The best hydroponic fertilisers, compared.
Top pick: BioBizz Fish-Mix, 1 litre Best value: Growth Technology Formulex, 1 litre – Lowest shelf price at the next score, about £11.77, 4.6 from 140 reviews, with a 1:99 ratio field. Updated October 2026.
Hydroponic fertiliser is a plant food you dissolve in water because the roots are not in garden soil. In the UK you buy it for a small kit, for LECA or a jar, for coco coir, or for a tank that returns the same solution to the roots. The shelf mixes one-part solutions, two-part A and B nutrients, and organic emulsions that also name hydroponics. The Royal Horticultural Society defines the method as mineral salts in water, with a usual pH of 5.8 to 6.2, a conductivity check as plants drink, and a fresh mix about every two weeks. A suitable bottle names the system: soil, coco, recirculating, or all-purpose. It gives an English dose in millilitres per litre, and it is a base nutrient for that stage rather than only a booster. Seedling formulas are gentler. A flowering A and B is not a whole-life feed. A high-nitrogen emulsion is a vegetative tool. A unit count of 1 ml against a much larger title means you cannot follow the dose. See the [hydroponic fertiliser buying guide](/hub/fertiliser-soil-and-bark-mulch/hydroponic-fertiliser/sub/hydroponic-fertiliser-buying-guide).
Hydroponic fertiliser is a plant food you dissolve in water because the roots are not in garden soil.
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Personal buying guide
Question 1 of 2
Which system do you need the label to name?
BioBizz Fish-Mix is listed at £12.56 with a 1 litre title, and the star line is 4.7 from 2,059 reviews, the largest count in this set, which scales to the same 94 as CANNA Coco. The first 50 United Kingdom texts are in the stored notes. The item highlight names soil, coco, and hydroponics and calls it a nitrogen-rich feed for vegetative growth. Smell is the complaint that recurs: a mix used immediately is described as milder, and a mix left for a day or more is described as very strong, including indoors overnight. The mixing-ratio field is 1:0, which is not a usable rate, and dilutions quoted in reviews are habits rather than a label chart. Title, unit count, and liquid volume say 1 litre, while the item weight is 227 g, so the pack size does not agree. Country of origin is given as España. The review file is the deepest here, and the weight clash plus the soil-first bullets are why it does not take the top-pick badge.
Pros
Cons
Best for: Soil or coco in vegetative growth, when you will mix only what you use straight away.
Less suitable: A small flat, a recirculating tank, or anyone who needs a mineral A and B chart.
Specifications
Common questions
What systems does the listing name?
The item highlight says soil, coco, and hydroponics, and calls it a nitrogen-rich feed for vegetative growth. The bullets stress outdoor herbs and vegetables, soil conditioning, and a strong foliar dilution.
What do the UK reviews say about the smell?
Smell is the main complaint in the first 50 texts. Used immediately, some reviewers call it mild. A mix left for a day or more is described as very strong, including one indoor overnight complaint. Reviewers say to mix only what you will use straight away.
What dose is on the Amazon fields?
The mixing-ratio field is 1:0, which is not a usable rate. Reviewers quote their own dilutions. The stored notes do not include a maker chart.
CANNA Coco A and B is the 1 litre set at £17.56, and it is the top pick here because the star line is 4.7 from 1,969 reviews on a listing that is a coco nutrient, tied at 94 with Fish-Mix. The stored notes hold the first 50 United Kingdom texts. Those texts point you to a feed chart, and one reviewer measured 5 ml of each part per litre and wanted separate pipettes. The Amazon mixing-ratio field says 1:1 on that two-bottle set, which only says the parts are equal and is not a millilitres chart. The stored notes do not print one. Two of those 50 texts say the instructions on the B bottle are in French. Title and liquid volume say 1 litre, the weight is 998 g, the unit count is 1.0 count, and number of items is 1, so the pack reads as a set rather than one agreed litre. One stored text blames a leak partly on delivery, and another describes a lost parcel that was replaced.
Pros
Cons
Best for: You grow in coir and will follow CANNA's own chart rather than the 1:1 field.
Less suitable: A recirculating tank in flower, or a flat that wants a single one-part bottle.
Specifications
Common questions
Is this one bottle or two?
The title is a Canna Coco 1 litre A and B bottle set. Number of items is 1 and the unit count is 1.0 count. The liquid-volume field says 1 litre and the weight is 998 g.
What mix ratio is on the Amazon listing?
The mixing-ratio field is 1:1. Reviews in the stored notes say to follow the feed chart. One reviewer measured 5 ml of each part per litre and wanted separate pipettes. The listing does not print a full chart.
Are the bottle instructions in English?
Two of the first 50 UK reviews say the instructions on the B bottle are in French. One of those reviewers already knew the product. The other said a first-time user could have trouble.
Growth Technology Formulex, 1 litre, is a one-part mineral solution at £11.77, and the mixing-ratio field on amazon.co.uk is 1:99. The listing line is 4.6 from 140 reviews, with 21 United Kingdom texts in the stored notes. The bullets name seedlings, transplants, clones, foliar feeding, and Rockwool pre-treatment, and they say the pH is buffered so you usually do not adjust it once the feed is in solution. They do not give a target pH number. Unit count and liquid volume both say 1 litre and the weight is 1 kg, while the number-of-items field says 1000 against that one bottle, so the litre fields agree with each other and the item count does not. Notes on those stored texts include use on LECA, monstera, and chilli seedlings, and one buyer called the litre a little expensive. It is the best value in this set because it is the lower ticket at the 4.6 score and the dose string is readable, and that is still not a feeding trial.
Pros
Cons
Best for: You want one mineral bottle for seedlings, a small kit, or a foliar mix, and you will follow the 1:99 field rather than another brand's chart.
Less suitable: You need coco A and B, a recirculating bloom set, or a listing whose item count matches one bottle.
Specifications
Common questions
Is this a liquid, and what size is the bottle?
The listing form is liquid. The title, unit count, and liquid volume all say 1 litre, and the weight is 1 kg. The number-of-items field says 1000, which does not match one bottle.
Does the listing say you must adjust the pH?
The bullets say Formulex has a buffered pH and usually needs no pH adjustment once it is in solution. They do not give a target pH number.
What dose is printed on the Amazon fields?
The mixing-ratio field is 1:99. The stored notes do not print a millilitres-per-litre chart.
The 5 litre Formulex bottle is the same one-part mineral listing as the 1 litre, priced at £29.89, which is about £5.98 a litre if you use the whole bottle. The amazon.co.uk line is 4.6 from 41 reviews, and six United Kingdom texts are in the stored notes. Title, unit count (5000 ml), liquid volume, and number of items (1) agree on the volume, and the country of origin is the United Kingdom. The mixing-ratio field is not a usable figure, so this listing does not give you millilitres per litre. One of the six texts says it works but the opening could pour better. Item weight is not filled in. Take the 5 litres when you already know you will finish Formulex, and keep the 1 litre if you still need a dose string printed on Amazon.
Pros
Cons
Best for: You already use Formulex and want the lower price per litre in a bottle whose volume fields agree.
Less suitable: A first bottle, when you need the 1:99 field that the 1 litre listing prints.
Specifications
Common questions
Is the 5 litre the same Formulex as the 1 litre listing?
The title and bullets match the 1 litre Formulex listing: seedlings, foliar feeding, Rockwool, and a buffered pH. This listing is the 5 litre size, priced at £29.89, with country of origin the United Kingdom.
What dose does Amazon print for this size?
The mixing-ratio field is not a usable figure. The stored notes do not give millilitres per litre.
Do the reviews mention the bottle opening?
One of the six UK texts says it works but the opening could pour better. The other texts do not mention leaks.
This generic bottle is listed at £5.56 with a 50 ml title, and the star line is 4.0 from one review. The stored notes have that star line only and no review text, so nothing on the page describes a plant, a leak, or a finished mix. Item form and included components both say refer to the description. The mixing-ratio field is 1:50, which you cannot check against a label the listing does not show. Title and liquid volume say 50 ml, the unit count says 1.0 millilitre, and the weight is 68 g, so the pack is not one figure. Country of origin is China. It is the cheapest row in the set, and it is also the row with a single star and a unit count that clashes with the title.
Pros
Cons
Best for: Only if you already know this bottle from somewhere other than the listing and you accept a 50 ml claim beside a 1 ml unit count.
Less suitable: A first hydroponic feed, or any job where you need English instructions and a review that describes a plant.
Specifications
Common questions
How much liquid does the listing actually specify?
The title and the liquid-volume field say 50 ml. The unit-count field says 1.0 millilitre. The item weight is 68 g.
Is the form given?
No. Item form and included components both say refer to the description. The mixing-ratio field is 1:50.
Are there any review comments?
The listing shows 4.0 from 1 review. The stored notes have the star line only and no review text.
CANNA Aqua Flores A and B is listed at £23.01 as a 1 litre set, and the bullets name recirculating hydroponic systems and flowering, not seedlings. The amazon.co.uk line is 3.9 from 9 reviews. The stored notes contain one United Kingdom text, and that text is only the word Good. Mixing ratio, part number, and item weight are all missing. Unit count and liquid volume both say 1 litre, and the title says 1 litre A and B, so the volume fields agree even though the reviews do not describe a crop. The manufacturer field says hydroponics4less. Read this label if your tank returns the solution and you are in flower, and treat nine reviews and one word as a thin file rather than a result.
Pros
Cons
Best for: You already run a recirculating system and you are in flower, and you will take the rate from CANNA rather than from this Amazon page.
Less suitable: Seedlings, coco as the main medium, or anyone who wants a large UK review file before spending £23.01.
Specifications
Common questions
Which hydroponic system do the bullets name?
Recirculating hydroponic systems. The bullets describe a flowering nutrient that dissolves directly and mention silicon, humic acids, and fulvic acids.
Is a mix rate printed on Amazon?
No. Mixing ratio, model number, part number, and item weight are all missing. Unit count and liquid volume both say 1 litre, and the title says 1 litre A and B.
What do the stored reviews say?
The listing shows 3.9 from 9 reviews. The stored notes contain one UK text, and that text is only the word Good.
The Qzdtue bottle is titled as 110 ml of hydroponic plant food at £9.09, and the only amazon.co.uk review scores it 1.0. That United Kingdom text says the label instructions are entirely in Chinese, there is no box, and £9 felt high for the small bottle. Amazon has no mixing-ratio field. The application line only says drop into water. The title says 110 ml, the unit count says 1.0 millilitre, liquid volume is empty, and the weight is 163 g. Item form says refer to the description, and the country of origin is China. You cannot follow a dose from this listing, which is why a single low star sits under the pack clash rather than above it.
Pros
Cons
Best for: A buyer who already reads the Chinese label and only wanted a tiny top-up they have used before.
Less suitable: Anyone in the UK who needs a dose in English, a unit count that matches 110 ml, or more than one review.
Specifications
Common questions
Can you follow a dose from this listing?
Amazon has no mixing-ratio field. The only UK review says the label instructions are entirely in Chinese and there is no box. The application line only says drop into water.
Does the size on the title match the unit count?
The title says 110 ml. The unit count says 1.0 millilitre. Liquid volume is not filled in. The item weight is 163 g.
What did the review say about using it?
One review, scored 1.0, says the buyer could not tell how to use it because the label was only in Chinese, and that £9 felt high for the small bottle.
Nouri is listed at £6.99 as 50 ml of concentrated A and B, and the stored notes have no customer-review line and no review text, so the score stays at 0. The title describes a liquid concentrate. The item-form field says granules. Liquid volume is empty, the unit count is 1.0 count, and the weight is 50 g. There is no mixing-ratio field. The bullets say the formula is simple to mix, water-soluble, and pH-balanced, and they do not give millilitres per litre. Country of origin is China, and the included line says a and b nutrients. You cannot tell from this page whether a parcel holds liquid, granules, or a dose you can measure.
Pros
Cons
Best for: Only a buyer who has already checked the bottle contents away from this listing.
Less suitable: Anyone choosing a first A and B set from the Amazon page alone.
Specifications
Common questions
Is the listing form a liquid or granules?
The title describes 50 ml concentrated A and B plant food. The item-form field says granules. Liquid volume is empty and the unit count is 1.0 count. The weight is 50 g.
Does Amazon print a mix rate?
No. There is no mixing-ratio field. The bullets say the formula is simple to mix and that it is water-soluble and pH-balanced. They do not give millilitres per litre.
Is there a star rating?
The stored notes have no customer-review line and no review text.
Eight amazon.co.uk listings were scored from the stored pages and the review notes already on those rows. Shelf date 21 October 2026. The Royal Horticultural Society, CANNA UK, Growth Technology and the BioBizz sheet are context for system and dose. They are not a score, and no NPK is copied in. The number on each card is the amazon.co.uk star rating times 20. A 4.7 line is 94. A missing star line stays 0. Pack clashes stay visible and are not averaged away. Two rows share 94. The top pick is the coco A and B set, because the listing is a two-part coco nutrient. The fish emulsion shares that score and has the larger review count, and it does not take the badge: the highlight also names soil, the weight clashes with the title, and the ratio field is 1:0. The best value is the lowest shelf price at the next score, 92. One of each. Neither badge is the right bottle for every system in the UK. The weights below are the buying checks used to read the set. They sum to 100. They are not a second league table.
System match
30%A complete feed for the system you run. One bottle for seedlings and LECA. Coco A and B for coir. A recirculating bloom formula only when the maker names that system. A fish emulsion that also names soil is not the coco set.
Readable dose
25%An English dose in millilitres per litre. A Chinese-only label, a 1 ml unit count against a larger title, a 1:1 field that is not a chart, and a 1:0 field fail this check. They do not change the star score.
Growth stage
15%Seedling and all-purpose formulas are gentler. Flowering A and B is not a whole-life feed. A high-nitrogen fish emulsion is a vegetative tool, and the maker sheet says to leave it when flowering should start.
Amazon evidence
20%The card number is the star rating times 20. A large UK review file is preferred to a single star with no text. Nine reviews and the word Good are not a verdict. The count does not alter the star score.
Price after the match
10%Price per litre only after the system matches. Best value is the lowest shelf price at the next score, 92. The 5 litre bottle is cheaper per litre and stays unbadged because the dose field is not usable.
Match the system and the dose before you match the star line. A one-part solution, a coco A and B set, a recirculating bloom set and a fish emulsion are not one list. Prices below are amazon.co.uk shelf prices in this capture, dated 21 October 2026. This is not a laboratory test.
Hydroponic fertiliser is a plant food you dissolve in water because the roots are not in garden soil. On amazon.co.uk the shelf mixes one-part mineral solutions, two-part A and B nutrients for coco or for recirculating systems, and organic emulsions that also name hydroponics. Quality is a readable English dose in millilitres per litre, a named system, and a base nutrient rather than a booster. A star line is not a yield trial.
Both bottles can say hydroponic. Coco A and B is for coir. A bloom set that names recirculating systems is for a tank that returns the solution, and it is not a seedling feed. A lower coco price does not fix that mismatch.
Stir A into the water before B. Do not pour the concentrates into each other. CANNA's 30 ml of A and 30 ml of B per 10 litres belongs to Aqua Flores. Formulex is 10 ml per litre in hydroponics on the maker's guide. Fish-Mix is 1 to 4 ml per litre on the maker's sheet.
A title of 50 ml or 110 ml beside a unit count of 1 ml is not one volume. A label only in Chinese, a granules field on a millilitre title, and a star line with no review text do not give you a dose. Nine reviews and the word Good are not a verdict.
Name the system before the price. One bottle is for seedlings, a small kit, LECA, soil or a foliar spray. Formulex is that one-part mineral solution, and the bullets also name Rockwool pre-treatment. Coco A and B is for coir across growing and flowering, and the Amazon field 1:1 is not the feed chart. Aqua Flores names recirculating systems and flowering. It does not name seedlings. Fish-Mix is a nitrogen-rich vegetative feed for soil and coco. The highlight also says hydroponics.
You need a dose in millilitres per litre that you can read in English. Growth Technology's guide is 10 ml of Formulex per litre in hydroponics and 5 ml per litre in soil or as a foliar spray. The 1 litre Amazon field says 1:99. The 5 litre field is not a usable figure, even though the volume fields agree and the origin is the United Kingdom. CANNA Aqua Flores is 30 ml of A and 30 ml of B per 10 litres. That line is not on the Amazon card, which has no mixing ratio.
Three typical situations, each with a recommendation from this comparison.
You want a small dose of a one-part feed, and smell matters indoors. Growth Technology Formulex, 1 litre, is about £11.77, with 4.6 from 140 reviews. The mixing-ratio field is 1:99. The maker's guide is 10 ml per litre in hydroponics and 5 ml per litre in soil or as a foliar spray. The number-of-items field says 1000 against one bottle.
You need a chart and a split between seedlings and bloom. CANNA Coco A and B, 1 litre set, is about £17.56 and 4.7 from 1,969 reviews. The listing is a two-part coco nutrient for growing and flowering. The Amazon ratio is 1:1, which is not a millilitre chart. Follow the maker's chart. Two of 50 stored UK reviews say the B bottle instructions are in French.
The tank returns the solution and you are in flower, not at the seedling stage. CANNA Aqua Flores A and B, 1 litre, is about £23.01. The bullets name recirculating systems and flowering. amazon.co.uk shows 3.9 from 9 reviews, and the only stored UK text is the word Good. There is no mixing-ratio field. CANNA states 30 ml of A and 30 ml of B per 10 litres, with A stirred in first.
The top pick for coco is CANNA Coco A and B, 1 litre set, at about £17.56. amazon.co.uk shows 4.7 from 1,969 reviews, and the listing is a two-part coco nutrient. The best value is Growth Technology Formulex, 1 litre, at about £11.77, 4.6 from 140 reviews, the lowest price at that score, with a mixing-ratio field of 1:99. BioBizz Fish-Mix shares the 4.7 line and has 2,059 reviews, and it stays unbadged because the item weight is 227 g against a 1 litre title and the ratio field is 1:0. CANNA Aqua Flores is the recirculating flowering set, at about £23.01, with 3.9 from 9 reviews. None of these scores is a laboratory test.
Growth Technology Formulex, 1 litre
Lowest shelf price at the next score, about £11.77, 4.6 from 140 reviews, with a 1:99 ratio field.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Public UK and maker sources used for this page in October 2026. Prices, stars and review counts are from the eight amazon.co.uk listings. Shelf date 21 October 2026. The card score is the star line times 20, not a laboratory test. No NPK is stated, because none of these listings print one. A fish-emulsion sheet is not a UK organic certificate.
Expert source (DIY & tools): Lee Burkhill (Garden Ninja) (external profile) – public expert commentary used as a research source, not as a contributor to our pages.
This page contains affiliate links to amazon.co.uk (tag pcuk26-21). If you buy through them, we may earn a commission at no extra cost to you. Prices, stars and review counts are from the listings. This is not a laboratory test.
