The FAB Nutrients Guide: Nutrition For Your Plants

Feeding Your SoulSoil

Much like humans, plants need nutrients and food; and cannabis is no exception! The ‘right nutes’ can make all the difference to your indoor cannabis grow.

So, what are the best nutrients to give your cannabis plants in Australia? Well, that depends on a few factors.

Are you doing an all-organic grow? Is it a hydroponic or coco coir setup, or are you just using straight-up potting mix? Even in spite of all this, the most commonly used nutrients are:

Nitrogen (N)
Phosphorus (P)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Sulphur (S)

nutrients nutrition graphic

When growing hydroponically, you’ll be growing without soil.

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Typically, you’ll be using a substrate, instead; like rockwool, clay pebbles, coco coir, or some other sort of mix. Most indoor cannabis is grown hydroponically; even if they’re grown in buckets or pots. Often, they’re still watered by hand… ‘hydroponic’ has to mean a fully automated pump/water irrigation system!

Typically, nutrients for hydroponic cannabis are delivered in liquid form. These nutrients need to be diluted. Too much will kill your plants!

Nutrients are typically split into two types: Part A and Part B. This is because different amounts of certain nutrients are required for different times within the plant’s life cycle.

Products marketed as “grow” solutions are high in Nitrogen (N), which make it excellent for vegetative growth. Products marketed as “Bloom” are high in Phosphorus (P), which help with flower development.

You need to be very careful when mixing up your hydroponic nutrients! Start with lower amounts, and slowly up your dosage to full strength.

How Much Should I Use?

That really depends!

Certain strains can handle more nutrients than others; and the various nutrient manufactures out there have different guidelines. Be sure to check out the label of your nutrients, and go to the producer’s website to learn more.

Here, we’ll cover the General Hydroponics ‘Flora’ range. We’ve had personal experience with it – with stunning results.

This is ultimately what we recommend. More seasoned growers will typically hunt out more interesting and exotic nutrients, or go for an all organic solution!

For around $120 (including delivery), you can get yourself the complete range of nutrients needed for growing hydroponically:

1 x General Hydroponics Flora Grow – 946ml
1 x General Hydroponics Flora Bloom – 946ml
1 x General Hydroponics Flora Micro – 946ml
1 x General Hydroponics CALiMAGic – 946ml

Because we did a hand watering grow, we employed a “Drain to Waste” nutrient solution. This means: when you water your plants, you are allowing for 5-25% water runoff after each water. After each feeding, you’re going to be watering with just plain adjusted pH (5.5 – 6.5) water.

When adding your nutrients to your water mix, it’s import to add them all individually to the watering can or bucket, as mixing them can cause some minerals to become unavailable to the plant. So start with FloraMicro in a cup of liquid, then mix it into the watering can. Then go ahead and do the same with FloraGro and/or FloraBloom, then finally the CaliMagic.

Click the image below to view General Hydroponics Drain to Waste feeding chart.

The watering can/bucket is measured as a gallon – or 3.79 Litres. The feeding amounts are measured in millilitres. To achieve accuracy, use a syringe. You’ll be able to grab a couple from your local chemist with no issue.

You can also find out more information on the General Hydroponics FAQ page.

Ideally, apply your nutrients as such throughout the plant’s life cycle:

Vegetative Stage / Early Flowering Stage:

High levels of Nitrogen
Regular levels of Phosphorus
High levels of Potassium

Flowering Stage:

Low levels of Nitrogen
Medium to high levels of Phosphorus
High levels of Potassium

This is a guide only. Individual breeders may have other recommendations for feeding schedules… so, be sure to research the seeds you buy! Auto-flowering seeds, for example, swap to flowering later in life, and need fewer nutrients throughout their whole life cycle.

Aptus Plant Tech Nutrient Line – Feeding Your Plants

The Aptus Plant Tech series is another great option for hydroponic growers with static reservoir setups.

Use your Facilitator throughout your grow. As the primary nutrient transporter and promoter of plant cell strength, it’s essential to the success of your grow.

Silicic acid is a common nutrient facilitator. It’s a fast bioavailable form of silica in a polymer form. It separates into available monomer form when diluted in water. After a few days, it will begin to become an unavailable polymer again.

An optional step is to spike your nutrient levels for a few feedings during first 2-3 weeks of flowering. This will minimise vertical plant stretch in the preflower stage.

Always add to your static reservoir first. Only make up 2-3 days of nutrients at a time. Do not contaminate your bottle with measuring instruments – pour out your bottle first, then measure.

‘Startboost’ is primarily for vegetative stage. It’s an organic nitrogen source; most effective as root drench, rather than a foliar spray.

Startboost contains nocturnal beneficials. You can use it during bloom, following a heavy flush, to reinnoculate your medium – with no ill effects.

Use this set throughout vegetative stage to increase rapid root development. It’s not recommended to use broad spectrum microbial sources with Startboost. Startboost will create gunking in the reservoir if present for longer than 2-3 days per mix

Ecozen should be used throughout the growing process. It’s also used as a flushing agent in your final week.

Ecozen is an enzymatic product that stimulates microbial life. Handfeed your plants with Ecozen once weekly at double rates (with Calimagic +/- Mammoth P). Feed immediately after mixing.

You shouldn’t add Ecozen into your reservoir with any other nutrients, as it becomes highly unstable after 24 hours.

Mass Boost is primarily for flowering, in this feed schedule.

Mass Boost is an organic mineral Ca / Mg booster mixed with L-amino acids. It is designed to be used throughout vege + spiked in flower, at certain points. You should mix Mass Boost in your reservoir before adding other Aptus products (particularly ‘Peak Boost’).

This guide uses Calimagic, instead – but you can replace Calimagic with Mass Boost in the reservoir for flower on weeks 3,5 and 7. Cannabis has a need for Ca that speaks around week 3-5 of flowering, as the plant is growing, stretching and producing new plant matter.

Going for 0.2-0.6EC ontop of RO water as CaMg (Calimagic)

Bloomboost is primarily used throughout flowering.

Bloomboost is similar to Cannaboost in effect and use case. You should use this throughout flower (from the start of week 2) until flush. Increase your use slowly over flowering stage.

Bloomboost contains beneficials + carbohydrates to inoculate your medium. Use with other broad spectrum microbial products is not recommended.

Mammoth P can be used alongside Bloomboost given once weekly with Ecozen flush @ 0.16mL/L throughout grow… though, this may not have the same positive effects compared to other programs.

This product will create gunking in the reservoir after 2-3 days, similar to Startboost… watch out!

Peak Boost is an Organic P supplement for early-to-mid flowering stage.

Use Peak Boost at the start of week 2, to the end of week 6 of flowering. The idea is to increase use of this supplement until flowers have formed and lengthened. Once you’re ready to start main bulking, you can wind this one down.

For longer flowering varieties (10 weeks +), it’s best to stop use completely at least 3-4 weeks before your expected chop.

Finaleboost is an organic K supplement for mid-to-late flowering stage.

This is a Potassium and Sulfur mix with a large range of use. You should apply this supplement between week 5 until the end of week 8, at the very minimum.

Start small with this supplement, and work your way up. Some cultivars will happily eat up to 3x the amount of Finaleboost, compared to others. You can start earlier and use for longer in your longer flowering varieties.

Aptus Custom Grow Schedule


*All nutrients added to nutrient reservoir… except for Ecozen, which is separately hand watered in weekly, as it will cause significant issues in a res after 24hrs. Calimagic (low dose) can also be hand watered in once weekly with the Ecozen, as well as Mammoth P in flower (+ vege)
Weekly inoculation with Mammoth P at 0.16 mL/L or soil rates should keep optimal rhizosphere in flower. This can be done up to twice weekly, for some plants.
*Use a recirculating pump, but not an airstone – as excessive oxygenation will cause gunking with certain organics. Increase pH instability in the res, and potentailly negatively affect microbes in your res (Startboost/Bloomboost)
*Add Facilitator, Calimagic, Canna coco a+b, Massboost (use this OR Calimagic, but never both), then add the rest of your stuff.
*use a pH solution before adding Startboost and Bloomboost.

Your culture should hold fairly pH stable for at least 24hrs with RO water, pH nutrient reservoir once daily optimally. Always measure EC in, and EC draining out, ideally daily, and adjust feed accordingly

*It’s recommended to mix up 2 days worth of nutrient solution for the reservoir at a time.
*For maintenance foliar spray, use Fascilitator @ 1m/L + Mass Boost @ 2mL/L +Startboost @ 1mL/L once weekly, during your lights-off period during vegetative stage.

*For N or Ca/Mg deficiency, use once-off foliar spray, Fasciltator @ 1mL/L + Mass Boost @ 4mL/L.

For plants with longer maturation periods than 9 weeks, it is best to start the Finaleboost transition earlier, and build up to Finaleboost slower.

It’s recommended to flush your medium whenever EC out is higher than EC in, or whenever nutrient lockout is starting (ie visible leaf damage). Flush plant with RO water till at least below input EC… ideally closer to half. Then, apply flush solution of Calimagic + Ecozen (+/- Startboost and Mammoth P)

*Optional use of Startboost and Mammoth P during an EC correction flush to reinoculated medium at any period during vege/flower. The more RO water needed to flush EC down, the more the use of Startboost +/- Mammoth P for final flush feed is recommended to reinoculated medium

What About Organic Nutrients?

If you’re asking about organic nutrients, you probably want the tastiest, best smelling buds around!

Organic nutes are ideal for the plumpest buds, but require a little more work to adjust and use. They’re utilised in hydroponic setups without any static reservoir, using the “Drain to Waste” method.

Organic nutrients have the potential ruin your water with bacteria and other icky things. Chemical nutrients are known to help make cannabis grow quicker.

Many people wonder if organic nutrients are actually better for their cannabis… they certainly do have their benefits. Some people believe they get more fragrant buds from using organic nutrients. It’s all-natural; which could be important to you, if you’re growing in an artificial environment inside your home.

Make sure you don’t use organic nutrients for a regular hydroponic setup. Organic nutrients can spoil the water in your reservoir with bacteria or overgrowth of organisms. Chemical nutrients increase the potency of your buds, and are generally the way to go for a regular hydroponic setup.

It’s possible to buy organic nutrients from the United States. It works out to around $200 for “General Organics Go Box”, which is quite expensive! These are about half the size of the General Hydroponics bottles.

If you’re after organic nutrients, though… this may be your best – and easiest – bet.

For incredible organic soil, check out Easy As Organics!

They offer a rich soil which you only need to water; meaning, there are no nutrients required throughout its growing cycle.

Use the code FABEAO2020 for 20% discount on all their Water Only Soil.

Speaking of soils…

Nutrients in Soil

Here’s an idea: go look for some organic worm juice.

You can find this around locally on Gumtree and/or the Facebook marketplace, as well as some online stores. We’ve stumbled upon Craig Campbell’s Worm Juiceon Facebook, and have found it to be excellent. He is quite helpful to chat to; he will even mail it right out to you, if you ask him!

In regards to using nutrients in soil, you’ll need to check what soil you are using and whether it contains nutrients. If it’s “super soil” – which is basically soil with compost mixed through it – then you may not need anything additional.

Growing in soil is generally a lot easier. Just as if outside in the garden – the plants will grow like wild. Well, maybe a liiittle slower… but they’ll do it without as much help.

The most important thing with soil is knowing how to correctly administer water. It’s also possible to add hydroponic nutrients to your soil… but be sure to use a very low dose, to begin with! This is not an approach recommended to beginners… you could ruin your plants, doing this.

A good organic soil is great for those who don’t want to bother too much with nutrient mixes. Using hydroponic nutrients and coco coir/perlite for your soil makes for an easy process, for a beginner grower. The sheer versatility in options is part of why growing cannabis may come to be the next great Australian pastime!

Main Article: A Guide for Growing Cannabis Indoors in Australia

Joe Lagrasso

Author: Joe Lagrasso

Joe is a dreamer, entrepreneur and an all-around good guy. He wants to connect the Australian Cannabis community from businesses to consumers.

Joe Lagrasso
Joe is a dreamer, entrepreneur and an all-around good guy. He wants to connect the Australian Cannabis community from businesses to consumers.


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[…] Well, first thing’s first. You need a water can! You can pick one up in Bunnings, of course. I recommend grabbing at least a 9 litre watering can. Not too big, but not too small; your plants need a lot of water! Next, you need to know about how to feed your plants nutrients through the water. Read our nutrient guide for more. […]


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