Bloom Yellow Bottles - Cal-Mag

Bloom Yellow Bottles Cal-Mag is a concentrated calcium and magnesium supplement designed to support healthy plant growth, strengthen cell walls and maintain efficient photosynthesis. Part of the Bloom Advanced Floriculture nutrient range, this liquid additive supplies two essential secondary macronutrients alongside chelated iron and zinc, helping growers maintain balanced plant nutrition throughout the growing cycle.

Calcium plays an important role in cell wall development and nutrient transport, while magnesium is a key component of chlorophyll, which plants need for photosynthesis. Bloom Cal-Mag helps maintain an adequate supply of these nutrients during both vegetative growth and flowering, supporting healthy foliage and overall plant development.

Particularly useful for growers using soft water, reverse osmosis water or coco coir, Bloom Yellow Bottles Cal-Mag can help address insufficient calcium and magnesium availability. Its concentrated formula is suitable for hydroponics, coco and soil cultivation, making it a versatile nutrient supplement for indoor grow tents, grow rooms, greenhouses and outdoor gardens.

Key Features

• Concentrated calcium and magnesium supplement designed to support balanced plant nutrition.
• Supplies calcium to support cell wall formation, structural development and nutrient transport.
• Provides magnesium, an essential component of chlorophyll required for photosynthesis.
• Contains calcium nitrate and magnesium nitrate as sources of essential plant nutrients.
• Includes chelated iron and zinc to provide additional micronutrient support.
• Helps prevent or correct plant health problems associated with inadequate calcium and magnesium availability.
• Supports healthy green foliage by maintaining the magnesium supply required for chlorophyll production.
• Particularly beneficial when using soft water or reverse osmosis (RO) water, which may contain low levels of calcium and magnesium.
• Suitable for coco coir growing, where calcium and magnesium supplementation may be necessary depending on the substrate and feeding programme.
• Supports nutrient availability during flowering, including the plant's use of phosphorus and potassium.
• Suitable for application throughout the vegetative and flowering stages.
• Can be used with the Bloom Advanced Floriculture base nutrient range without automatically reducing the recommended base fertiliser application.
• Suitable for recirculating hydroponics, run-to-waste irrigation and soil cultivation.
• Manufacturer-listed general application rate of 1ml per litre of nutrient solution.
• Suitable for indoor and outdoor cultivation, including hydroponic grow tents, grow rooms and greenhouses.
• Available in 300ml, 1L, 2.5L, 15L and 25L sizes.
• Manufactured in Australia as part of the Bloom Yellow Bottles nutrient range.

Specifications

Who It’s For

Bloom Yellow Bottles Cal-Mag is ideal for growers looking to maintain an adequate supply of calcium and magnesium throughout the plant growth cycle. It is particularly useful for hydroponic growers using soft or reverse osmosis water, where the natural mineral content may be insufficient to meet plant requirements.

Growers cultivating in coco coir can also benefit from a dedicated Cal-Mag supplement, as calcium and magnesium availability can be influenced by the properties of the growing medium. Soil gardeners may use Bloom Cal-Mag where their existing nutrient programme or growing conditions do not provide adequate levels of these essential minerals.

The product is suitable for hobby growers and commercial cultivators operating indoor grow tents, grow rooms, greenhouses and outdoor gardens. It is especially relevant to growers following the Bloom Advanced Floriculture feeding programme who want additional secondary macronutrient support during vegetative growth and flowering.

How To Use

Application Timing: Use Bloom Yellow Bottles Cal-Mag throughout the vegetative and flowering stages as part of your regular feeding programme. The manufacturer's UK guidance recommends stopping application when the final flush begins, typically during the last 1–2 weeks before harvest.

Dosage: The manufacturer lists a general application rate of 1ml per litre of nutrient solution. Application rates can vary according to the growing system, water quality and feeding method, so consult the appropriate Bloom Yellow Bottles feeding schedule for your setup.

Mixing: Measure the required quantity of Cal-Mag for your water volume and add it to the nutrient reservoir or watering container. Mix thoroughly before completing your normal nutrient preparation. Follow the manufacturer's feeding schedule and avoid mixing concentrated nutrient products directly together.

Feeding: Apply the prepared solution through your usual hydroponic irrigation system or soil watering method. Bloom Cal-Mag is a supplementary nutrient product and should be used alongside a suitable base fertiliser rather than as a complete plant feed.

Soft Water and RO Water: When using soft water or reverse osmosis water, assess the calcium and magnesium contribution from your existing nutrients before deciding how much additional supplementation is required. Follow the appropriate feeding schedule and monitor the final EC and pH of the prepared solution.

Monitoring Plant Health: Observe foliage and new growth for signs of nutrient imbalance. Yellowing, spotting and abnormal leaf development can have several causes, so check water quality, nutrient strength and root-zone conditions before increasing the Cal-Mag dosage.

Final Flush: Discontinue Bloom Cal-Mag when beginning the final flush, following the manufacturer's feeding guidance for your crop and growing method.

Storage and Handling: Keep the container securely closed and follow the storage and safety instructions printed on the product label. Always measure accurately and use the recommended application rate for your growing system.

All orders are packed in plain discreet parcels with non descript labels for your personal security.

We offer the following shipping options to the mainland UK. If you live outside mainland UK please call us on +44 (0)1142 280024.

Royal Mail delivery options (mainland UK)

Royal mail tracked  £4.75 (up to 2KG only) 2-4 working days

Royal mail tracked  £3.75 (up to 2KG only) 3-5 working days

Courier  Delivery service options (mainland) Zone A Zone A+ Zone B Zone B+

Free delivery up to 25 kilos (over £99) 1-2 working days service 
Next working day  £6.75 up to 25KG 
Next working day am £9.95 over 25KG

Courier Delivery service options Zone C Zone C+ Zone D Zone D+

Next working day  £29.95 + 75P per kg over 25KG
Next working day am £35 + 75P per KG over 25KG

All packages are shipped in plain, discrete packaging. Absolutely NO information is passed to third parties.

Please note that paid for next day delivery only applies if you order before 1PM Monday to Thursday.

Our UK delivery zones: In the UK we have 4 zones. Prices and parcel delivery times vary by zone.


Tracking your consignments

Our deliveries are handled by Parcelforce or DX or Fedex depending on the weight and location.You are able to track your parcels by using your consignment number or customer reference and postcode. If using a reference number to search, please also insert the delivery postcode. You will receive an email on the day for dispatch confirming your order and tracking number, You have the option to select a delivery window or change the day of delivery by clicking the link below and manage my delivery option.


Other Services Available

Isle of Wight & isles of Scilly £5.99 extra per consignment

Timed booked delivery £15.99 extra per consignment

Long bulky items £29.99 extra per consignment (1.4m x 0.8m 0r two persons needs to carry )

We Won't Be Beaten On Price

At Hytec Horticulture we are committed to offering the best range of hydroponic products at the best possible prices. This is why we have our Price Match Promise, whereby if you find an identical product at one of our competitors for a lower price, we will match or even beat it.

In an ever-increasingly competitive marketplace, many product lines are being sold at varying prices. We want to give you the best deal so if you find any of the products we sell (or comparable products) at cheaper prices, give us a chance to get your business, save you money, and beat that price. 

Terms & Conditions

To qualify for the Price Match Promise, the product must conform to the following:

• The product in question must be identical (it should be the same brand & model and for sale with the same terms & conditions)
• The product must be held in stock by the competitor at the time you want to make the price match
• In addition to the above, we must also have the product in stock
• We must be able to verify the lower price either by the store's website, a phone call or a written quote on headed paper
• The product is not part of a promotion, sale or clearance offer
• The product must be available from a physical store that’s open to the public
• Our Price Match Promise is not available against web-only retailers, for example, eBay or Amazon, along with factory outlets, private or liquidation sales
• Typographical errors, incorrect pricing, voucher codes or additional discounts by the competitor, including their own price match offers, are excluded 

Large & Multiple Product Orders

If you want to place a large order with multiple products (for example, you're setting up a grow room from scratch and require a full setup including tent, lights, extraction, nutrients, grow media etc) then get in touch and we will aim to match, or even beat any quotes you’ve been given.