Mills Calmag
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Mills Calmag
Mills Calmag – Calcium & Magnesium Supplement
Mills Calmag is a highly concentrated calcium and magnesium supplement designed to prevent and correct nutrient deficiencies while supporting healthy plant growth and flowering. Formulated using calcium nitrate and magnesium oxide, it provides two essential nutrients involved in plant structure, photosynthesis and nutrient uptake.
Particularly beneficial when growing in coco coir or using reverse osmosis (RO) water, Mills Calmag can also be used with hard or soft water. It helps replenish essential minerals and can improve pH stability in low-mineral water.
Key Features
- Highly concentrated calcium and magnesium supplement
- Helps prevent and correct nutrient deficiencies
- Supports healthy foliage, strong growth and flowering
- Particularly useful for coco coir cultivation
- Adds essential minerals to RO and soft water
- Can help improve pH stability in low-mineral water
- Suitable for use throughout vegetative growth and flowering
Why Use Mills Calmag?
Calcium and magnesium play important roles in plant development. Maintaining adequate levels helps prevent deficiencies and supports efficient nutrient use.
| Nutrient | Role in Plant Development |
|---|---|
| Calcium | Supports cell wall development, strong plant structure and healthy new growth. |
| Magnesium | Essential for chlorophyll production, photosynthesis and healthy foliage. |
How to Use Mills Calmag
Add Mills Calmag at a rate of 1ml per litre of water during vegetative growth and flowering, adjusting your overall feeding programme to suit your plants and water quality.
- Fill your reservoir or watering container with water.
- Add Mills Calmag at 1ml per litre and mix thoroughly.
- Add any other required supplements, followed by your base nutrients.
- Check the final EC and pH, adjusting where necessary.
Tip: When using an EC meter, account for the EC contribution from Calmag before adding your base nutrients to avoid overfeeding.
Using Mills Calmag with Coco Coir
Coco coir can retain calcium and magnesium, potentially reducing their availability to plants. Supplementing with Calmag can help prevent deficiencies, which may appear as yellowing leaves or poor new growth.
When preparing untreated coco coir, you can pre-soak the growing medium with a solution of Mills Calmag at 1ml per litre. Water until a little solution drains from the bottom of the pot, then leave overnight before planting.
Product Information
| Product Type | Calcium and magnesium supplement |
|---|---|
| Formulation | Calcium nitrate and magnesium oxide |
| Recommended Dosage | 1ml per litre |
| Growth Stages | Vegetative and flowering |
| Water Compatibility | Hard, soft and RO water |
| Growing Media | Soil, coco and hydroponics |
Mills Feeding Schedule
For guidance on using Mills Calmag alongside Basis A & B and other Mills nutrients, visit our Mills Feeding Schedules page.
Mills Feedchart UK
- Calcium Magnesium Supplement
- Helps prevent and cure deficiencies
- Highly concentrated
- Stabilizes pH
| Weight | 1.1000 kg |
|---|---|
| Size | 1 Litre, 5 Litre |
FREE NEXT DAY DELIVERY – Delivery Information
We offer FREE NEXT-DAY DELIVERY on orders over £75*
*An additional heavy goods surcharge may be applied to heavy or bulky goods (more info).
**Regional delivery surcharges apply for Scotland, Northern Ireland and the rest of the UK.
Orders Under £75
– Orders under £75 and under 5KG will be charged £7.99 (inc vat).
– Orders under £75 and 5KG+ will be charged at £8.99 (inc vat).
Our Next Working Day Delivery Policy
We will always do our utmost to deliver goods to you the next working day for all orders placed before 3pm (Mon-Thurs).



