Mills Ultimate PK booster
Updated 18 Oct 2026
Push your plants to the limit. Give your plants the extra horsepower they need at the end of their flowering cycle with Mills Ultimate PK.
Usage & Instructions
Use 2 ml per litre from week 5 of flowering, increasing to 2.5 ml per litre from week 7. Follow the Mills Regular growth chart.
Product Specifications
Description
Mills Ultimate PK booster is a late-flowering phosphorus and potassium booster enriched with chelated micronutrients. It gives plants extra power at the end of flowering for denser, heavier and healthier fruits while keeping them vital. Part of the Mills Regular (Red Line) programme. NPK 0-7-6 (distributor).
Available variants
Nutrients Regular
All products in the Nutrients Regular range.
Mills Basis A
Mills Basis A is part A of the two-part Mills Basis A & B mineral base nutrient. Used together in equal amounts, A and B supply all macro- and micronutrients in balanced proportions for both the vegetative and flowering phases. NPK 3-0-1.
Mills Basis B
Mills Basis B is part B of the two-part Mills Basis A & B mineral base nutrient. Used together in equal amounts, A and B supply all macro- and micronutrients in balanced proportions for both the vegetative and flowering phases. NPK 0-4-3.
Mills C4
Mills C4 is a liquid bloom stimulator that encourages early flower sets and assists carbohydrate delivery and the production of essential oils. It is a concentrated mix of sugars, vitamins, amino acids and humic acids. NPK 0.7-3-3.
Mills Start-R
Mills Start-R is an organic-mineral root stimulator for seedlings, vegetative plants and early bloom. It promotes a healthy root system, reduces transplant shock and combines organic and mineral components in one bottle. NPK 5-0-0.5.
More from Mills
Other products by Mills.
Mills CalMag
Mills CalMag is a highly concentrated liquid calcium and magnesium supplement. It corrects and prevents Ca and Mg deficiencies, supports growth and vitality and stabilises EC, and is essential with soft water or reverse-osmosis water.
Mills Coco & Cork
Mills Coco & Cork is a ready-to-use blend of 75% RHP-certified coco peat and 25% fine cork. The cork provides superior aeration for root development, so no perlite is needed and no mixing or buffering is required. For indoor and outdoor use.
Mills Cocopeat
Mills Cocopeat is a pH-neutral coco substrate of coco fibres and coco gravel with a light consistency that balances moisture and aeration, encouraging strong and extensive root systems. Supplied in 50 L bags.
Mills Light Mix
Mills Light Mix is a peat-based growing mix with sphagnum and perlite for commercial applications, moderately pre-fertilised with NPK 14-16-18 fertiliser. It uses carefully selected and filtered mosses and has an EC of 1.2-1.4.
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