THC Nutrients Australia

THC Nutrients, Total Horticultural Concentrate, is one of Australia's most respected domestic hydroponic nutrient brands. This guide covers who THC is, what makes their formulas different, and a full breakdown of every product in the range with the key ingredients and how they actually work.

Who Is THC Nutrients?

The company has built its identity around three principles: extreme concentration, ingredient purity, and rigorous batch testing. THC Grow A+B and Bloom A+B require just 2ml per litre of each part, meaning a 1L A+B set treats 500 litres of nutrient solution. THC's approach to formulation uses only carefully balanced blends of the finest main and trace elements. The company sources pharmaceutical-grade mineral inputs rather than industrial agricultural-grade alternatives that many lower-cost nutrients rely on. The result is nutrient solutions that remain stable across a wide pH range, resist salt buildup in the root zone, and deliver measurable improvements in nutrient uptake.

THC Grow A+B: Base Vegetative Nutrient

THC Grow A+B is the foundation of the THC system for the vegetative stage. Key ingredients include macro elements (N-P-K) where nitrogen drives rapid shoot and foliage development, fulvic acid which significantly improves the plant's ability to absorb and utilise the nutrients being fed, and a full trace element profile including iron, manganese, zinc, copper, molybdenum, and boron. Dose rate: 2ml per litre. Compatible with all substrates and growing methods.

THC Bloom A+B: Base Flowering Nutrient

THC Bloom A+B transitions plants into full flowering production. The Bloom formula shifts the NPK ratio to prioritise flowering, fruiting, budding, and aroma development. High phosphorus and potassium drives flower initiation, bud development, oil production, and dense flower structures. The same fulvic acid technology from Grow is carried through into Bloom. Dose rate: 2ml per litre. Use from first signs of flowering through to the final pre-flush week.

THC Coco A+B: Complete Coco Coir Nutrient

THC Coco A+B is formulated from the ground up for the specific nutritional demands of coco substrate. Elevated calcium is built directly into the A+B formula at levels matched to coco's natural tendency to bind and retain calcium ions. Elevated magnesium addresses coco growers' tendency to see interveinal yellowing even at correct EC levels. Boron is included at calibrated levels to drive calcium uptake, allow glucose flow to the roots, and reduce fruit drop. The advanced combination of grow and bloom nutrients in a single A+B mix that runs throughout the full life cycle makes THC Coco genuinely user-friendly without sacrificing professional performance.

THC Cal-Mag: Calcium and Magnesium Supplement

THC Cal-Mag is a concentrated calcium and magnesium supplement designed for LED grow environments, coco cultivation, and reverse osmosis water users. In LED grow rooms, plants transpire less than under HPS, reducing the passive uptake of calcium through the transpiration stream and creating a supplementation requirement even when base nutrients contain calcium. RO water users are particularly vulnerable as reverse osmosis strips both calcium and magnesium from source water. Use THC Cal-Mag as a supplement to your base nutrient program rather than as a standalone feed.

THC Silica: Potassium Silicate

THC Silica delivers highly bioavailable potassium silicate. Silicon is deposited in epidermal cell walls where it forms a physical barrier that increases structural rigidity, reduces water loss through transpiration, and creates a first line of defence against pest penetration and fungal spore germination. Add THC Silica before other nutrients, as it raises pH and should be added first to avoid precipitation reactions with phosphorus or calcium.

THC Roid Flower Enhancer

THC Roid is a performance flowering enhancer formulated to stimulate size, quality, quantity, weight, and potency. High phosphorus and potassium drives the mid-to-late flowering phase where cell expansion, bud density, and resin production are determined. Additional bloom stimulants activate the enzymatic pathways responsible for terpene and essential oil biosynthesis. Use THC Roid from mid-flowering through to the week before flush.

THC Eksit: Final Stage Bloom Booster

THC Eksit is the final stage flowering booster. According to THC's official product documentation, Eksit generates extra yield of up to 30 percent by triggering an extra bloom swell at the end of the natural flowering cycle. Late-stage flowering triggers activate the plant's natural ripening cascade. Introduce THC Eksit in the final two weeks of flowering alongside a reduced dose of base nutrient. Do not use Eksit past the point of initiating your flush.

THC Reskue: Plant Recovery Formula

THC Reskue addresses chlorosis (yellowing), environmental stress, and nutrient lockout. Chelated micronutrients are bound to organic molecules that prevent them from reacting with other nutrients in solution and becoming unavailable. pH buffering agents help stabilise root zone pH during stress events. Use THC Reskue at the first signs of yellowing, wilting, or growth stall.

THC Rhizo Shield: Root Zone Defence

THC Rhizo Shield is a natural microbial inoculant that introduces and supports beneficial microbial populations in the root zone that compete directly with harmful pathogens including the bacteria and water moulds responsible for root rot. Use Rhizo Shield as a preventative from early vegetative growth through to mid-flowering, particularly valuable in recirculating systems, DWC, and NFT where root zone pathogens can spread rapidly through the entire system reservoir.

Building a Complete THC Nutrient Program

Seedling and early veg: THC Grow A+B at 25 to 50 percent dose, THC Rhizo Shield, THC Silica. Full vegetative growth: THC Grow A+B at full dose, THC Cal-Mag (LED or RO grows), THC Silica, THC Rhizo Shield. Transition and early flowering: Switch to THC Bloom A+B, maintain THC Silica and Cal-Mag, continue Rhizo Shield. Mid flowering: THC Bloom A+B, THC Roid, THC Silica, THC Cal-Mag. Late flowering: THC Bloom A+B at reduced dose, THC Roid, THC Eksit introduced. Final weeks: THC Eksit with plain pH-adjusted water. For coco growers, replace THC Grow and Bloom with THC Coco A+B as the base throughout the full cycle.

Shop the Full THC Range at Apex Grow

Apex Grow stocks the complete THC nutrient range with Australia-wide shipping from Melbourne, Victoria. Questions about which THC products suit your setup? Contact the Apex Grow team at hello@apexgrow.com.au and we will help you put together a program for your specific grow method, substrate, and stage.

Building Your THC Nutrients Order

For a coco setup, the core order is the THC Coco A+B plus THC Cal-Mag, since coco needs that calcium and magnesium buffering the base nutrient alone doesn't fully cover. For other media, the standard THC Grow and Bloom A+B is the base to start with. If you're chasing yield rather than just running a base feed, add THC Roid through mid-flower and THC Eksit as a finisher, both are concentrated enough that small bottles go a long way.

Frequently Asked Questions

What is the dose rate for THC Nutrients?
THC Grow and Bloom A+B is dosed at 2ml per litre of each part, making it one of the most concentrated nutrient programs available in Australia. At this dose rate, a 1L A+B set treats up to 500 litres of nutrient solution, giving it a very low cost per litre of made-up feed despite its professional-grade formulation.

Is THC Coco A+B different from THC Grow and Bloom A+B?
Yes. THC Coco A+B is formulated specifically for coco coir growing with elevated calcium and magnesium built in. THC Grow and Bloom A+B is designed for hydroponic systems and soil where calcium and magnesium levels are managed separately or provided by the substrate. Using THC Coco removes the need for separate Cal-Mag supplementation in most coco setups.

When do I use THC Roid vs THC Eksit?
THC Roid is used from mid-flower through to the week before flush, supporting bud density and resin production throughout the main flowering period. THC Eksit is a final-stage booster used in the last two weeks before harvest to trigger an additional bloom swell. They are designed to be used sequentially, with Roid through flowering and Eksit as the closer, rather than simultaneously.

Why do I need to add THC Silica first before other nutrients?
THC Silica is a potassium silicate product that raises pH when added to water. If added after phosphorus or calcium-containing nutrients are already in the reservoir, it can cause precipitation reactions that lock nutrients out of solution. Adding Silica first to water before any other nutrients prevents this and ensures everything stays in solution properly.

Can I use THC Nutrients in DWC and recirculating systems?
Yes. The full THC range is compatible with DWC, NFT, recirculating drip, ebb and flow, coco run-to-waste, and soil. The highly concentrated mineral inputs dissolve cleanly and are formulated to remain stable in recirculating systems where nutrient concentration builds over time between reservoir changes.