The Ideal PK Ratio

If you’re looking for good PK (phosphorous : potassium) additives for hydroponics — especially ones with strong ratios for flowering/fruiting phases — here are some good options and things to watch out for

What to look out for...

• Ratio of P:K — usually bloom boosters are somewhere between 1:1 up to 1:2 or even more K-heavy (depending on the plant & stage).
• Form of nutrients: water-soluble, chelated etc so root uptake is good.
• That the product doesn’t overload EC / salt stress + doesn’t antagonise other nutrients.
• Peak flowering use (last few weeks) often when these are most useful.

Examples...

• Plant Magic PK 13/14~13% P / 14% K (“PK 13/14”) — nearly 1:1 ratio.
• Shogun PK Warrior 9-189 : 18 (P : K) — more potassium heavy.
• Mills Ultimate PK 0-7-67 : 6 (P : K) — slightly more P but balanced.
• Vitalink PK 13-1413 : 14 — high-PK balanced booster.
• Canna PK 13/1413 : 14 — a standard choice.

Product Suggestions...

Here are some PK additives / boosters you could buy that have good P:K ratios.

• Plant Magic PK 13/14 — nearly 1:1, great all-round bloom booster..
• Canna PK 13/14 — established product; widely used.
• VitaLink PK (5 L) — good size; same PK ratio.
• Ionic PK Boost — good multiplier; useful in middle-late bloom.
• The Source Alluvium PK Stimulator (0‑18‑20) — very high P & K; more aggressive, so use carefully.
• Plant Magic Platinum PK 9‑18 — more K heavy, good if you feel your flowering is lagging.
• House & Garden PK 13‑14 — premium; good quality.
• Intense Nutrients PK‑Phite — special form (phosphite) which may have different uptake / effects; can help in certain conditions.

Give us a call or visit and let us know what you are growing and at what stage of growth it is and we will offer you the best suggestions!