is a compound that starts the regenerative process immediately, application can start at a farmers earliest convenience, where after it can be incorporated into your existing schedule.

We look forward to working with you towards a healthier and more consistent soil environment.

Reduced stress in your plants with stronger structural growth and root systems.

And of course a longer yield period with larger, healthier, higher grade crops.


Call us today to make an apointment.