Plagron - Cocos Brix 6 pieces

Six compressed blocks of coco substrate in one pack. You swell each block with water into loose, airy coco. Buffered with calcium, rinsed, and RHP certified.

The buffering is what you are paying for

Untreated coco is not simply a neutral medium. The fibre is naturally loaded with sodium and potassium, and the material readily swaps those ions for calcium and magnesium. Feed fresh, unbuffered coco and the substrate takes part of your calcium and magnesium before the plant can reach it. You then see deficiency symptoms while your meter says you are feeding enough.

Buffering is the process that settles this in advance: the coco is treated with calcium and then rinsed clean, so those exchange sites are already occupied by the time you start. Cocos Brix is supplied that way. That is why you can simply run your schedule from the first watering instead of compensating for a week.

The RHP mark says something else, and the two are worth keeping apart. RHP is about origin and purity: free of sand, weed seed and pathogens, and consistent between batches. Buffering is about chemistry. You want both, and neither guarantees the other.

What it gives you in practice

Coco holds far more water than clay pebbles or stone wool, so you water less often and you have more slack when something gets in the way. Against that, you do have to keep steering each watering on pH, because the medium buffers your solution only to a limited extent.

It need not be thrown away afterwards. Spent coco makes a perfectly good soil improver outdoors.

Technical Specifications:

• Type: compressed coco substrate, buffered
• Composition: buffered coco pith and buffered coco fibre
• Contents: 6 compressed blocks per pack
• Yield per block: Plagron give roughly 7 litres of ready substrate from 4 litres of water
• pH: 5,8 to 6,8 (1:1,5)
• EC: below 0,2 mS/cm (1:1,5)
• Certification: RHP
• Nutrition: contains no fertiliser itself, so add coco feed from the first watering at pH 5,5

Frequently asked questions

How much water goes into one block?
Follow the instruction on your own pack. Plagron currently give 4 litres of water for about 7 litres of substrate. You will also find 6 litres for 9 litres online, an older figure still widely repeated. Too little water is the worse mistake of the two, because the core stays hard.

Do I still need to buffer or pre-rinse?
No. This coco has already been treated with calcium and rinsed. Swelling it with clean water is enough.

Can I use ordinary plant food?
Better not. Choose a feed formulated for coco, because it accounts for the calcium and magnesium demand of this medium.

Can I reuse it?
For a second crop it is marginal, since the buffer is largely spent by then. As a soil improver in the garden it is excellent.