Two-part hydroponic fertiliser kit, soft or hard water
This kit contains a two-part mineral fertiliser — a growth part NPK 5-0-5 and a flowering part NPK 1-6-4 — plus a nitrogen-free late-flowering fertiliser NPK 0-6-5, each in a 500 ml bottle. It is available in a soft-water version and a hard-water version, depending on the calcium content of your tap water.
It can be used in hydroponics, on clay pebbles, and in soil.
The summary
- What you receive: a grow part, a bloom part, and an end-of-flowering fertiliser, each in a 500 ml bottle.
- The version: soft water for calcium levels below 70 mg per litre, hard water for levels above.
- The programme: both parts used together throughout the entire cycle, then the nitrogen-free fertiliser for the final 10 days.
- Safety: the grow part should be handled wearing protective goggles.
Three 500 ml mineral fertilisers for a complete cycle, suited to your water hardness
This kit covers a soilless grow from first root to harvest with three 500 ml bottles. The first two form a two-part fertiliser: the growth part supplies nitrogen, potassium, and calcium; the bloom part supplies phosphorus, magnesium, and sulphur. You add both together at each preparation, varying the ratio according to growth stage; then the third bottle, nitrogen-free, takes the plant through to maturation. This is a programme that lets you fine-tune the balance of your solution more precisely than a single-bottle fertiliser.
Choosing the version to suit your water's calcium level
Your local water quality report will show the calcium content, or the hardness in French degrees. Below 70 mg of calcium per litre, roughly 17.5 °f of calcium hardness, choose the soft-water version, whose grow 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 do not have a report to hand, the GH total hardness drop test gives you a clear answer in a few minutes: a colour change reached in 9 drops or fewer on 5 ml confirms less than 70 mg of calcium per litre.
🔀 Two parts whose ratio changes
At the first roots, you add 0.5 ml of each part per litre, then 1.5 ml of the growth part and 1 ml of the flowering part at the first true leaves. During full vegetative growth, the growth part rises to 3 ml per litre against 1 ml of the flowering part, then the two converge at pre-flowering, at 3 ml and 2.5 ml respectively. At flowering, the ratio reverses, with 1.5 ml of the growth part to 3 ml of the flowering part 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 rooting, 1.3 to 1.8 mS during growth, and 1.4 to 2.2 mS during flowering. Measure it after adding both parts one at a time into the reservoir water, never mix them neat together, 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 late-flowering fertiliser, used alone at 5 ml per litre. Deprived of nitrogen, the plant draws on the reserves in its older leaves, which yellow progressively, and completes the ripening of its fruits. In soil, allow 15 days at 4 ml per litre, as the residual nitrogen in the growing medium is depleted more slowly.
🌶️ Three chilli plants in a flood-and-drain table
Take three chilli plants on a small flood-and-drain table with a 25-litre nutrient reservoir. During full growth, you add 75 ml of the grow part, mix, then add 25 ml of the bloom part. During flowering, the mix becomes 37.5 ml of grow and 75 ml of bloom, and for the final 10 days, 125 ml of the late-flowering fertiliser alone. pH is then checked using the liquid drop test.
📊 Runtime of a 25-litre reservoir
At 3 ml per litre, the maximum dose for each part, the grow part and the bloom part each make up approximately 165 litres of solution, and the late-flowering fertiliser yields 100 litres at 5 ml per litre. With a 25-litre reservoir changed weekly, you therefore have 6 to 7 weeks at full dose from each part, and often more, since doses are lower in the early stages. Each fertiliser is also available separately, from a 500 ml bottle up to a 10 L container, such as the grow part in soft water or hard water.
🧴 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, NPK 5-0-5Soft water or hard water version
- Flowering part
- 500 ml, NPK 1-6-4
- Late flowering
- 500 ml, NPK 0-6-5Nitrogen-free
- Total capacity
- 1.5 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 kit
- Weight
- 2.1 kg
- 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, 500 ml, available in soft water or hard water formulation
- 1 part flowering, 500 ml
- 1 late-bloom fertiliser, 500 ml
Contents and weights recorded on 02/10/2026 from the 2026 price list and the manufacturer's data sheet. Doses taken from the 2025 application chart; hazard classifications recorded from the safety data sheets dated 26/07/2024. The threshold of 70 mg of calcium per litre is that specified by the manufacturer.
Which starter kit should you choose?
The five 500 ml fertiliser kits from the shop, compared by grow medium, water type and growing method.
| Starter Kit TriPart: 3 x 500 mlYour choice | Recommended Two-part hydroponic fertiliser kit, soft or hard waterYour choice | Hydroponics starter fertiliser kit, 3 x 500 mlYour choice | Fertiliser kit for hydroponics on 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 | ¥3,700 | ¥4,000 | ¥4,900 | ¥4,000 | ¥4,700 |
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.
Estimate your
delivery time
Your estimate
It covers preparing your order and then the transit time quoted by the carrier, counted in working days.
It is not a guaranteed delivery date: public holidays, peak periods, customs or a carrier delay can extend it. The exact amount, in your currency, is worked out in the cart once your address is entered.
Set dispatched by tracked parcel from France. Exact shipping costs and final delivery times are displayed at checkout once your address has been entered. Outside the European Union, import duties and taxes are the responsibility of the recipient.
Frequently asked questions
8 questions
6 key questions, 8 in the detailed view
You may also like
Let us talk about your project
A question about this product or your setup? Our team will answer and advise you.
Interest-free instalment payments
Offered depending on the cart amount, at checkout.
Delivery in 2 to 15 working days
Depending on the products and shipping sites. Estimate by destination in the estimator on this page.
After-sales service 7 days a week by email or chat
Our team answers all your questions.
Shop responsibly
Become part of the change.







