Two-part hydroponic fertiliser kit, soft or hard water
Regular price
$26.00
Regular price
$32.00
Sale price
$26.00
Unit price
/
per
$8.66 × 3 with no fees
Klarna.
A two-part mineral fertiliser — grow NPK 5-0-5 and bloom NPK 1-6-4 — for hydroponics, clay pebbles, or soil, available in a soft-water or hard-water version depending on your tap water calcium level. The 500 ml kit adds a nitrogen-free late-bloom fertiliser, while the 1 L and 5 L packs bring both parts together for larger reservoirs.
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The summary
- What you receive: grow part, bloom part and end-of-bloom fertiliser in 500 ml in the kit, or both parts in 1 L or 5 L containers in the bundles.
- The version: soft water below 70 mg of calcium per litre, hard water above.
- The programme: both parts together throughout the cycle, then the nitrogen-free fertiliser for the last 10 days.
- Safety: the grow part should be handled with eye protection.
Two-part fertiliser for soft or hard water, in a 500 ml kit or in 1 L and 5 L packs
This kit covers a full soilless grow from the first roots through to harvest using three 500 ml bottles. The first two make up a two-part fertiliser: the grow part supplies nitrogen, potassium, and calcium, while the bloom part supplies phosphorus, magnesium, and sulphur. You add both together at each preparation, adjusting their ratio according to the growth stage; the third bottle, which contains no nitrogen, then guides the ripening phase. This programme gives you far finer control over the nutrient solution balance than a single-bottle fertiliser.
Choosing the version to suit your water's calcium level
Your local water quality report shows the calcium content, or hardness in French degrees. Below 70 mg of calcium per litre, roughly 17.5 °f of calcium hardness, choose the soft water version, whose growth part contains 3.4% calcium oxide. Above that, the hard water version contains only 1%, since your tap water already supplies the rest. This avoids an excess of calcium that would interfere with magnesium uptake. If you don't have a report to hand, the GH total hardness drop test gives you an answer in a few minutes: if the colour change occurs in 9 drops or fewer on 5 ml, your water contains less than 70 mg of calcium per litre.
🔀 Two parts whose ratio changes
At the first roots, apply 0.5 ml of each part per litre, then 1.5 ml of the grow formula and 1 ml of the bloom formula once the first true leaves appear. During full growth, the grow part increases to 3 ml per litre against 1 ml of bloom; the two converge at pre-flowering, with 3 ml and 2.5 ml respectively. In full bloom, the ratio reverses: 1.5 ml of grow to 3 ml of bloom per litre.
Growth part, 500 ml
NPK 5-0-5 with calcium, from 0.5 to 3 ml per litre.
Bloom part, 500 ml
NPK 1-6-4 with magnesium and sulphur, 0.5 to 3 ml per litre.
Late bloom, 500 ml
NPK 0-6-5 nitrogen-free, 5 ml per litre, used on its own.
The conductivity of the solution follows this progression: 0.3 to 0.6 mS at first roots, 1.3 to 1.8 mS during growth, and 1.4 to 2.2 mS during flowering. Measure it after adding both parts one after the other into the reservoir water, never mix them neat, as the calcium in the first part would precipitate with the sulphates in the second. Adjust pH last, keeping it between 5.5 and 6.5 up to full growth, then between 6.4 and 6.8 from pre-flowering through to the end of flowering.
Protecting your eyes during preparation
The growth part is classified as hazardous in both its versions, as its concentrate causes serious eye damage. Wear safety goggles when pouring it, rinse thoroughly with water if splashed, and store the kit closed, upright and out of reach of children. The flowering part and the end-of-flowering fertiliser are not classified as hazardous.
During the final 10 days in hydroponics, both parts give way to the end-of-flowering fertiliser, used on its own at 5 ml per litre. Deprived of nitrogen, the plant draws on what is stored in its older leaves, which gradually yellow, and completes the ripening of its fruit. In soil, which retains the solution more than a hydroponic grow medium, the phase extends to 15 days, at 4 ml per litre.
🌶️ Example on a flood-and-drain table
Take three chilli plants on a small ebb-and-flow table with a 25-litre nutrient reservoir. During active growth, pour in 75 ml of the grow part, mix, then add 25 ml of the bloom part. At the flowering stage, the mix becomes 37.5 ml of grow and 75 ml of bloom, and during the final 10 days, 125 ml of the end-of-bloom fertiliser alone. Measure the pH afterwards using the drop test.
📊 Runtime of a 25-litre reservoir
At 3 ml per litre, the highest dose of each, the grow part and the bloom part each prepare around 165 litres of solution, and the late-flowering fertiliser 100 litres at 5 ml per litre. For a 25-litre reservoir refreshed weekly, you therefore have 6 to 7 weeks at full dose for each part, and often more, since doses remain lower in the early stages. Each fertiliser is also available individually, from a 500 ml bottle to a 10 L container, such as the grow part in soft water or hard water.
📦 Large-format bundles
Once you are happy with the programme, the 2 x 1 L and 2 x 5 L packs bring together the grow part, in whichever soft-water or hard-water version you have chosen, and the bloom part in the same format. At 3 ml per litre, a 1 L bottle prepares approximately 333 litres of solution, which equates to 13 weeks for a 25-litre reservoir in the example, topped up each week at full dose. A 5 L bottle covers approximately 1,650 litres and suits a setup of several hundred litres. The late-bloom fertiliser is then ordered in the format that matches your reservoir, and each pack costs less than its two bottles purchased separately.
🧴 Storing the three bottles
Once opened, all three fertilisers keep for 5 years, stored upright with lids screwed on, away from sunlight and frost, and should be shaken before each use. The kit, which weighs 2.1 kg, brings together the complete programme at a lower price than buying the three bottles individually, making it an ideal way to try the two-part programme before moving up to larger formats.
Technical specifications
The contents
- Growth stage
- 500 ml, 1 L or 5 L, NPK 5-0-5Soft water or hard water version
- Flowering part
- 500 ml, 1 L or 5 L, NPK 1-6-4
- Late flowering
- 500 ml, NPK 0-6-5Nitrogen-free, in the 500 ml kit
- Total capacity
- 1.5 L, 2 L or 10 L
Use
- Maximum dose per part
- 5 ml/L
- Late flowering
- 5 ml/L4 ml/L in soil
- Hard water version
- Above 70 mg/L of calcium
- Solution pH
- 5.5 to 6.5, then 6.4 to 6.8 during flowering
The parcel
- Weight
- 2,1, 2,5 or 12,1 kgKit, 1 L pack, 5 L pack
- Standard
- Regulation (EU) 2019/1009
- Hazard classification
- DangerGrowth part: H318
- Organic farming
- Not suitable
To budget for separately
- pH measurement
- A pH test kit in drops
- Rinsing the grow medium
- A flushing solution
6 further specifications are available in the detailed view.
In the box
- 1 growth part, in soft water or hard water version
- 1 bloom part
- 1 end-of-flowering fertiliser, 500 ml, included in the kit
- Bottles of 500 ml, containers of 1 L or 5 L, depending on the format chosen
Contents and weights recorded on 02/10/2026 from the 2026 price list and the manufacturer's product sheet. Doses taken from the 2025 application table; hazard classifications recorded from the safety data sheets dated 26/07/2024. The 70 mg calcium per litre threshold and end-of-flowering durations were recorded on 07/10/2026 from the manufacturer's shop. Batch contents recorded on 07/10/2026.
Which starter kit should you choose?
The five 500 ml fertiliser kits from the shop, compared by grow medium, water type and growing method.
Five kits to start a grow
They all cover a complete cycle, but they are not aimed at the same grow medium or the same water.
| Three-part hydroponics fertiliser kit, for soft or hard waterYour choice | Recommended Two-part hydroponic fertiliser kit, soft or hard waterYour choice | Hydroponics starter fertiliser kit, 3 x 500 mlYour choice | Fertiliser kit for coco fibre, from growth to harvestYour choice | Organic fertiliser kit for getting started, growth and floweringYour choice | |
|---|---|---|---|---|---|
| Bottles poured together during full growth | 3 | 2 | 1 | 2 | 1 |
| Solution prepared by the growth bottle (L) | 278 L | 167 L | 333 L | 200 L | 250 L |
| Hard water version | Yes | Yes | No | No | No |
| Calcium-enriched for coco fibre | No | No | No | Yes | No |
| End-of-cycle fertiliser with no nitrogen included | No | Yes | Yes | Yes | No |
| Suitable for organic farming | No | No | No | No | Yes |
| At least one bottle classified as hazardous | Yes | Yes | Yes | Yes | No |
| Price | $23.00 | $26.00 | $31.00 | $26.00 | $30.00 |
Three-part hydroponics fertiliser kit, for soft or hard water
Bottles poured together during full growth3
Solution prepared by the growth bottle (L)278 L
Hard water versionYes
Calcium-enriched for coco fibreNo
End-of-cycle fertiliser with no nitrogen includedNo
Suitable for organic farmingNo
At least one bottle classified as hazardousYes
Two-part hydroponic fertiliser kit, soft or hard waterRecommended
Bottles poured together during full growth2
Solution prepared by the growth bottle (L)167 L
Hard water versionYes
Calcium-enriched for coco fibreNo
End-of-cycle fertiliser with no nitrogen includedYes
Suitable for organic farmingNo
At least one bottle classified as hazardousYes
Hydroponics starter fertiliser kit, 3 x 500 ml
Bottles poured together during full growth1
Solution prepared by the growth bottle (L)333 L
Hard water versionNo
Calcium-enriched for coco fibreNo
End-of-cycle fertiliser with no nitrogen includedYes
Suitable for organic farmingNo
At least one bottle classified as hazardousYes
Fertiliser kit for coco fibre, from growth to harvest
Bottles poured together during full growth2
Solution prepared by the growth bottle (L)200 L
Hard water versionNo
Calcium-enriched for coco fibreYes
End-of-cycle fertiliser with no nitrogen includedYes
Suitable for organic farmingNo
At least one bottle classified as hazardousYes
Organic fertiliser kit for getting started, growth and flowering
Bottles poured together during full growth1
Solution prepared by the growth bottle (L)250 L
Hard water versionNo
Calcium-enriched for coco fibreNo
End-of-cycle fertiliser with no nitrogen includedNo
Suitable for organic farmingYes
At least one bottle classified as hazardousNo
Application rates from the 2025 dosage chart, contents from the official product kit pages and safety data sheet classifications, recorded on 07/10/2026.
Help choosing
Which kit to get started at home?
Documents & manuals
Safety data sheet, freshwater growth
The data sheet details the composition and hazard statements of the growth part for soft water.
Safety data sheet, hard water grow
The data sheet details the composition and hazard statements of the growth part for hard water.
Safety data sheet, flowering stage
The data sheet covers the composition, storage and first-aid instructions for the flowering part.
Safety data sheet for the late-bloom fertiliser
The product sheet details the composition and storage of the nitrogen-free fertiliser.
Document not showing? Some publishers block display inside a frame, so open it in a tab.
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Frequently asked questions
8 questions
6 key questions, 8 in the detailed view
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