Hydro Roots

Plagron Hydro Roots: Root Stimulator for Hydroponic Grows

Plagron Hydro Roots is a mineral root stimulator with an NPK of 0:20:0, formulated exclusively for hydroponic systems. Unlike organic root boosters that can clog drippers and cloud your reservoir, this phosphorus-and-boron formula keeps your nutrient solution stable and clean while driving serious root development below the waterline. At 1 ml per litre, a single 100 ml bottle covers up to 100 litres of nutrient solution — concentrated enough that most small-tent growers can run it from seedling through early flower on one purchase.

Why This Root Stimulator Belongs in Your Reservoir

Root development in hydro requires direct mineral intervention because there is no soil microbiome to help nutrient exchange. Your roots are exposed, suspended in solution or sitting in an inert medium — there's no mycorrhizal network doing the heavy lifting. If root architecture is weak, nutrient uptake suffers, and you'll see it in stunted growth, yellowing leaves, and underwhelming yields long before you reach flower.

This product tackles the problem with a straightforward approach: 20.47% phosphorus drives root elongation and cell division, while 0.023% boron plays a role in the enzymatic processes involved in nutrient absorption. According to Plagron's own product documentation, the result is more secondary roots, thicker root hairs, and a denser root mass overall. We've seen growers pull plants out of net pots and be genuinely surprised at the density down there after a few weeks of use.

The honest limitation? It's a root stimulator, not a miracle worker. If your pH is swinging wildly or your water temperature is sitting above 24°C, no additive will save you from root rot. Get the fundamentals right first — this product amplifies a good setup, it doesn't rescue a bad one.

How It Compares to Organic Root Stimulators

Mineral root stimulators like this one maintain reservoir clarity and stability, while organic alternatives introduce compounds that can foster unwanted microbial growth. If you're running a recirculating DWC, NFT, or drip system, organic root products risk clouding your solution and leaving biofilm on pump components. Plagron designed this formula without organic elements specifically to avoid those issues. It dissolves cleanly, won't leave residue on your lines, and plays nicely with other mineral nutrients in your feed schedule.

For soil or coco growers, Plagron makes a separate product — Power Roots — which includes organic compounds suited to those media. If your roots live in water, this is the one to buy.

Specifications

The table below lists the key technical details as stated on Plagron's official product label and feed chart.

How to Use Plagron Hydro Roots

Dosage is 1 ml per litre of nutrient solution, added after your base nutrients and before pH adjustment. Follow these steps for best results:

1. Shake the bottle well before each use — the phosphorus can settle at the bottom, and you want a consistent concentration every time.
2. Prepare your nutrient solution as normal in your reservoir or mixing container.
3. Add 1 ml per litre of water. For a 20-litre reservoir, that's 20 ml. A single bottle covers 100 litres total.
4. Stir or circulate the solution to distribute evenly.
5. Check and adjust your pH after adding this product — the high phosphorus content will shift your pH downward. Aim for 5.5–6.5 depending on your system and growth stage.
6. Use this solution with every watering from the start of your grow.
7. Stop at the beginning of the third week of flowering. By this point, root architecture is established and the plant's energy shifts to bud production.

From Our Counter: What We've Actually Noticed

The bottle feels deceptively small at 100 ml, but at 1 ml per litre, it lasts longer than you'd think — especially if you're running a compact system with a 10–20 litre reservoir. The liquid itself is clear and thin, almost watery, with barely any smell. It mixes instantly without the cloudiness you get from some organic alternatives. If you've ever had to scrub biofilm out of airline tubing, you'll appreciate that.

One thing worth mentioning: this formula adds a meaningful amount of phosphorus to your feed. If you're already running a PK booster or a base nutrient that's heavy on P, keep an eye on your overall phosphorus levels. Overloading phosphorus can lock out zinc and iron, and you'll see it as interveinal chlorosis on new growth. We had a customer come back last month convinced his plants had a disease — turned out he was stacking this with another high-P additive and locking out iron. Dialled back the booster, problem solved within a week.

Another honest note: we occasionally get asked whether this product is worth the cost compared to just running a higher-phosphorus base nutrient. In our experience, the boron component and the specific phosphorus form Plagron uses here do seem to produce visibly denser root mats than simply bumping P in your base feed. That said, we can't point to independent peer-reviewed studies confirming this — it's based on what we see from customers and our own test grows. Take it for what it's worth.

Setting Up a Complete Reservoir Feed Schedule

A root stimulator works best as part of a balanced feed programme rather than in isolation. According to Plagron's official feed chart for hydroponic cultivation, this product slots in alongside Hydro A&B base nutrients from day one. During the vegetative phase, you'd typically run the base nutrient plus this root stimulator at every reservoir change. Once you transition into flower, Plagron recommends adding Power Buds to the mix while continuing the root formula through week two of bloom.

The data from the Beckley Foundation's broader research into plant nutrient uptake mechanisms — while not specific to this product — confirms that phosphorus availability during early growth stages has an outsized impact on root-to-shoot ratios. This aligns with Plagron's recommendation to front-load root stimulation and taper off once flowering begins. For growers looking to order a complete Plagron hydro lineup, pairing this with Hydro A&B and a reliable pH meter covers the essentials. An EC meter is equally important — accurate readings make the difference between a good grow and a great one.

Who Should Buy This Product

This product is best suited for hydroponic growers running recirculating or drain-to-waste systems who want a clean, mineral-based root stimulator that won't compromise reservoir hygiene. If you're growing in soil or coco and want root support, look at Plagron Power Roots instead — it's formulated for those media with organic components that actually benefit a living substrate.

If you're new to hydro and wondering whether a root stimulator is worth adding to your feed schedule: yes, but only after you've nailed the basics. A stable pH between 5.5 and 6.5, water temperature between 18–22°C, and adequate dissolved oxygen matter more than any additive. Once those are dialled in, this formula gives your root zone the push it needs to develop the kind of dense, white root mass that translates directly into bigger, healthier plants above the waterline. You can order it here at Azarius alongside everything else you need for a complete hydro setup.

Frequently Asked Questions

Last updated: April 2026