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This tutorial is provided by Hy-Gen's Founder and Chemist, Sandro.


Optimizing the growth of your plants, and finding the correct nutrient level is essential.  

HY-GEN Australia, have developed a selection of nutrient-rich hydroponic solutions that will aid the growth of your plants, with many of them taking into consideration the effects of calcium deficiency in your garden.

Calcium-rich products that eliminate the harmful effects of calcium deficiency play an important role in ensuring your garden thrives. Here, we look at just how important calcium is in the growing process.


How Does Calcium Actively Improve Plant Growth? 

In a nutshell, calcium is responsible for maintaining strong cell structure and vigor. High calcium levels are vital during the late growth stage, as additional calcium will ensure a higher number of flowers are produced and retained by the plant. This is particularly important if you want those flowers to transition into the fruiting stage.

Calcium also plays a critical metabolic role in the removal of carbohydrates, while also neutralizing cell acids.


Some other benefits include:

  • Promotes plant cell elongation
  • Strengthens the structure of the cell wall through the formation of calcium pectate compounds.
  • This will bind cells together and give stability to the cell walls.
  • In doing this, calcium will protect the plant against diseases, as stronger cell walls will make it harder for fungi and bacteria to break through
  • Assists with hormonal and enzymatic processes
  • Improves fruit quality


As you can see, calcium is an essential part of the growing process, and when you’re growing your plants without soil, ensuring your plants have access to all of their essential nutrients is even more important.


What Happens When Plants Become Calcium Deficient?

Calcium deficiencies in plants are usually a result of low calcium availability, or water stress that lowers transpiration rates. 

You can usually tell if a plant has become deficient in calcium if young leaves start to curl or have spots appear on them. Stunted growth, leaf tip burns and aborted flowers or damaged fruit are other signs that your plant isn’t getting enough calcium.

Another variable to consider when observing a calcium deficiency is pH. If the pH of your nutrient solution is not in the desired range, then calcium can become unavailable to the plant, always ensure to check & correct pH.

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Plant nutrition is a broad topic that comes with many challenges. As a new gardener starting out, understanding the elements and how plants absorb/consume them is critical for long term success. Most growers, grow after grow, become much better at understanding their plants and their needs.


Below is a list of elements that cause interactions with others if the ratio is not in synergy:


Excess nitrogen, causes the ratios to shift making Calcium & Potassium unavailable


Excess Phosphorus, can lock out important micro-elements, Zinc, copper & Iron


Excess Potassium, will affect how to plant consumes Calcium & Magnesium


Excess Calcium, reduced availability to Nitrogen, Magnesium, Boron & Phosphorus


Excess Magnesium, locks out Calcium & Potassium leads to complete Micro lockout


Excess Iron, completely restricts Phosphorus and completely locks out Manganese


Excess Manganese, quite rare in excess, but locks out Calcium, Copper, Zinc & Iron



Excess Copper, antagonises Iron, Manganese & Phosphorus


Excess Zinc, antagonises Phosphorus, Copper & Iron


Excess Molybdenum, severe Copper deficiency, further locking out Iron & Zinc


Excess Sodium can create lots of problems limiting Potassium


Excess Boron, Locks out Calcium & Potassium


Excess Sulfur, quite rare, limits Nitrogen, Magnesium, Phosphorus & Calcium


Nutrient antagonism is true for all living systems, if something is in excess there will always be restrictions to other elements. 

Each elemental action is followed by another, if the ratio of this sequence is interrupted then nutritional synergy is affected.




Nutrient ratios are usually correct if you buying pre-made nutrients, the manufacturer usually supplies a feed chart with a set of very specific dosages that increase relative to the growth rate of the plant.

In short, I think if you want to have the most success feeding your plants, less is always more. An interesting experiment to try without too much change is just dropping your EC below 2.0, most people are feeding 2.1-2.4 without including run-off maintenance, usually the run off is high 2 and in some cases 3-4 – at this point you should start to understand if you’re going in at 2.1 and your run off is higher, the plant is consuming very little and a now has concentrated near toxic environment in its rhizosphere (root zone), blocking uptake of all nutrients as a result.

Instead of battling with your reservoir or tank, try running lower EC/PPM nutrient strengths of 1.2 - 1.6  if you were previously using anything near 2.0 or above and you might be surprised with the outcome.

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This is a quick tutorial on what to do (or not to do) if you experience purpling of the stems when transitioning from growth to flower.

A lot of new and experienced growers alike have made a shift to full spectrum LED because of the amazing growth, quality and now finally, amazing yields.

The trade from HPS > LED is most certainly a more cost effective way of producing similar or more in flower weight, for some though an unexpected nutritional response has changed a few things in relation to feeding.

For those with LED lighting systems containing UV light, the purpling of the stems and petioles is completely normal, and is solely an expression of pigmentation, usually displayed by plants that will express purples and reds in late flower during maturity.

If you are using an LED that does not contain any UV LEDs in, then you more than likely have a deficiency.

The deficiencies displayed:

  • Petioles completely change from green to purple > Insufficient amounts of Magnesium (Mg)
  • Main stem has slight pink/purple striping > Insufficient amounts of Potassium (K)

In a majority of cases these deficiencies can be simply corrected by slightly raising the dose of main food/nutrition, particularly increasing your overall A/B base nutrient feed will usually solve this issue. Remember to gradually increase the nutrient strength to avoid and 'burning'.

However in some cases, you may need to amend an additional element in line with the plants needs, one thing to remember though is the synergism and antagonism of nutrients, by adding elements in greater amounts contained in the base food, the concentration can shift making other elements unavailable to the plant.

Never just add something because the bottle says it will fix, ask you local representative as to the potential problems you need to look out for.


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22/2/19 - This is an updated version to a previous tutorial on flushing.

Flushing is a technique used in between feeding weeks to ensure nutrition is available to the plant at all times, it is also used in the maturation (harvest) stage of a plants life. Flushing your plants before you harvest is crucial if you want your crop to be resinous, aromatic and full of flavour.

Flushing your pots or systems free of nutrients allows for both a fresh feeding schedule to resume or allows the plants to consume the remaining nutrients built up within itself. When it comes time to final harvest, if your plants haven’t been effectively 'cleaned', you will have built up nutrient and carbohydrates still within the plant, resulting in a much harsher crop that generally tastes like the nutrients you were plugging them with!

Some cleansing products are dedicated to this phase and specialised solutions actively seek out excess salts and convert them back into useable forms for the plant.


Timing is key with flushing.

Experienced growers understand the benefits of flushing weekly, this will result in a super healthy plant always consuming fresh nutrients.

Plants that go through life not ever being flushed will go through a myriad of problems only confusing the grower.

At A-Grade Hydroponics we recommend gardeners to flush regularly in hydroponics and coco based systems.

Think of an un-flushed plant as sitting in a bath that has not been changed for a few weeks, it may be sitting in toxic mineral build up.


Flushing Toxic Buildup (Mid-Grow Flushing)

A common issue but almost always mis-diagnosed that many hydroponic growers will run into during their first few grows, is a toxic build up and accumulation of mineral salts within their medium. This is rather common for growers that use coco mediums with hydroponic nutrients, allowing a slow creep up of medium EC and huge pH swing as a result, which can be devastating or even fatal to the plant if left unchecked.

Why do I need to flush mid-grow and how will I know when I need to?

For the best and most accurate results when growing using hydroponic nutrients, you should be measuring your run-off from your plants everyday, at minimum once every 3 days.

'Run-off' is the excess liquid that will run out of the bottom of your pot after a feed, measuring this liquid will give you a good idea of what the pH and EC is actually like in your medium. If you are feeding your plants a 1.5 EC, 6.0 pH solution and the run-off is measuring 2.1 EC and 5.3 pH, then your medium is likely in a toxic state to the plant and sitting in an acidic pH environment. This will cause nutrient lock-out and stunt growth, eventually killing the plant over time.

This has occurred because the grower has been feeding too many nutrients to the plant that it was unable to consume before the next feed happened, building up an excess of mineral salts (nutrients) in the medium.

To correct mineral salt build up in the medium, the answer is to flush the pot and medium using plain water to dilute and clean out all the accumulated minerals. To do this, simply flood the medium with plain water and measure the run off, repeating this process until you have a run-off reading in the range you are happy with.

In the case above, you are trying to feed 1.5 EC / 6.0 pH to your plant, but your run-off is reading 2.1 EC / 5.3 pH, you would want to flush your medium with plain water repeatedly until the flush run-off is reading a safe range, such as 0.5 EC / 5.8+ pH. This may take several flushes and lots of water to achieve. If you were to skip the flush and feed this toxic pot with your 1.5 EC / 6.0 pH solution, you would end up increasing the EC in the medium even further into toxic conditions and killing your plant at a faster rate.


The Final Flush (Harvest Flushing)

If you are reading this tutorial because you’re near the end of your flowering phase then follow these steps to ensure you’re not flushing too early.

  • Pay attention to the overall form of the flower and fruit, usually with an 8-week strain, the flowers development starts to plateau around week 6 - 6.5
  • At this time, we massively reduce our nutrient solution concentration.
  • Usually before this transition most growers would have an EC between 1.5-2.0
  • Remove any old solutions and replace with plain water, correcting the pH to 6.0-6.2
  • Most tap water in Australia is between 0.0-0.1 EC
  • Ideal maturation is 0.1-0.3 EC


Coco Flush:

The key here is to flood the pots until the water is running freely out of the base of the pot, you would then allow the plant to naturally dry up the pot itself, then its rinse and repeat for approx. 7-14 days.


Hydroponic Flush:

For systems where the roots are permanently sitting in nutrient solution, such as Deep Water Culture, the flush of these systems are the easiest and fastest, as no build up of nutrients can occur in the medium. Start by removing old nutrient solution from tub/reservoir and fill with plain water at pH 5.8-6.0, the plants would then sit in this water for around 7 days until harvest.

Alternatively, some growers prefer to scale down the nutrient solution strength over a two week period until the EC of their reservoirs reach around 0.5 for the final 3-5 days, simulating that of a downscaling coco flush.


A harvesting tip:

Harvest your plants before the lights are due to come on, this ensures there are no left-over nutrients being circulated through the veins of the plant, remember as soon as light touches them the capillary action re-commences.

Utilising this method will also ensure in maximum terpenoid profile, after a long day of light exposure the terpenoid hydrocarbons evaporate, by harvesting this way you will always have a super aromatic crop!


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Controlling your solution by creating good habits early, for strong, healthy plants and bountiful harvests, it’s not as difficult as it may seem, it’s just getting into the habit. So, it may take a few grows consecutively with mixed results, persevere and you will be quite amazed at what can be achieved.

Most nutrient feed charts talk about weekly feeding, this means in each week there are 7 days, every day, of every week, is a feeding day. Feeding days does not necessarily mean we flood them with a rich nutrient solution, but we must give them something, that could be anything from 1.5ml>150ml>1.5L the point is we must give them something relative to their needs and age.

Most feed charts incorporate cleansing solutions that effectively seek and destroy excess salt accumulation and convert back in a useable form for the plants, if this is a persistent problem for you, I recommend you drop your nutrient dose overall by approx. 30%, technically if plants are fed correctly there should be a minimal EC being withheld in the pot/root zone/tank.

However, if the entire nutrient solution is not changed every 7-10 days you risk toxic accumulation of salts and metals.

The strength (EC) of the nutrient solution may register correctly but if you have just been topping up the existing mix without change, there is no way for you to know what nutrients the EC measurement is comprised of, as EC meters only read the ‘entire value’ of food present, not individual elements. (Elemental tests do exist, but can be quite costly for digital devices and the manual methods can be grossly inaccurate)

For those gardeners growing in pots using coco coir or soil, the best way to maintain an ideal EC without the possibility of build-up is to force run off with each new feed. This practice will ensure any heavy salt and metal accumulation will be removed/washed away.

Another way to prevent nutrient toxicity is to flush your pots/systems every 3rd feed with just plain pH corrected water.

A factor most gardeners do not consider is the depletion of dissolved oxygen, the roots of every plant need oxygen to thrive! No oxygen = nutrient restriction. The plants roots also utilize dissolved oxygen in order to fight anaerobic bacteria’s like phytophthora and root rot.

Never let a nutrient solution sit still or stagnant, implementing air-pumpsairstones and water pumps to keep the water moving will ensure constant oxygen availability. 

Check your nutrient solution every day if you have a tank, not all final solutions are equal:

  • Avoid Dilution
  • Avoid Over feeding
  • Use a Quality Nutrient
  • Change Reservoir Every 7-10 Days


Monitor your plant, observation is key - Remember that the feeding schedule provided is a ‘Guide’ so slight alterations are generally made, thus allowing you to tailor nutrient levels for specific crops. 

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This week's tutorial is a redux of a edition from December 2017

Growing indoors in the hotter months can be quite tricky for growers not reliant on climate control systems have to control this aspect of the grow themselves, using a variety of methods and tricks to reduce the rising temp.

So, let’s jump right into topic which is heat stress and environmental temperature.

Heat stress can cause irreversible damage to plant tissue, light is not the issue here as plants can never have enough light, the problem is the accumulated heat energy that causes the surface temperature of plant tissue to rise so much that the plant are unable to photosynthesise light causing a systematic metabolic shut down.

Heat stress can cause many things to go wrong, in both phases of the plants lifecycle there are different issues associated with this.


Heat stress in vegetation

Leaves can curl upwards and create a canoe type of look, high temps coupled with low humidity can make this symptom even worse.

FIX – Raising the light and reducing the wattage output of your lighting system if it is adjustable, go for par over power in this instance as it’s not the light causing the burn it’s the excess heat energy from the light, also lowering the amount of food you give them is highly recommended as water consumption is a preference on particularly hot days, also as lights are due to go off, a weak foliar spray will help clean the stomata of any dust and will help hydrate locally much faster.


Excess heat to plant canopy can drastically alter the plants leaf surface temperature, which can severely impede stomata function on the underside of the leaf as the stomata on the top are overworking by “sweating” water into the atmosphere to increase humidity and cool itself down, which in turn reduces the amount of carbon dioxide the plant can absorb. 

FIX – Same as above, however if dimming the lighting is not an option and the PPFD readings of your light is exceeding 1000 then Co2 supplementation will be needed to circumvent any potential air restrictions.




The root zone is also affected by the temperature increase, ideally most root zones should be maintained between 18.5c – 22c max! The higher the temp of the medium (substrate) the higher the likelihood of root bound diseases and pathogens. 

FIX – Short of the obvious - Frequent replenishment of nutrient solution, installing a water chiller, making and immersion wort chiller etc. There is a compound (Microbial) that can be added to your nutrient solution beforehand which leaves behind a protective barrier making the roots more resilient to the major temperature swings thus reducing the chance for a fungus or pathogenic attack.


(Don't be this guy, plants don't like scorching hellfire) 

Heat stress in Flowering

“It’s not the end, even though it looks like it!”

Heat stress in flowering can be detrimental to the outcome and quality of your harvest, it is one of the worst things to happen, follow the next few suggestions and you should be able to salvage some of the better aspects of the plants.

Ensure that you do not overwater! Heat stress is not a drought! Do Not spray plants with anything whilst your lights are running. A general rule is never spray in flower unless you have an unexpected mite infestation, in which case you would still spray with the lights off, excess moisture on the plant whilst lights are on and temps are climbing will almost guarantee a scorched crop.

When flowers become heat stressed they result in “fox tailing” which is a stress related type growth, where secondary pistillate flowers actually start forming vertically from the top of the existing flowers. (Note: Some of the newer poly-hybrids can naturally foxtail as an expression from one of the parents.)

FIX: Dimming the lights and raising slightly will not prevent this (fox tailing) from happening but it will lower the amount of heat energy being exposed to the plant canopy allowing the plant to re-direct energy to primary flower growth. Fox tailing occurs much closer to the light and is exposed to the rising heat within the room, install air moving fans to stratify the surrounding air and if the exhaust system you are running is variable in speed I would suggest increasing the volume by an additional 10-25%.


Problems with heat stress impact everything in our environment, if heat stress is present then this stress will affect any variable like hydroponic systems, growing substrates, brain tanks etc..

Heat stress in nutrient tank reservoir’s directly impact EC concentration, EC will rise due the evaporation of water, always pay attention to your brain tanks or reservoirs on particularly hot days, I suggest lowering the EC by 0.5-0.8 and closely monitoring the pH and EC until the conditions have subsided. Understanding that as water evaporates from the nutrient solution, the EC will rise and pH will drop.

Other important factors to pay attention to is vapour pressure deficit (VPD) so, if the humidity is very low (20-30%) and the temperature is very high (29-32c) VPD is high, heat stress symptoms can occur due to low humidity therefore in an effort to cool itself down and increase the ambient humidity the plant will transpire.

If the environment is too high in temperature and too high in humidity, VPD is too low, so you will need to acquire a de-humidifier to lower the humidity and ideally some form of cooling apparatus like a portable air-conditioner, when this happens in the grow room the vapour pressure deficit of the room (VPD) is so low that the plants cannot adequately cool themselves down resulting in wilt and poor stomata operation.

TIP: A Hygrometer will give an accurate temperature and humidity reading, to raise the humidity most indoor gardeners opt for humidifiers/foggers to increase the humidity but they can be quite expensive, fortunately innovation has allowed others to emerge with products that work just as well, for example Integra released the Cargo dry strip which can be hung in your flowering or drying space and will maintain 50-55% humidity for up to 50 days.


So, there you have it lets hope some of these suggestions can help you dial it all in!

Heat stress isn’t any fun (at all), the learning curve is a great one though!

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This tutorial is a revised and updated version of our FAQ about Hydroponics

What is Electrical Conductivity?

Electrical conductivity or EC as it relates to hydroponics is a measure of the dissolved salt content in any given aqueous solution.

To put it more simply EC indicates how the strength of any given nutrient mix you have made up. The more nutrient you add to your mix the higher the EC will be.

EC is the primary measurement used in assessing how much nutrient to give a plant at any given point in its life cycle. As plants grow they require more nutrition to stay strong and healthy, young plants will usually require an EC of between 0.2 and 1.0 where as fully mature flowering plants may require an EC of between 2.0 – 3.0.

For horticultural purposes EC is the most accurate way to measure the concentration of nutrients in your mix however there are other units of measurement relating to this, these are Parts Per Million (PPM), Total Dissolved Solid (TDS) and Concentration Factor (CF).


What is pH?

Potential Hydrogen or PH is a measure of how acidic or alkaline any given liquid is.

Understanding and managing the PH of your nutrient mix is extremely important when growing hydroponically. The PH scale ranges from 0 to 14 where 0 is the most acidic, 14 is the most alkaline and 7 is neutral. Pure water has a PH of 7 whereas lemon juice which is acidic has a PH of around 2 and bleach which is alkaline has a PH of 12.

PH becomes important for hydroponic growers when we start thinking about feeding our plants, as we add different nutrients to our water these nutrients will have an effect on the PH of the mix, some nutrients will raise the PH and others will lower it, the key is once we have everything mixed up and we have ensured our EC is correct we then need to check our PH and adjust it if necessary.

PH is easily adjusted by using a ‘PH Up’ or PH Down’ solution sold at all good hydroponics stores. All plants have a preferred PH range that will ensure healthy vigorous growth, most plants like a slightly acidic range of between 5.5 and 6.5. If the PH of your solution falls out of the required range then the plant will be unable to take up and use key elements from the nutrient solution and thus deficiencies or toxicities will soon appear.

There are some very helpful videos online for those growers interested in learning about the chemical processes behind PH and PH changes however provided a grower knows their plants desired PH range and has the ability to measure and adjust the PH of their nutrient solution everything should be AOK.


What EC should I maintain?

EC (Electrical conductivity) requirements change as the plant grows from seedling into a mature plant. When your plants are young they require less food, so it makes sense that as the plant grows we increase the amount of food to fulfil the plant’s needs.

Seedling requirements: 0.4 – 0.6

Growth/Vegetative requirements: 0.6 – 1.6 EC

Bloom/Flowering requirements: 1.6 - 2.4 EC


What pH should I maintain?

The consensus for pH in a hydroponic system & coco coir is that it should be kept between 5.5 - 6.5 throughout the cycle, ideally in the growth/vegetative phase pH should be maintained at 5.8-6.2 - if the pH fluctuates too much the plant will be unable to uptake specific nutrients, so having the necessary equipment like a pH pen will save a lot of guess work.

When the plants go into the flowering phase consistency is key ensuring the plant has a constant supply of the nutrients it requires, the preferred range in flower is 6.0 - 6.4 as different elements are required in the bloom phase, if this range was lower or higher the plant would be unable to absorb targeted nutrients, thus stifling development and severely impacting the end result.


How long should I run my lights?

The general rule of thumb for vegetating plants is 18 hours of light and 6 hours of darkness, once flowering has begun or the plant is of suitable size to flower you will need to change your photoperiod to 12 hours on and 12 hours off, keeping in mind that once your plants start flowering the darkness cannot be interrupted, if light enters the space when flowering, you could reset the plant to vegetate or even worse, they can mutate which will massively impact the end result. It is not recommended that plants receive 24 hours of continuous light at any time during the life cycle. Many growers will leave their lights off for the final 36-48 hours of their grow to great results.


Does the nutrient solution need to be heated? 

For optimum growth, it is best to maintain your nutrient solution at a temperature of between 18 – 22 degrees (C)

If the room temperature falls below 17 degrees during the dark period, then you will require a water heater. If the nutrient solution does go below 18 the plant can stop growing and go into shock.

If the solution is above 22 for too long it can become the perfect breeding ground for algae, Pythium and a host of other bacterial infections


What causes plants to die?

There can be a number of reasons for this. Firstly, eliminate the obvious things like lack of water, high temperature or a broken stem.

Root diseases are the most common cause of "sudden death" for plants and can cause many problems from loss of yield to complete death. Pythium is the most common disease. Ignoring the basics on temperature control can present quite a nightmare. Always use nutrient conditioners if you reservoir is prone to temperature rises, these formulations mostly contain quaternary ammonium and copper which will help prevent nasty pathogens from taking hold.


What causes the tips of the plant’s leaves to burn?

This is usually caused by overfeeding i.e. giving your plants too high an EC before they are ready for it. It can also be caused by a buildup of salts/food within your growing medium. If you suspect either of these scenarios it’s a good idea to fully flush your plant then go in with a reduced EC.

There are some nutrient deficiencies that can also cause leaf tip burn. Again, if the gardener has themselves a pH and EC meter this is rarely an issue.


What causes leaves to turn yellow?

This can be caused by a number of factors:

  • Low oxygen levels due to lack of aeration or too much water.
  • A nutrient deficiency.
  • The pH is too high/low.
  • The solution is too hot/cold.
  • EC too high/low


All of these prevent the plant from absorbing nutrients in the correct quantities, always use an EC meter and a pH pen to prevent this from happening. It should be noted that towards the end of the flowering cycle it is normal for the lower leaves on the plant to start turning yellow.


Why do plants stretch?

Plants stretch when their light source is insufficient, humidity is too high or they are crowded by other plants.

Lowering or turning up your light, increasing air flow or spacing plants further apart are some good options. 

It should be noted that for 14-21 days after the lights are changed to a 12/12 cycle your plants may ‘stretch’. This is more referring a period of further vigorous vegetative growth and should be anticipated.


What Humidity (RH) should I maintain?

Vegetating/growth: 55-65%

Flowering/bloom: 45-55%

Drying: 45-50%

Curing/storing: 55-68%

Excessive humidity for long periods will create undesirable conditions that are perfect for grey mould to thrive. Grey mould, once started, will quickly spread and affect your entire crop.

Using a hygrometer device mounted on the wall inside your hydroponic grow room will let you know at a quick glance what your humidity levels are. Humidity levels of just above 50% during flower is perfect and should not go above this. It is important to keep nutrient reservoirs covered at all times so that they do not contribute to higher humidity levels.

Humidity levels can be easily controlled as with temperature by using inlet & extractor fans to rid the room of heat or humidity. Generally, it is good to keep your grow rooms clean and dry. This will help prevent any mould problems.


What Temp should the growing room be? 

While the lights are on temperatures should be maintained between 22 and 28 degrees. When the lights are off temperatures are permitted to drop by 5 degrees or so. It is best to avoid large temperature fluctuations in the growing space at all times. If temperatures fall outside the optimum range for too long development can be significantly stifled or worse. Your main tool for regulating temperature and humidity in the grow room will be a quality exhaust fan.


How much ventilation is necessary?

The main purpose of ventilation in a grow room is to expel hot and humid air and to replenish CO2. Finding the perfect balance between optimum temperature, humidity and CO2 can be tricky and thus investing in the right gear from the start is important. A good quality variable speed extractor fan will serve you well. As a general rule, you want an extractor fan that can complete a total exchange of vapour within the grow room every 1 – 3 minutes.


Should I use EC & pH meters?

Operating a hydroponics system without meters is very difficult and it would be very hard to achieve optimum results. Always use meters to attain perfection.


What size reservoir should I run?

Depending on the type of system you are running and the plants feeding requirements.

For ease of control use a minimum of 45 ltrs per/m2 of growing area, less than this requires frequent adjustments.

Some systems like DWC (Deep water culture) actually have the plants growing in a large volume of water and nutrients, this type of system can be plumbed to an external reservoir that will top up your main system as the solution depletes.


Is it necessary to aerate the nutrient solution? 

Aerating the nutrient solution is a good idea. It guards against stagnant water, improves plant health and prevents bacterial infections. Aerating a nutrient solution will last far longer than one that is sitting flat. Generally speaking, if you are running a recirculating hydroponic system or intend to store a nutrient solution for more than 24 hours you should be aerating your nutrient solution.


How long should it take for clones to strike roots?

The time taken to strike roots on clones varies according to the time of the year and the health of the clones and whether the method is manual or assisted About 5-12 days is usual for most manual methods.

Assisted methods include cloning machines that drastically speed up oxygen intake which in turn can force roots to form with 3-7 days.


What is the best water to use?

The best water will have low salts or contaminants. Rainwater is probably best though normal tap water is usually satisfactory and convenient as long as it is under 0.3 EC

Most Australian tap water is valued between 0.0 - 0.3

Reverse osmosis is fast becoming a preferred method as well, the only downside is pH fluctuations (using a pH stabiliser will correct this) and the water after it is cleaned will require re-conditioning with a calcium magnesium additive.


Which type of grow light should I use?

The choice of light used in your grow room will arguably be your most important decision when setting your space. There are several lighting options to consider when building a hydroponics set up. All options have their pros and cons and these should be considered carefully before making your decision.

The most common choices are High Intensity Discharge (HID), Light Emitting Diodes (LED) and Florescent lighting. 


HID lights are the most common grow light used they have been the industry standard for decades now and as a result the price of these lights has become very affordable. They have shown to give gardeners consistent results over the decades when used correctly.

The down side to this option is the colour spectrum for HID lights are quite limited thus you will need to use two separate lamps (globes) for different stages of growth.

During the vegetive stage it is best to use a Metal Halide HID Lamp and then for the bloom stage it is advised to use High Pressure Sodium lamp these lamps should be swapped out for new lamps every 6-12 months.

Often another down side to this option is HID lights run very hot therefor it can be difficult to control temperatures in your growing space. If temperatures exceed 29 degrees in a grow room it can severely affect the quality of the finished product.

A promising new evolution in the HID market has been Light Emitting Ceramic (LEC) fixtures also known as Ceramic Metal Halide (CMH). These new HID lights offer the plants a full light spectrum and run more efficiently than older HID options.

The down sides to these lights are they still produce a lot of heat and they can not be powered by traditional HID ballasts as they require specific low frequency ballasts to operate. 


LED grow light fixtures are becoming more and more common and can offer growers very impressive results due to their wide range in colour spectrums and incredibly efficient energy use.

Unfortunately, due to a large amount of cheap, sub-par LED grow light models flooding the market over the last 5 or so years the true potential of LEDs hasn’t been fully realized by gardeners.

As LED technology improves and the market becomes more savvy there are more companies offering high quality and extremely powerful LED fixtures for all types horticulture.

The efficiency of LED fixtures comes primarily from the fact that almost all the power used by the fixture is converted into light energy as opposed to heat energy which is a huge benefit for growers in warmer climates however growers in cooler climates will have to supplement with heaters.

High quality LED fixtures have the additional advantage of maintaining the same level of light output for up to 10 years.


Fluorescent lighting is a relatively efficient full spectrum lighting option that works best for gardeners raising seedlings, clones and looking after mother plants. These fixtures usually range between 50w and 200w and as such aren’t a great option for later vegetive and flowering growth but will provide young plants with the full spectrum and warmth they require to thrive before being put under a HID or LED fixture.



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This is a guest article by CAN-Fan/Filters

The original article and filter calculator can be found HERE

First off, you’ll want to determine the requirements of your application.  Whether or not you are exhausting (going from a contaminated environment to a sterile environment in only a single pass through the filter) or recirculating, aka “scrubbing” (exhausting the system back into the contaminated space). 

This is important because in an exhaust setting the air only passes through the filter one time so it is imperative that we remove as close to 100% of the contaminate as possible with that one chance. This requires that the contaminant have a certain time in contact with the carbon in order to be fully adsorbed.  Our filters are marked with both exhaust and recirculating ratings for just this reason.  If you are using this system to exhaust, DO NOT exceed the exhaust rating for the filter, the more this rating is exceeded the less contaminant will be adsorbed because the two will not have enough contact time for adsorption to fully take place. 

In a recirculating system, the contact time is not such a crucial number as we are taking contaminated air, filtering it, and releasing it back into what is typically and constantly decontaminated environment.  It is for this reason that it is not necessary to remove 100% of the contaminant in a single pass.  Instead we double the exhaust rating which will reduce the contact time, the goal here is to still remove a large portion of the contaminant but to get raise the cycle rate of air through the filter above the rate of emission from the source.  Now, instead of removing 99.9% of the contaminant in a single pass we are getting closer to 60% but we are getting twice as many cycles through the filter in the same amount of time and over time, reducing the overall build-up of contaminant in the environment.  This is ok because we are not exhausting into a sterile space but instead to a space that is already more contaminated, after the system has run for a few hours, you will notice that the build-up of contaminant has been reduced to only the constant emission.

Recirculating systems can be desirable when atmospheric adjustments have been made to the environment such as the addition of air conditioning or CO2 which exhausting outside can be less efficient and more expensive than leaving the front door open.  Recirculating systems are intended to be used in sealed rooms. 

Once you’ve determined the type of system you need, it’s time to size your space.

Typically for exhaust we recommend a simple length x width x height /3 calculation.  This will give you the amount of air (cubic feet per minute, CFM) that you will need to move to properly ventilate your space allowing for a three-minute air exchange (all the air in the space is exchanged for fresh air every three minutes).  This is the number you will match your filter to.


Room size: 10’x12’x8’ (960 cubic feet)

960 cubic feet / 3 minutes = 320CFM (Minimum recommended CFM to exchange the air every 3 minutes)

For recirculating systems, you can use the same length x width x height but divide by 1.5.  This will give you a high cycle rate while still ensuring the removal of a majority of contaminant with each pass through the filter.

Great, now that you know which filter to use its time to find the fan to pair with it.  Take that CFM target used to find your filter and match it with the closest fan rating.  It is wise to factor in a 10% -25% drop in airflow due to the resistance of pulling through the carbon filter.  Just remember, if you are running an exhaust system, DO NOT choose a fan that will exceed the exhaust rating of your filter.

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Have you ever wondered the mechanism behind how plant drink and eat?

This tutorial is aimed to teach the basic mode of action.

Translocation is the movement of materials from one part of the plant to another.

So how does translocation work internally?

Image Credit: Fuse School

Flushing is an excellent example; When flushing mature plants, the much-needed elements remaining in plant tissues, are now being shifted from the oldest parts of the plant to the newest, (See nutrient mobility) until all elements have been depleted, whilst this is going on you will see a visual of the leaves rapidly losing chlorophyll pigment and expressing others known as carotenoids and anthocyanins. (which are flavonoids)

Xylem, moves Water and food from the root zone through the plant and to the leaves.

Xylem vessels are made up of elongated dense cells that are impermeable to water and have walls containing lignin, a woody material.

Phloem, moves sucrose generated via photosynthesis to the rest of the plant in conjunction with the supply of amino acids.

Phloem vessels are made up of living cells and they transport sucrose & amino acids up and down the plant.


Image Credit: FS - Xylem & Phloem are found in groups called vascular bundles.

Transpiration, what is it?

Transpiration is the evaporation of water in plants, plants transpire primarily at the leaf site, the leaf stomata are opening and closing for the passage of CO2 (Carbon Dioxide) and O2 (Oxygen) during photosynthesis. When a plant is over-transpiring, the stomata closes as a way of reducing transpiration.

So, in a nutshell transpiration is a plants way of maintaining internal temperature.

The higher the SVP (Saturation vapour pressure) the less plants will transpire, this is simply because the humidity is high, if humidity is too low then the plant will to transpire until the ideal SVP is achieved. If the humidity stays too high the plant will lose turgor and become limp.

The ideal (RH) humidity % for plants: 
  • Germination - 76-100%
  • Vegetation - 60-65%
  • Flower – 50-56%


Usually when any grower is starting from scratch the majority do not have the luxury of climate control and are reliant on ambient conditions. So growing in a grow tent or room from seed always present the same issue, we have no bio-mass within the environment, and for young seedlings this is critical timing, if nothing is corrected within the environment the plants leaflets will ‘canoe’ or curl inwards due to them over transpiring to achieve the correct SVP.

This is quite an interesting topic to leave open for the comments, my explanation is quite basic so if more complex detail is needed for whatever reason, please comment below.

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Fungus gnats are small flies very similar to fruit flies that belong to part of the Mycetophilidae and Sciaridae families.

They feed on decaying organic matter, fungi and plant roots (especially damaged roots making plant much more prone to diseases).

Fungus gnats are particularly dangerous to plants as they can also carry diseases such as Pythium on their bodies and have the ability to transfer it from plant to plant.

The life span of a fungus gnat consists of about 3-4 weeks depending on the conditions of the environment. Fungus gnats love, damp moist (overwatered) substrates, as they breed extremely fast in these conditions (up to 300 eggs in an adult’s life) and benefit from high humidity, so the threat of an infestation in the vegetation phase is more likely than in flower given that the humidity is at the correct setting.

Fungus gnats have 4 stages of life:

  • Egg
  • Larvae 
  • Pupae 
  • Adult


The eggs will hatch after about 3-6 days, hatching little larvae (Translucent maggot looking things)

The larvae feed on the fine root hairs of the plant and will do significant damage to nutrient absorption (the plants ability to uptake nutrients) if feeding on a seedling/cutting or an unestablished plant meaning there will be an insufficient amount of nutrients available for healthy growth.

Fungus gnats are pretty easy to control if the infestation isn’t too bad, but if infestation is bad, your fruits/flowers will act as sticky traps, leaving tiny gnats stuck to your flowers, which can cause things like bud-rot, mould and foul odours. Not to mention an unusable crop.

When treating such infestations, the current range of available products have generally been insufficient in their attempt to remove the problem. So, if avoiding harsh chemicals is a priority when treating the problem there is not much available that doesn’t impact other important growth factors.

Finally, though there is a product (Triple R, by Lost Labs) that is organic, restores the much need elements the fungus gnat removes during attack. So, not only does it remove the adult fungus gnats it completely destroys the larvae, replenishes the root zone and then restores ecological balance within the root-zone thus allowing the plant to experience minimal shock and carry on its reproductive cycle. 

If you have fungus gnats you can’t just leave it a day or two and then attempt to fix the problem, by that stage the number of larvae bred makes it very much an uphill battle to remove them.

Keep an eye out for a new product by Lost Labs; Triple R. Coming soon to A-Grade.
Remember that prevention is better than cure.

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