Plagron - PK 13-14

A mineral PK fertiliser, EC fertiliser 0-13-14, with 13% water-soluble P2O5 and 14% water-soluble K2O. Maximum 2 ml per litre, at every watering throughout flowering.

Two schools, and they do not contradict each other

Set the directions from the PK bottles on this shelf side by side and you find a difference of a factor of six. Plagron say: every watering, right through flowering. CANNA say: one week maximum. Other brands say the peak weeks, roughly four to six.

That looks like disagreement about the chemistry and is not. Phosphorus and potassium do the same thing whatever the brand. What differs is the strategy for getting them into the plant: a low dose held for a long time, or a high dose in a short burst.

Both work, and they suit different ways of growing. A low dose across the whole of flowering gives a flatter, more predictable line and suits anyone tracking EC closely. A short burst at the right moment asks you to pick that moment well, but keeps your phosphate and potassium load low in the weeks before it.

What does not work is taking the duration from one brand and the dose from another. Feed a week-product's dose for the whole of flowering and you build a salt accumulation no manufacturer put their name to.

If your reservoir goes cloudy

Plagron give an instruction you rarely see on a bottle and that can save you a tank: if the nutrient solution turns cloudy, bring the pH below 6.0 and repeat the mixing procedure.

Cloudiness means something is precipitating, and with a PK that is almost always phosphate bonding to calcium. The higher the pH, the more readily it happens. Dropping below 6.0 brings those compounds back into solution, and mixing again distributes them.

The order that prevents it: PK into the water first, then your base nutrients up to the EC you want, and adjust pH last.

Dosing

Mix a maximum of 2 ml per litre of water, a ratio of 1 in 500. Then add your base nutrients until you reach the EC you want. For use at every watering throughout the flowering phase.

Note that this is the highest per-litre dose of any PK in this range. That is consistent with a product fed lightly and continuously, but it also means a bottle empties faster than its size suggests.

Available sizes

Technical Specifications:

• Type: mineral PK fertiliser, EC fertiliser
• Manufacturer: Plagron
• Registration: 0-13-14
• Phosphorus pentoxide (P2O5): 13%, water soluble
• Potassium oxide (K2O): 14%, water soluble
• Dose: maximum 2 ml per litre of water (1 in 500)
• Order: PK first, then base nutrients up to the EC you want
• Period: every watering throughout the flowering phase
• If it goes cloudy: bring the pH below 6.0 and repeat the mixing procedure

Frequently asked questions

Whole bloom or one week?
Plagron specify the whole flowering phase at a low dose. Other brands work with a short burst at a high dose. Keep the duration and the dose from the same brand; do not mix them.

My nutrient solution has gone cloudy.
Bring the pH below 6.0 and mix again. Cloudiness with a PK is usually phosphate that has precipitated with calcium.

In what order do I mix?
PK into the water first, then base nutrients to the EC you want, and pH last.

Why is the dose higher here than with other brands?
Because it is meant as a light, continuous feed rather than a short burst. Compare per litre of feed water, not per bottle.

Is this an organic product?
No. Plagron register it as a mineral PK fertiliser, EC fertiliser 0-13-14.