Advanced Grow Guide


Hello and welcome from the team at EHG.

We have put together this guide to provide growers with a deeper insight into how our nutrients work and also to answer some of the many questions we have been asked in recent years and experiences we have shared with people growing cannabis legally, both privately at home and in licensed  facilities. It is not intended as a complete guide to cannabis growing, but we have noticed that generally many of the same questions are asked and many of the same mistakes are made. We thought it would be useful to put out something more comprehensive than we have previously, and make it generally available to our many loyal followers.

We will deal with the nutrient program generally and touch on problem areas along the way. Although there are some good sources on the internet there is also a lot of misinformation and for a new grower it can often be very difficult to tell fiction from fact regarding proper feeding and care of cannabis.  It is generally a good idea to be very wary of posts on cannabis forums.

In this guide we will look at proper feeding of cannabis and cover these topics which growers may find useful:

  • What is EHG?
  • The Basic EHG Nutrient program
  • The expert grow schedule
  • Young plants and vegetative growth
  • Seeds vs Cuttings
  • Taking cannabis into flower and finishing off – looking at problem areas along the way and different grow techniques, including auto-flowering plants.
  • Organics and Hydroponics?
  • pH and feeding frequency
  • Growing in soil and coco coir
  • Flushing and run-off EC
  • Feeding mother plants
  • The “Lucas Formula” (and the Head formula)


EHG is a multi-part liquid nutrient primarily designed for hydroponic growing but which also works extremely well in soil. It is highly effective in every kind of hydroponic system whether flood and drain, NFT, drip-fed, Dutch-buckets, auto-pots, deep-water culture, bubble-ponics, aeroponics or any of the many excellent commercially available or DIY hydroponic systems around. The base nutrients are formulated from pure mineral salts without any additives or synthetic hormones and our bio-stimulant range consists of organic kelp, fulvic acid and humates, with added micro-nutrients and calmag in the foliar spray. This guide will demonstrate how to successfully combine the science of hydroponics with the art of organics for top harvests of world-class bud.



The basic nutrient table for cannabis (Also on the label of the Micro (or Coco Micro) bottle and on our website) sets out the simple parameters of the base-nutrient program, combining the various components according to the stage of your plant’s growth. The table is premised on a controlled grow with a switch from 18 hours of light and 6 of darkness to 12 hours of light/darkness when the plants have reached a sufficient size for the grower’s objective and it is time to induce flowering. (The basic idea of indoor cannabis growing.)

The ideal plant size at the change to flower will vary according to various parameters, whether growing one or two plants, or a number of plants in a “sea of green” (SOG). Outdoor growing is slightly different as we will explain below.

As one gains confidence in the use of our products, increasing the nutrient strength is possible, however we advise that this is done gradually, under the correct conditions and within the correct parameters of the plant strain. When increasing the nutrient strength, it is important to maintain the feeding ratios recommended in the basic guide table. We discuss this in more detail below.

When preparing your feeding solution, add each component separately into the same well of water and stir well. Before going ahead with feeding, make sure the pH is correct and you are happy with any other levels you may be monitoring.


There are 3 major elements required for plant growth. (N-Nitrogen, P-Phosphate, and K-Potassium), the primary elements. Plants also require Calcium (Ca) Magnesium (Mg) and Sulphur (S) in smaller amounts, the secondary elements. In soil, micro-nutrients (iron, boron, zinc, copper, manganese and molybdenum) are normally available but in any hydroponic system they must be supplied to the plants.

A properly and scientifically formulated hydroponic nutrient is absolutely essential for optimum performance in any hydroponic system.

The EHG base nutrients are MICRO or COCO MICRO, GROW, BLOOM and RIPENER.

MICRO is formulated with N, Ca, some K and the full range of micronutrients and is used throughout the feeding cycle.

COCO MICRO is similar but is designed for use with coco coir. It has added Ca and Mg and no K, to counteract the tendency of coco coir to absorb Ca and Mg and release K. If growing in coco coir simply replace MICRO with COCO MICRO in the formulations.

GROW and BLOOM have N, P, K and Mg in different combinations to be utilised together with MICRO at different stages of your plants growth to provide the optimum nutrient levels. Grow has a higher emphasis on N and K, while BLOOM increases P and Mg while maintaining high levels of K and reducing N. RIPENER is a finishing product with no N, high P and K as well as S and Mg.


Expert growers are those who take the time and trouble to gain insight into how their plants function. They observe their plants closely and look after them as well as they possibly can by controlling the environment well and feeding optimally. Excuses not to feed or do essential maintenance when they should, do not exist for expert growers, who consistently achieve good results with half the number of products resorted to by novices desperately looking for answers and who are often sadly led into  an expensive and largely unnecessary feeding regime.

Although expert growers have a schedule to follow much like our basic feeding program, they tune in to what their plants need and make changes and adjustments based on experience and observation of their plants’ response to the feeding program and the environment. 

This guide is intended to help private growers on that journey. If you have never grown plants before, there is a lot to take in, particularly for indoor growing where properly controlling the growing environment is the key to success. It is also intended for licensed commercial growers who usually have a good idea of how to grow,  but who will gain a better understanding of how our nutrients combine and function to inform the decisions they will make in their operation.

YOUNG PLANTS (and vegetative growth)

The nutrient table shows a formulation of equal parts MICRO, GROW and BLOOM in the early stages of the plants’ life. This creates a balanced feed with good levels of N and K to promote vegetative growth but also with significant P to aid root development. The table shows only 2,5 mls of each component per 10 litres of nutrient solution in the first two weeks.

This is an extremely gentle feed which gives an EC reading of approximately 0.3 (150ppm) above the existing EC of your water. (EC, or Electrical Conductivity, measures the amount of electrically conductive ions in solution giving a good indication of nutrient strength. It is usually measured in milli-siemens/cm.)

This can be considered a minimum level and you may wish to increase this as your plants develop and grow.


Giving plants that are not growing strongly increased nutrients will not improve growth and will be counter-productive. We’ll look at this further below.


Experience has shown that the early vegetative stage (particularly when using cuttings) is the one which gives new growers by far the most problems, so we will concentrate on some aspects which generally seem to cause issues.

Unhappy growers whose young plants are not doing well will often consult charts on the internet with photographs of cannabis with various problems and may conclude that they have one or another nutrient deficiency.

They may think the problem is that the nutrients aren’t strong enough and begin to heavily overfeed, adding every supplement they can lay their hands on, which only compounds the problem and can lead to the plants dying.

More often than not the problem is rather one or a combination of basic mistakes that need correcting.

Sometimes a problem may appear as a nutrient deficiency, however, when using our nutrients, your plants will not suffer from a nutrient deficiency even at low feeding levels.

With a properly formulated hydroponic nutrient like EHG, if your plants are struggling, it is 99.99% probable that this is because of some form of environmental stress and not a direct nutrient issue.

Soggy, water-logged roots, for example, don’t get enough oxygen and struggle to take up iron. This then appears as an iron deficiency with chlorosis on new leaves.

Damaged roots (from root-rot, for example, in hydro, or root-aphid larvae, in soil) struggle to take up nutrients at all and this will first manifest as a nitrogen deficiency with a yellowing of the lower leaves as the problem worsens.

Browning and spotting of the leaves can be a calcium deficiency but is far more often caused by mould, fungus or insect pests. 

A too low PH will appear as a potassium deficiency with drying of the leaf tips. (The solution is not to add more potassium but to correct your PH.)

The plant may have Leaf-yellowing and a conclusion of N deficiency is reached, however, generally when plants are placed under stress their leaves will also yellow.   It is far more often not a nitrogen deficiency.)

If your plants are not doing well, flush with pH balanced water and then maintain a low-level feed  until the plants improve and try to find the cause of the problem.

Temperature, airflow, humidity levels and water quality could all be culprits and this applies throughout the grow.

Fresh air (supplying carbon dioxide during the day and oxygen at night) is essential and indoor plants will not grow well without a steady supply. Proper air flow and circulation are extremely important.

Unfortunately, for various reasons including mismanagement and heavy e-coli counts, excessive amounts of chlorine are sometimes added to municipal water. This will hurt and may even kill your plants and will drastically reduce your harvest. The use of rainwater (install collection tanks) or clean water from natural sources is advised. Water quality differs between municipalities and treatment plants. If you have no viable alternative to municipal water and there are any doubts about your water quality then the installation of at least an in-line activated charcoal filter at your water supply is strongly recommended. It may also assist to allow the water to stand for several days before use but a decent filtration unit is the way to go.

One of the very reasons to use a properly formulated product like EHG is that if any such symptoms occur you can look immediately for the real problem and not waste time worrying about your nutrients. 

Growing from seed vs cuttings requires different growing techniques and a failure to appreciate the difference between the two could be the cause of various issues.

Seed can be sown in sun or artificial light. A germinating seed adapts to its environment and maintains parity between its structural growth above and its root development below, depending on the conditions it finds itself in.

Cuttings taken from an adult mother-plant are an entirely different proposition. They are kept alive in a rooting medium (essentially a mini-hydroponic system) until they develop roots and grow. Without proper roots they are unable to take up water and must be kept in a humid environment or they will wither and die. For the first few days humidity must be kept as high as 85% and then lowered as roots develop. (Keeping humidity too high for too long without air circulation will encourage fungal problems.)

Most growers are able to successfully root cannabis clones under a humidity dome of some sort or another but it is when the rooted cuttings are planted out that problems arise. Many growers assume, incorrectly, that because a cutting has popped a cluster of nice-looking white roots out of its root-cube, under a dome, it can be treated like any other plant. This is not the case.

The cutting behaves like an adult with the developed root system of its mother plant. Under conditions of low humidity and bright light it transpires water through its leaf stomata, expecting to draw up replacement water through its roots. If the roots aren’t strong enough the plant stresses, turns yellow and will either die or limp along, never reaching full potential.

Taking a rooted cutting from a humidity of 65% – 70% or higher, under a relatively soft light, and putting it into less than 50% humidity directly under powerful lighting, is almost certain to cause problems.

Humidity must be kept up and then gradually dropped as the roots begin to establish themselves in the new grow medium. Likewise, lighting intensity should be increased slowly and as the plants respond with healthy, new green leaves. Temperatures can be from 24 – 28 degrees C, with the optimum around 26/27, slightly higher than for fully established plants in vegetative growth. Following this simple guideline has solved many of the queries we have received from growers having problems with plants taken from cuttings.

It is often challenging to keep humidity high when the through-flow of air from outside is dry. This is particularly so in winter in KZN and the EC and summer in the WC when the air can be very dry, and most of the year in the highveld.

Airflow is extremely important in an indoor grow. Its purpose is primarily to provide fresh CO2 to growing plants. It is far better to compromise your airflow to keep humidity high than to dry out your plants.

Young, barely-rooted cuttings are not, in any event, growing strongly and do not need huge amounts of CO2. A warm, humid environment is far more important at this stage. Air replacement 2-3 times per 24 hours is more than enough.

Again, as the plants develop and light intensity is increased, the airflow is increased. Patience is the key.

Done correctly, this process is short and the plants respond quickly. Done incorrectly, your stressed plants may take days or weeks to recover.

If you need to pull air out to prevent heat build-up in hot weather, keep it to a minimum or use lights which don’t give off too much heat until the plants are stronger. Cool white LEDs or fluorescent lights are very effective for this.


It will be noted from the nutrient table that it shows only 3 weeks in 18 hours of light for vegetative growth, before switching to 12 hours of light in flower.

In the 3rd week of veg (18/6) the feeding rate has risen to 7 mls of each GROW, MICRO and BLOOM per 10 litres of water. This gives an EC of around 0.8 but as pointed out above, this can be ramped up if your plants are healthy and responding and double this amount, at an EC of 1.6 is an acceptable figure for cannabis at the end of veg, particularly for larger plants.

In the 6 weeks after the change to 12 hrs in flower, nutrient is fed at a total of 30 mls per 10 litres of water (either 20 mls GROW and 10 mls MICRO in the first 2 weeks, or 20 mls BLOOM and 10 mls MICRO from weeks 3 to 6). This gives an EC reading of around 1.2 (600ppm) above the EC of your water. This is conservative for flowering cannabis and a 50% increase on these amounts (to an EC of 1.8) would be a more average figure. (Many growers will push to an EC of 2.0, or higher, if growing in added CO2.)

To increase EC, you simply keep the ratios between the different components the same and increase the amounts proportionately to get the EC required. (For example, if a total of 30 mls of nutrient gives an EC of 1.2 in 10 litres of water, then 45 mls in total will give around 1.8. Feeding a total of 60 mls (double the base-line strength) will give an EC of 2.4).

Alternatively, you can use an EC meter, but good ones can be expensive and a bit of basic arithmetic will do the job if necessary. (Obviously, no commercial grower should be without a quality EC meter.)

The following are important things to consider in order to get the most out of your plants and nutrients: Growing methods vary from plant to plant and therefore knowing when to switch from veg to flower is important.

  • The 3-week period of vegetative growth on the nutrient table is representative as this period can vary. 3 weeks would be a fairly short veg period and intended to produce small plants for packing into a SOG. (At the opposite end of the spectrum is an outdoor plant, started in spring and intended to veg the entire summer until it starts its flower cycle naturally in late summer/autumn.)
  • The 2:1 GROW to MICRO ratio in the first two weeks of flower is designed to accommodate the “stretch” which all cannabis plants experience if they are induced to flower by switching from an 18-24 hour day-length to a 12/12 light cycle. After the balanced feed given to the smaller plants in the first 3 weeks as explained above, the root systems should be well established to support the stretch and the phosphate is not required as much. This GROW/MICRO ratio is designed to provide ample N and K to drive the formation of branches and leaves to hold the buds which are on the way. Sativa dominants usually stretch more than Indica dominants but even Indicas will normally more or less double in height in the first 2 to 3 weeks of flower.
  • After 2 weeks of flower, small buds will be forming everywhere and from the 3rd week the spike of the main cola will start pushing up to its final height with most strains. It is time to switch to the 2:1 BLOOM to MICRO feed to push the bud production and take the emphasis off leaf production by dropping N and increasing P. (K also goes up slightly in the BLOOM/MICRO feed.)
  • Plants with a vegetative growth period longer than 4-5 weeks can be switched from the equal parts GROW, MICRO and BLOOM ratio to the 2:1 GROW to MICRO ratio earlier than the first week of flower, if the grower is satisfied with the root development and wants to put more emphasis on bigger, bushier plants.
  • An outdoor plant, for example, planted in spring, could stay on equal parts until the end of November but switch to 2:1 GROW to MICRO in December and stay on that until the first sign of flower buds appearing. At that point change immediately to the 2:1 BLOOM to MICRO ratio. As the outdoor plant’s day length changes continually by small increments and there is no sudden stretch caused by a 18/6 to 12/12 switch, the parameters are a little different.
  • When growing indoors in a screen of green (SCROG), veg time is determined simply by how long it takes for your plant (or plants) to grow into the screen sufficiently for your purposes. This will depend on the size of your screen and the number of plants involved. Similar parameters apply. If it is taking more than 4 weeks to get the screen to where you want it before inducing flower, switch to the GROW/MICRO formulation earlier to boost structural growth into the screen.
  • Some growers will also vary the 2 week period after switching to flower that the GROW/MICRO ratio is applied. Very long-flowering Sativas can stay on this ratio for longer as the onset of flowering is slower and the stretch more pronounced.
  • Conversely, fast-flowering, shorter Indica strains may need less than 2 weeks before bud development kicks in strongly and switching to the BLOOM:MICRO formulation is a good idea.
  • Autoflowering plants don’t need a change in day length to flower and will usually show signs of flower around 4-5 weeks from when the seed germinates. There is little or no stretch and the plants have a very fast cycle. Feed for the first 3 weeks with equal parts GROW, MICRO and BLOOM. (Start at the base feed and push up nutrient strength as the plant responds.) Feed for one week at 2:1 GROW to MICRO. (Don’t go much higher than around 30 mls GROW to 15 mls MICRO per 10 litres and an EC of around 1.8-2.0. The plants stay relatively small and won’t use a huge amount of nutrients.) From the beginning of week 5 onward you should see buds starting. Feed at 2:1 BLOOM to MICRO until 10 days before harvest and then use plain water only..
  • If you are growing under indoor lights in a SOG, it is a good idea to prune the lower branches of the plant quite heavily at around the end of the first week of flower. Artificial light creates a “band” of effective light, the  depth of  which depends on the intensity of the  light source. Too close to the light and the plants will stress and show signs of leaf burn, too far and they are not getting enough light to grow properly. Prune off small side branches which are unlikely to reach the effective light band and create an even canopy. Pruning off smaller branches which will sit under this canopy without much light will increase both final yield and bud-size. It also increases air circulation under the canopy.



If you have healthy plants with thick stems and a nice main cola starting to develop after the first couple of weeks of flower then most of the hard work is done and a decent harvest can be expected, barring any unforeseen eventualities. You may have topped or trained the plants in veg to create a bushier structure and have more than one top cola but the development and bud structure will still give you a good idea of what can be expected. This is a very gratifying time for the cannabis grower when the hard work put in earlier starts to reap rewards, but care is still needed.

With indoor and greenhouse grows, good strong airflow is extremely important at this stage and the maximum possible amount of air should be drawn through the grow environment after the 12/12 switch to flower (or sooner). Not only does this provide the needed CO2 but, once buds start to pick up weight, low humidity is key to preventing moulds which can destroy a harvest. The plants transpire heavily and moist air must be constantly pulled out of the grow. Humidity levels of less than 50% are advised if possible. The only exception to this may be where the outside air is exceptionally cold and there might have to be a compromise between airflow and temperature. Cannabis flowers naturally when winter approaches and temperatures as low as 20-24 degrees C in late flower are perfectly acceptable. When the lights are off, even 16-18 degrees C is fine. Combined with low humidity these temperatures ensure good bud quality. Don’t compromise on airflow unless absolutely necessary. If you are flowering indoor during the wet season (winter in the WC and summer most other places) long periods of wet weather make it difficult to lower your humidity as you are just pulling in equally moist air from outside. Concentrate on fast-flowering and mould-resistant strains at this time.


Keep feeding 2:1 BLOOM to MICRO at an EC of around 1.8-2.2 and enjoy the sight of your plants really starting to perform. (At higher levels keep an eye out for leaf tip burn or curling which indicate your nutrient may be too strong.) Bear in mind that the chances of salt build-up in your medium increase at higher ECs. Flush at least every 2 weeks if feeding at an EC of 1.8, or higher. During cold weather try and keep your nutrient solution above a minimum of 18 degrees. For smaller grows use an immersion heater or a thermostatically controlled aquarium heater in the reservoir.

The Nutrient Table shows an 8 week flower period with 6 weeks of feeding and a 2 week period without nutrients at the end. This is only a guide as many strains will take longer than 8 weeks to finish (and some less). Simply extend the period accordingly and continue to feed at your chosen nutrient strength until 2 weeks before the harvest date when flushing with pH balanced water only is needed.


RIPENER is used as a finishing product and as a flowering P and K booster at a rate of 5-7 mls per 10 litres of water from the end of week 3 of flower.  Because it has no nitrogen it can also be used as a replacement for BLOOM in increasing quantities toward the end of the feeding period. This has the effect of reducing the nitrogen in the nutrient solution and increases the “fade”, the slow yellowing of the leaves from the bottom up as the plants near the end of their life. Many growers prefer not to lower the nitrogen and stay with the standard formulation as they find that the 2-week flush without nutrients at the end is more than sufficient to ensure a good fade of the lower leaves by harvest. (This is also an indication that any excess nitrogen has been metabolised by the plant.) Others swear by significantly reducing nitrogen and believe that bud quality is higher in plants which fade very noticeably before the end of their life.

For example, if you are feeding at 30 mls of BLOOM to 15 mls of MICRO per 10 litres from week 3 of flower –  you could switch to 15 mls of RIPENER and 15 mls of BLOOM to 15 mls of MICRO, 2 weeks from your final feed, and 30 mls RIPENER, no BLOOM and 15 mls MICRO in the last week. This will reduce N toward the end of flower. The 5-7 mls RIPENER as a PK boost can be added in addition to this, depending on your desired final nutrient strength. (See also the comments about the Lucas Formula below.)

Some growers will drop all nutrients in the first week of the final flush (as normal) but continue with as high as 30 mls/10 litres of RIPENER into the first week of the flush and give water only for the last week before harvest. Much regarding the use of RIPENER will depend on the strain of plant and your general growing practices. If you are finding that your plants are not ripening as well as they should then try increasing the ratio of RIPENER to BLOOM in the final few weeks in your next grow with that strain. If you are starting a new strain stick to a more basic formulation and see how it goes.


“Can I add organics to my hydro nutrient reservoir?” Is a question we are very frequently asked. The general answer is – NO, ABSOLUTELY NOT!

“Hydroponics” is – by definition – the practice of growing without soil and providing plants’ roots with everything they need in a nutrient solution. Most organics need to be broken down in soil by organisms before they provide any significant benefit to plants. This generally does not happen in a soil-less medium which is the whole reason for providing a precisely formulated hydro-nutrient.

The other main objection to organics in the hydroponic reservoir is that most rapidly begin to break down and this process both takes oxygen from the solution and encourages root-rot and the growth of potentially toxic organisms. Not only can this be seriously detrimental to your plants’ health but the resultant sludge will clog your medium and your feed delivery system, particularly if you are using a drip-feed as the majority of commercial systems do.

One possible exception to this is hand-fed coco coir which can handle a certain amount of organic load but even this is very seldom worth the effort as the factors needed to utilise the nutrients properly are not present.  Organic nutrients must be mixed and used immediately and not allowed to sit for any length of time or problems start. (Molasses or fish emulsion, for example, will turn into a smelly soup within 24 hours of being put into solution.) The great benefits of hydro are lost if you complicate the equation by introducing organic additives which your system was never designed to handle and which are of little benefit to your plants. If you manage to clog your drippers or other feeding systems with organic sludge, it’s probably easier to throw them away and start again.

A very important exception to this is FULVIC ACID. EHG pioneered the use of humates (naturally occurring substances which include fulvic acid) in hydroponics in South Africa with great success but we have discovered through our research that the benefit for hydro comes from the fulvic acid portion of the humates.

The larger organic molecules in humate cling to soil particles and water molecules and greatly improve the quality and water retention of soil. In hydro, the much smaller fulvic acid molecules act as organic chelators and assist the uptake of nutrients through the plants’ roots as well as improving root health.

The fulvic acid does not break down rapidly and can be mixed with the other nutrients and kept in the reservoir without issues, even with recirculating hydro systems which reuse the nutrient solution constantly. This is hugely significant for hydroponics.

Used as directed in hydroponic systems, EHG’s Fulvi-Force (registration pending) will result in increased nutrient uptake without any added stress to the plants and generally boosts plant-health and vitality, significantly improving yields.


“So how do we get the benefits of organics with hydro?” …we are invariably asked.  “What about kelp? Vermi-compost? Alfalfa (lucerne)? Guano? Aren’t these beneficial fertilisers?”  Well… yes, they can be, just not in your reservoir. Roots are not the only means by which plants absorb nutrients and cannabis is one of those plants that responds exceptionally well to foliar feeds. Most organic feeds can be formulated as a foliar spray and the benefits of kelp sprays are legendary. Aerated-compost and alfalfa/lucerne teas are beneficial as a foliar spray and there is no need to put them in your reservoir. An internet search for any of these ingredients as a foliar feed will produce comprehensive instructions, if you feel inclined to try them.

Numerous studies have demonstrated the benefit of applying both kelp and chelated micro-nutrients as a foliar spray for plants. Ecklonia maxima, or “sea-bamboo”, is harvested from the nutrient rich waters of the Western Cape and, in addition to a broad range of enzymes and nutrients, it contains the natural growth hormones auxin and cytokinin.

EHG’s Thrive foliar-spray (Registration pending), combines the benefits of kelp with a full range of essential micro-nutrients, calmag and  fulvic acid chelation to ensure nutrient uptake. It is an excellent general tonic for plants and is particularly important when plants are stressed and may be struggling to take up nutrients through their roots.  Seedlings, cuttings and any transplanted plants thrive on it.



Hydroponic cannabis should be fed at a PH of around 6. This is in the middle of the acceptable range and being 0.1 – 0.3 off occasionally is not a big issue. EHG is formulated to be slightly acidic and using it as directed generally drops the PH to around the right level but obviously this depends on how much is being used and the starting PH of your water.

Our simple to use and inexpensive PH test kit will accurately put you in the right range. Use EHG PH UP and PH DOWN to adjust to the desired level.

Bear in mind that with recirculating hydro systems, particularly when the plants are growing strongly and taking up a large amount of nutrients, PH in the reservoir can change rapidly and must be checked frequently unless you are very familiar with your system and can predict the PH variance.

Something which seems to trouble a lot of growers is frequency of feeding.  In some kinds of growing like bubbleponics or an aero-flo type system, the nutrient solution is constantly in contact with the plants’ roots and timing is not an issue. In recirculating systems such as flood-and-drain or dutch-buckets, the same nutrient solution is usually recirculated for a week or more and nutrients are obviously given at every feed.  The frequency of the flood in a F&D, for example, is dependent on various things but the most important is how much nutrient your medium holds and how quickly it dries. Specific instructions for each of the various types of hydroponic systems is beyond the scope of this guide but a big advantage of these systems is that flushing the medium can be done very effectively at a scheduled nutrient change by filling the reservoir with plain ph balanced water and running as normal for 24 hours. Non-recirculating systems (the majority of which use coco coir) and soil growing bear special mention.


Cannabis can obviously be grown in good, healthy soil. Our previous short guide recommended soil growing for new growers because it is very forgiving (although growing hydroponically in coco coir is also very simple and is becoming a popular choice for many first-time growers).

Soil should not be fed as regularly as a hydroponic system and generally benefits from being allowed to dry out from time to time. The water holding ability of your soil can be manipulated by adding coco coir to increase water retention and perlite to increase drainage.

A healthy combination of the two is the best option. Soil that has a fairly high percentage of perlite (10-20%) can be watered more regularly and around 15-25% coco coir will keep the soil well hydrated and help prevent dry spots.

Many growers using non-recirculating (run-to-waste) systems alternate a very high EC feed with one or even two plain waterings. There really isn’t much point to this. It is better to feed at a lower EC and keep it consistent. Flush more often at high ECs. In soil, flush well with plain water and make sure the pot is fully saturated without dry spots. (Coco coir helps a lot with this.)

Then hold off any feeding after the flush until the soil appears dry on the surface but is still damp below. Commence feeding as normal. Small plants in big pots may only need feeding every 3 or 4 days but big plants in low humidity will suck up large amounts and feeding every two days in soil is a good rule of thumb for larger plants.

EHG is fully compatible with organic growing and the pure mineral salts from which it is formulated do not adversely affect soil micro-organisms in any way. Various organic feeds may be beneficial in a soil grow and the strength of EHG used can be reduced according to the amount of organic fertiliser applied. (If you are drip-feeding in soil, the same precautions about liquid organics in your feeding system mentioned earlier apply. Rather feed the organic fertilisers separately by hand or immediately flush your dripper system after an organic feed.) BLACK GOLD, our humate product (registration pending), is an excellent additive for growing with EHG nutrients in soil. Accurate nutrient ratios are difficult with organics and keeping a good base-line of EHG will ensure bumper harvests and quality bud.


In the last 20 years, coco coir has become increasingly popular as a hydroponic medium and growing in coco is sometimes referred to as coco-ponics. It is a good choice for first-time indoor growers as it is inexpensive and easy to use.

It has several advantages over soil, not least of which are that it remains evenly hydrated and does not attract soil-based pests such as root aphids and fungus gnats, which is a real blessing for the indoor grower. It is environmentally friendly and is a natural by-product of the coconut industry.

There are many excellent hydro systems for both private and commercial growing but coco is increasing in popularity in commercial indoor and greenhouse growing as well, for many of the same reasons.  Drip-fed coco is a simple and effective hydroponic growing technique for commercial growing and can be set up with far less infrastructure and cost than most other systems. It is not surprising that we are receiving more and more enquiries about its use.

Coco is not completely inert and tends to absorb calcium and magnesium and release potassium. If using coco, it is imperative that a scientifically formulated, coco-specific nutrient is used to counteract this and to ensure proper growth. Several years ago we formulated and registered our COCO MICRO which remains the only coco-specific nutrient produced in SA. It is also unique world-wide in that the necessary changes are done in the MICRO only and the other components of the system stay the same. You simply replace normal MICRO with COCO MICRO in the formulations.

When coco coir was first introduced as a hydroponic medium many years ago, it contained a high percentage of coconut fibre in relation to the more porous coco pith. The combination of pith and fibre gave an excellent medium which both drained well and held significant amounts of nutrient. In recent years there has been increasing demand for coco fibre for other uses and perlite is now being added to the pith to make it lighter and better draining. If you can find coco which includes a lot of fibre, use it. Coco must be well washed and preferably buffered with calcium and magnesium before use. Many commercial brands which claim to be properly washed still have residual salt in them and unless you are very confident of the quality, you should wash it again.

Some very good growers like to include cal/mag in their flush when growing in coco. EHG’s CalMag Plus is perfect for this. It contains good levels of Calcium and Magnesium and chelated Iron in the right proportions.

There are various feeding options with coco as its draining properties can be manipulated by adding more or less perlite or fibre.  Fast-draining, porous, hydroponic media with plenty of air can be fed more frequently without the risk of becoming waterlogged and consequent problems.

This frequent feeding followed by periods where the wet roots get plenty of air is the basis of the hydroponic method and is the driving factor behind the massive, high-quality yields that can be obtained with hydro. This is particularly so for cannabis which is generally a heavy feeder and which likes its roots well aerated.

Coco pith with 50% perlite or fibre (or a combination of the two) drains extremely well and there is virtually no risk of waterlogging.  We recommend that recirculating systems (commercial or private) should use such a fast-draining medium which can be fed every day and up to 3 times a day with drip-feeders (or other automated systems) for the full hydroponic benefit.

But what about systems that don’t recirculate the nutrients and growers who do not want to feed that frequently? By reducing the amount of perlite or fibre you can increase the amount of nutrient liquid the coco medium holds and feeding can be cut to every second or third day (depending on how quickly the medium dries). Reducing perlite/fibre to as low as 20% will have the desired effect. Pot size also plays a part so there is no set formula. (Some growers use very little or no perlite and feed only every 3-5 days. While many swear by their results, generally a more frequent feed of fresh nutrients will have a better effect.)

“But aren’t I wasting nutrients if I don’t recirculate and I feed frequently?” …is a question often asked, and the answer is no, not if it is done correctly. Run-to-waste coco should be fed slowly to the point of run-off. This ensures that the nutrient solution drawn up by the plants is replaced with fresh solution without significant waste. The coco stays evenly hydrated and the perlite or fibre keeps it sufficiently aerated. While we generally recommend recirculating hydro-systems and a fast-draining medium for the best results, this extremely simple coco-run-to-waste system can be very effective. As always, the risk of salt buildup is greater at higher nutrient strengths. If feeding at an EC of 1.8, flush the coco well with plain water (or water and Calmag Plus) at least every 14 days.


If you have an EC meter then you can monitor salt build-up in your medium by testing the run-off EC. This can be extremely useful and takes some of the guesswork out of the equation. The EC in your medium may be higher or lower than the nutrient you feed.

This will depend on the rate at which the salts are being used by the plant, the amount of water they are drawing up through transpiration, and evaporation in the medium.  If you measure the EC of the run-off after a feed and it is more than 10% higher than what you have put in then this is something you should correct. Feeding more frequently with increased run-off will often bring the level down but, if not, then you should either drop your EC level slightly or flush more frequently.

Conversely if your run-off EC is consistently lower than your input then the plants are using more nutrient than you are providing and your EC can be increased.

There is some debate about the issue of flushing cannabis in coco coir and some growers maintain that it should not be necessary and that with proper management a constant EC in your medium can be maintained through-out the cycle. We disagree.

  • No nutrient is perfect and can predict exactly what specific elements the plant will take up at any given time. (And different strains have different requirements anyway.)
  • Inevitably, elements which are not being utilised will build up in the coco unless you are feeding with a lot of run-off which wastes nutrients and creates a potential disposal problem.
  • It is for this very reason that, with recirculating systems, while it is acceptable to top up the reservoir with nutrients for a while, periodically, a complete nutrient change is needed.
  • There is no harm in a plain water or low EC Calmag flush and, in our experience, plants respond well to it.
  • It also allows for a good opportunity to allow the medium to dry out a bit occasionally without a heavy nutrient load, which your plants will enjoy. (Drying out coco well saturated with nutrients can cause issues.)

(Monitoring levels in recirculating systems is much easier. Just test the EC of the reservoir periodically. If the EC rises – lower your nutrient strength slightly, and if it drops – increase it.)


A mother plant is kept in a constant vegetative state in 18 hours of light and 6 hours of darkness. (Basically, making the plant believe it is in a perpetual midsummer so it never goes into flower.) This provides a constant supply of genetically identical clones for grow-out purposes for indoor growing, often in a SOG where a large number of smaller plants are required. The huge advantage is not only that you don’t have to keep getting seed but also that once you have found a really good phenotype you can use it indefinitely.

The normal rules for vegetative growth apply. Feed small, new moms with equal parts of GROW, MICRO and BLOOM until they are well established and then switch to GROW and MICRO only in a 2:1 ratio for strong vegetative growth. For established moms feed at an EC of 1.2 to 1.8 depending on the strength of the light source supplied to the plant and the amount and frequency of cuttings you want to take.


This deserves a special mention. The Lucas Formula (LF) has been around for many years and was popular for a while in the US. It seems to have had a resurgence in SA, probably as new growers look for answers on the internet, and we are frequently asked if our nutrients can be used for it. The simple answer is – yes, they can – but, as always, we encourage growers to examine why they follow any particular feeding schedule and the effect it may have on their plants.

The LF is based on manipulating the original General Hydroponics (now Terra Aquatica) Flora series schedule which feeds Grow, Micro and Bloom in a 3:2:1, 2:2:2 or 1:2:3 ratio depending on the stage of your plants’ growth (in much the same way that the EHG schedule does, although our ratios and methodology are different). The thinking behind the LF is that there is too much nitrogen in the Flora series formulation and that this is improved by dropping the Grow completely and feeding only Bloom and Micro in a 2:1 ratio (usually in both veg and flower). The suggestion is that there is enough N in the Micro to cater for the plants’ needs and Grow is not actually needed. There are other variations of the LF but that is the basic idea. The LF recommends an EC of 1.8-2.0 in flower which is acceptable. (EHG GROW and BLOOM are different to GH/TA and our formulation drops the GROW completely from the second week of flower anyway.)

If you are thinking of using the LF then consider the following:

  • It is correct that there is enough N in the GH/TA Micro to sustain growth without any noticeable N deficiency if Grow is dropped completely from the GH formulations. (GH/TA Micro has 5% N, Grow only 2% N and there is none in the Bloom.)
  • The problem is that GH/TA Grow is the major contributor of K (potassium) to the equation (6% K in the Grow, 1% in the Micro and 4% in the Bloom) so by dropping the Grow you compromise K.
  • K is a vital component of plant growth throughout the plants’ life-cycle including the flowering stage. Classic hydroponic theory, not only for cannabis, is that N should be lowered when plants are flowering but K should be maintained or increased. (The reduction of K in GH/TA Bloom is an error which is corrected in EHG’s formulations.)

The answer to all of this lies in the discussion about the use of EHG’s RIPENER above and the reduction of N toward the end of the plants’ cycle. EHG RIPENER is very similar to GH Bloom (it has no N) and can be used with EHG Micro in the LF or any of its variations to get the same result. We prefer the approach adopted in the discussion above about the use of RIPENER. The reduction in N, which is the point of the LF, is more relevant at the end of flower and that is why we propose replacing the EHG BLOOM with RIPENER gradually. If you replace all of the BLOOM with RIPENER in the 2:1 ratio with EHG MICRO, you are basically feeding the Lucas Formula at that point. So, in the example given in the discussion about RIPENER above, the 30 mls RIPENER and 15 mls MICRO (with no BLOOM) in the last week of feeding is the Lucas Formula.

If the Lucas Formula really works for you and the way you grow then by all means bring it in earlier in the flower cycle but bear in mind that you will be reducing K as well as N and that may be counter-productive. EHG RIPENER has more K than GH Bloom so it’s a better option for the LF. We would definitely not recommend the LF at any stage before the end of the stretch/second week of flower. From that point Nitrogen is less important.

Some growers take it a step further and drop N by reducing Micro, which has the most N and is therefore more effective. This will also lower Calcium but this is not a huge issue at the very end of flower.

The “Head formula” is a manipulation of the LF intended for growing in coco coir. It does not really make scientific sense in terms of what it is trying to achieve and is irrelevant for our purposes as COCO MICRO is the obvious answer for coco growers. Just substitute COCO MICRO for normal MICRO in whatever formulation you prefer using and you are good to go.


We hope that this fairly brief guide helps you in your growing and that it goes some way to improving the experience. Growing cannabis is great fun and very rewarding for home-growers and an important industry for licensed medical growers. The guide has been prompted by the questions we are routinely asked but also, to an extent, by the misinformation on forums. The internet has revolutionised the transfer of information but the downside of this is that it can be difficult to be sure the information is correct.

There are some very good growers in SA, many of whom have had input into this guide. A lot of growers have developed their own growing techniques and may well have different opinions in relation to various issues above. There are few absolutes and there is always a lot of scope for discussion on any particular subject. As ever, we are always happy to discuss growers’ ideas and experiences.

The Team – EHG