Plagron PK 13/14 — Phosphorus & Potassium Booster for Flowering Stage
Best for: Growers wanting proven yield density and flower quality during the critical flowering phase without premium brand pricing
Our thoughts
This is a workhorse PK booster that's been delivering consistent results across European grows for years. Plagron know what they're doing with mineral nutrition, and at this price point you're getting a properly formulated product that rivals the premium brands. One a lot of growers rate highly once they've run a cycle with it.
Plagron PK 13/14 is a concentrated mineral phosphorus and potassium booster designed specifically for the flowering stage. It provides a direct hit of the two macronutrients plants demand most when they're developing flowers and fruit — phosphorus drives flower formation and density, potassium strengthens structure and finish. Used alongside your base nutrient from week four of flowering onwards, it noticeably increases flower site count, tightens flower clusters, and improves overall crop quality. This is a supplement that actually moves the dial.
How it compares
PK boosters sit in a clear market tier. Here's where Plagron lands:
- Directly comparable to Canna PK 13/14 in formulation and results, but significantly cheaper
- Transparent mineral formula with no ballast or unnecessary fillers — you're paying for nutrients, not water weight
- Faster than organic alternatives, with visible plant response within days of first application
- Works in any growing medium or system — hydro, coco, soil — unlike locked-in nutrient lines
The honest comparison: premium brands like Canna and Advanced Nutrients charge a heavy markup for brand recognition. Plagron delivers the same chemistry at better value.
Usage guidance
PK 13/14 is straightforward to use, but timing and dosage matter.
When to start
Begin in week four of the flowering phase. If you're flowering early-stage varieties, watch for flower development visually — that's your cue to start dosing.
Dosage
Add 2ml of PK 13/14 per litre of nutrient solution (that's a 1:500 ratio). Mix it in first, then add your base flowering nutrient until you hit your target EC. This is a concentrate — it's meant to work alongside, not replace, your main feed.
Application frequency
Use it every watering from week four through to the final flush. It integrates cleanly into any feeding schedule — hydro, hand-watering, drip system, doesn't matter.
pH and water quality
Maintain solution pH between 5.5 and 6.5. The product is fully soluble and chlorine-free, so it plays well with most water sources.
Real-world results
Growers consistently report tighter flower clusters, increased flower site density, and improved finish within one to two weeks of starting PK 13/14. It's a visible upgrade, not a subtle one.
Technical specifications
- Nutrient composition: 0-13-14 NPK (13% phosphorus, 14% potassium)
- Phosphorus content: 160 grams per litre (as P₂O₅)
- Potassium content: 170 grams per litre (as K₂O)
- Formulation: Transparent mineral concentrate
- Ballast & chlorine: Free
- Recommended pH range: 5.5 – 6.5
- Dosage: 2ml per litre of water (1:500 ratio)
- Shelf life (unopened): 4 years
- Available sizes: 100ml, 250ml, 500ml, 1L, 5L, 10L, 20L
Who this is for
- Growers running mineral-based nutrient systems (hydro, coco with liquid feeds)
- Anyone mid-cycle looking to noticeably upgrade flower quality and density
- Budget-conscious growers who want premium results without premium pricing
- Existing Plagron users building out a complete feeding programme
- First-time booster users — the results are obvious enough to justify learning the timing
Not suitable for fully organic growing systems, but compatible with every other medium and method. If you're running mineral nutrition, you've got no compatibility concerns.
Our take
Plagron PK 13/14 is proper phosphorus and potassium nutrition at a price that actually makes sense. It's been proven across thousands of grows, the formulation is clean, and the results are measurable. You'll see tighter flowers and more of them — that's what you're paying for, and it delivers.
If you're serious about flowering performance and don't want to overpay for a Dutch label, this is worth picking up while clearance stock lasts. Does exactly what a PK booster should do, week after week.
