Plagron - Cocos A&B

Cocos A&B is Plagron's highly concentrated bio-mineral base feed for coco, for growth and bloom. Plagron publish something alongside it that almost no manufacturer writes down: how long your mixed nutrient solution stays good.

Four to ten days, and 48 hours with anything organic in it

Plagron state that you can keep the nutrient solution for between four and ten days, depending on the hygiene of your growing space and your reservoir. That is a wide range, and it is honest: it depends on how clean your tank is, not on the bottle.

Beside it they set a hard limit. Do not use organic products in your nutrient solution, because those can spoil after 48 hours. A mineral solution is a salt solution and has little to spoil; the moment organic material is in it, it is food, and in a warm dark tank with a pump in it food always finds something waiting for it.

That is why growers on a mineral line can leave a tank standing for a week and growers using organic additives cannot. It is not the brand that makes the difference but what you put in.

And there is a third point Plagron add: check your pH daily if you can, because it slowly rises. A tank you set to 5.8 on Friday reads higher by Monday, and the plant notices before you do.

What is in it

Plagron publish both parts in full. Cocos A is water with calcium nitrate, magnesium nitrate and potassium nitrate: an NPK fertiliser at 4-0-1, with 3.9% total nitrogen all of it nitrate nitrogen, 1% water-soluble potassium oxide and 4.5% calcium.

Cocos B is water with magnesium sulfate, magnesium nitrate, monopotassium phosphate and phosphoric acid: an NPK fertiliser at 1-4-2, with 1% total nitrogen also entirely nitrate, 4.1% water-soluble phosphorus pentoxide and 2.4% water-soluble potassium oxide.

Two things stand out. The nitrogen in both bottles is entirely nitrate, so there is no ammonium acidifying your root zone. And the calcium is only in A while the phosphorus is only in B, which are precisely the two elements you do not want together in concentrate.

Plagron also name humic and fulvic acids in this feed, and state that no crystallisation occurs in the reservoir.

Equal parts, and why that is written down

The dose is a maximum of 4 ml of Cocos A per litre of water, meaning 1:250, and with every dose of Cocos A you use an equal amount of Cocos B.

That "equal amount" is not filler. The two bottles are designed together as one analysis: 4-0-1 plus 1-4-2 gives the ratio Plagron intend. Give more A than B and you shift toward nitrogen and calcium; give more B and you shift toward phosphorus. Either way you get something that appears on no label and has no schedule behind it.

The order is the same as with any two-part feed, and Plagron say it explicitly: A and B may only be combined once they have been mixed with water. Do not add them at the same time, but one by one.

In use

At every watering, throughout the growth and flowering phases. Shake well before use.

Plagron add a practical tip specific to coco: water enough that you get 10 to 25% drain daily. On coco that flushes out the salts that would otherwise accumulate, and your drain doubles as your measuring point.

Available sizes

Technical Specifications:

• Type: bio-mineral two-part base feed for coco
• Manufacturer: Plagron
• Cocos A: NPK 4-0-1, 3.9% nitrogen entirely as nitrate, 1% K2O, 4.5% calcium
• Cocos B: NPK 1-4-2, 1% nitrogen entirely as nitrate, 4.1% P2O5, 2.4% K2O
• Dose: a maximum of 4 ml of A per litre of water (1:250), with an equal amount of B
• Order: one by one into the water, not at the same time
• Mixed reservoir keeps: four to ten days, 48 hours with organic products in it
• pH: check daily, it rises slowly
• Drain: 10 to 25% daily
• Also present: humic and fulvic acids

Frequently asked questions

How long does my mixed reservoir keep?
Four to ten days, depending on the hygiene of your space and your tank. With an organic product in it, 48 hours.

Do I need exactly as much A as B?
Yes. The two together form one analysis; an uneven ratio gives you something that appears on no label.

Can I add them to the water at the same time?
No, one by one. Plagron specify it explicitly.

Is there ammonium in it?
No. The nitrogen in both bottles is entirely nitrate nitrogen.

How much drain should I aim for?
Plagron advise 10 to 25% drain daily on coco.