Hydroponic Additives & Supplements

What an additive does that a base nutrient does not

A complete base nutrient carries NPK and the trace elements, balanced for a growth stage, and can finish a crop on its own. An additive is incomplete on purpose and does one job hard — raise calcium and magnesium, supply silicon, drive PK through peak flower, feed the biology around the roots, or strip the system before harvest.

That is why additives stack and base feeds do not. Which bottles you need hang on water, medium and light, not on the label.

Our range of additives and supplements

Cal-mag and secondary minerals

The gap a base feed most often leaves, and the first check when new growth pales or leaf edges crisp. The cal-mag collection runs Athena, Canna, Flairform CMX, FloraMax Ca-Mg-Fe, Green Planet Pro Cal, Med Tek and Plant Mechanics Super N+, from 250mL through to 18.9L.

Silica

One word, two different bottles. Silicate products in the silica collection — Growth Technology GT Silica, Cyco, FloraMax, Flairform Silika Majic, Hy-Gen Budlink — come in litre bottles, dosed by the millilitre. Mono-silicic acid concentrates such as Plant Mechanics Super Si and Bio Diesel Pathway 40% come in 100mL bottles, dosed in drops. Do not carry one dose rate across to the other.

Flowering, PK and bud boosters

The biggest group here. Flowering additives start with straight PK lifts — Canna PK 13/14, Green Planet PK Spike, Athena PK, Cyco Potash Plus — then resin and carbohydrate products like Green Planet Rezin and FloraMax Resin-XS, then House & Garden Top Booster, Shooting Powder and Atami Bloombastic.

Vegetative and grow-stage additives

In veg the job is leaf and stem, not flower. Grow additives include Professor's Grow Fast and Go Green, Cyco Grow XL, FloraMax Growth-XS, Plant Mechanics LED Fuel, and Growth Technology's single-element liquids — Nitrogen, Potash, Phosphorus, Iron and Trace Elements — which correct one element without moving the rest of the feed.

Root stimulants and propagation

These go in at transplant or into a cloner. The root stimulators include House & Garden Roots Excelurator, Canna Rhizotonic, Growth Technology Rootzone and Clonex, Atami Rootbastic, FloraMax Root-XS and Cyco Ryzo Fuel.

Microbes, enzymes and system cleaners

This side is biology, not chemistry. Microbes and beneficial bacteria covers mycorrhizal inoculants (Xtreme Gardening Mykos, Plant Success Great White, SNT Mycobiome), bacterial products (Impello Tribus Original, Mammoth P, BBA Max Roots, Azos) and trichoderma, plus enzymes — Canna Cannazym, House & Garden Multizyme, Cyco Zyme.

Foliar sprays and soil amendments

Not every additive belongs in the reservoir. Foliar sprays — Optic Foliar Transport and Switch, Growth Technology GT Foliar Spray, Accent Green-Up, Bloom Florigen — go on the leaf. Soil additives go into the medium: SNT worm castings and insect frass, De-Ozzy soil conditioner, BIOCARBON biochar in 3L, 9L and 25L bags.

How to choose an additive

1. Fix the deficiency before chasing the yield. A cal-mag or silica gap costs more than a bloom booster returns. Get the base feed right first.
2. Match it to your medium and your water. Coco and rainwater lift cal-mag demand; soil on hard tap water often does not. Enzymes and cleaners belong in recirculating hydro more than in hand-watered soil.
3. Read what your base feed already contains. Several two- and three-part sets already carry a PK lift or extra calcium. Stacking another on top is how lockout happens instead of bigger flowers.
4. Add one at a time. One new additive per run. Three at once leaves you guessing which one did the work.
5. Check the size ladder before you commit. Most lines here run 250mL, 1L, 5L and 20L; Athena runs 0.9L, 3.8L and 18.9L. Trial in the small bottle and step up once it earns a place.

Where to start

Most first-time problems settle with three bottles: a cal-mag, a silica, and a root stimulant. Add a flowering booster once those are settled. Still choosing a base feed? Start with the full nutrient range and The 5 Best Hydroponic Nutrients Australia. Yellow Leaves on Plants? covers the deficiencies these additives are usually bought to fix; Organic vs Synthetic Nutrients covers the organic-versus-mineral choice.