Plagron - Hydro A&B

A highly concentrated two-part bio-mineral base nutrient for inert substrates, for growth and bloom. 2.5 ml of A per litre of water, 1 to 400, plus the same amount of B. Usable in drain-to-waste and recirculating systems alike.

DTPA chelates: why this holds up when your pH drifts

Trace elements such as iron, manganese and zinc are awkward guests in a nutrient solution. They precipitate or become unavailable as soon as the pH moves outside a narrow band, and then the element is in your tank but not in your plant.

A chelate is the answer to that: a wrapper around the metal that keeps it in solution. Not all chelates are equally strong, and that is precisely where this bottle sets itself apart. Plagron use DTPA, which keeps its grip across a wider pH range than the lighter variants.

What that delivers in practice shows up at the two moments where hydro growing really goes wrong. If your pH climbs or drifts, the trace elements stay available instead of dropping out exactly when you have not noticed. And if your root zone is cold, for instance in a system standing on a concrete floor or early in the season, uptake keeps running where it would otherwise stall.

That makes this above all a nutrient for conditions that are not perfect. Anyone with a tightly controlled room will notice it less; anyone dealing with swings is buying margin here.

A and B, always in equal parts

Both bottles are declared separately and they do different work. A is NPK 5-0-2, with calcium nitrate, magnesium nitrate and potassium chloride: all of the nitrogen is present as nitrate, plus 2% potassium. B is NPK 2-4-9, with 4% phosphorus pentoxide and 9% potassium oxide.

That is also why they are supplied separately. Calcium from A and phosphate from B form an insoluble compound when undiluted, and that settles on the bottom of your tank instead of going to your plant.

Always use A together with B in equal parts. Give only A and your plant misses all of its phosphorus; give only B and it misses its calcium and most of its nitrogen.

Drain-to-waste or recirculating

This nutrient suits both: systems where the water drains away after the feed, and systems that pump it back to the tank. That is not a given, since there are hydro nutrients built explicitly for one of the two.

Under recirculation it still holds that the ratio in your tank shifts over the run even when your EC stays level, so measure more often and refresh in good time.

The high concentration makes it economical and the liquid dissolves quickly, so no crystallisation occurs in the tank and your lines stay open.

Dosing and storage

Shake well before use. Add 2.5 ml of Hydro A per litre of water, 1 to 400, together with the same amount of Hydro B. Give that solution at every watering, in the growth as well as the flowering phase.

Transport upright and store in the dark, at a temperature between 10 and 35 degrees.

Available sizes

Technical Specifications:

• Type: two-part bio-mineral base nutrient for growth and bloom
• Manufacturer: Plagron, 100% HYDRO range
• Component A: NPK 5-0-2, with calcium nitrate, magnesium nitrate and potassium chloride
• Component B: NPK 2-4-9, with 4% P2O5 and 9% K2O
• Chelate form: DTPA, for uptake across a wide pH range
• Dosage: 2.5 ml of A per litre of water, 1 to 400, plus the same amount of B
• Ratio: A and B always in equal parts
• System: suitable for drain-to-waste and for recirculation
• Substrate: all types of inert substrates
• Storage: upright, dark, between 10 and 35 degrees

Frequently asked questions

What is DTPA and why is it on this page?
It is the chelate form the trace elements come in. DTPA keeps them available across a wider pH range, including when your pH drifts or your root zone runs cold.

Can I pour A and B together undiluted?
No. The calcium from A and the phosphate from B then form an insoluble compound that settles in your tank.

Can I use only A or only B?
No, always in equal parts. On their own each bottle misses exactly what the other supplies.

Does it work in a recirculating system?
Yes, this nutrient suits drain-to-waste and recirculation both. Do measure more often under recirculation, because the ratio in your tank shifts while your EC can stay level.

How much per litre?
2.5 ml of A per litre, 1 to 400, and the same amount of B.