The best geranium fertilisers, compared.
Top pick: Cultivers organic geranium and flowering plant fertiliser 250 g – Highest score: granules, NPK 8-1-5, 74% organic matter, 5.0 from 2 reviews, about £11.62. Two reviews are too few for a UK trial. Best value: Cultivers organic geranium and flowering plant fertiliser 1 kg – About £15.53 for 1 kg of the stated 8-1-5 line, against about £11.62 for 250 g. A few pots do not finish 5 litres. Updated October 2026.
Geranium fertiliser is the feed you buy for a pelargonium in a pot, trough or hanging basket. The Royal Horticultural Society reserves Geranium for hardy cranesbills, and on most garden soils those plants are not fed unless a deficiency shows. The two do not share a regime. You judge a pack by the stated NPK, by whether you will repeat a liquid or rely on a granule release claim, and by whether the size matches the containers you have. A liquid is applied more than once in the season. A granule claim of slow or once-a-year release stays the seller's wording until the label shows a coating and a dose. Once flowers form, the RHS points pelargoniums to a high-potassium liquid. A higher-nitrogen ratio is a different job. How the names split is in the [pelargonium or hardy geranium guide](/hub/fertiliser-soil-and-bark-mulch/geranium-fertiliser/sub/geranium-fertiliser-pelargonium-or-hardy). A few pots do not need a large can or a heavy sack. Organic, vegan and pet-safety lines are manufacturer claims unless a UK certifier is named.
Geranium fertiliser is the feed you buy for a pelargonium in a pot, trough or hanging basket.
28 products checked · 61 hrs invested · +22,100 readers
Swipe for more
1-2 of 8
Personal buying guide
Question 1 of 2
How many containers are you feeding?
The Cultivers 250 g pack is listed as granules at about £11.62, with NPK 8-1-5, 74% organic matter and humic acids on the amazon.co.uk page. That nitrogen-heavier ratio is the flowering-plant line in this set, not the 4-1-7 liquid. Two reviews give it 5.0, and there is no review text, so the star line is a count rather than a description of flowers or leaf scorch. The title says 100% organic and vegan origin, and no UK certifier is named, so those words stay seller claims. No dose is printed, which means you still read the carton before you scatter it on a pot. At this size it suits a few containers, though 8-1-5 prints more nitrogen than the high-potassium pattern the RHS suggests once pelargoniums are in flower. The score of 100 is the star rating scaled up, and two reviews are too few to treat that as a tested result.
Pros
Cons
Best for: A few pots of pelargoniums when you want a small pack with a printed 8-1-5 ratio.
Less suitable: Anyone who needs a stated dose, a large review sample, or a high-potassium liquid once flowers are out.
Specifications
Common questions
Is this the granule or the liquid?
The item form is granules. The stated NPK is 8-1-5, with 74% organic matter and humic acids on the listing.
Does the listing name a vegan claim?
The title and bullets say 100% organic and vegan origin, and vegetable origin. No certifier is named.
What is the star line?
5.0 out of 5 from 2 reviews on the amazon.co.uk listing. No review text is on the listing.
Fertiligène Osmocote Max is a 700 g tub of granules at about £23.00, model OSGERN, from Evergreen Garden Care. The listing claims one application for a year, with uncoated granules plus resin-coated granules, and a window of February to June. The product data prints no NPK, so you cannot choose it for a ratio. The dose that is printed is about 20 g per handful, 3.5 handfuls per square metre in the ground, and 3 to 6 g per plant in a pot. Coverage is claimed at up to 175 plants. Across 129 reviews the line is 4.7, the largest sample here, though most of those reviews were marked in France and are not British comments. A field says number of items 12 beside a 700 g unit count, and it does not explain the 12, so do not read it as twelve tubs.
Pros
Cons
Best for: Pelargoniums in pots if you want a stated gram dose and will not repeat a liquid.
Less suitable: Buyers who need a printed NPK, or a high-potassium liquid after the June window on the listing.
Specifications
Common questions
What NPK does the listing give?
No N-P-K numbers are in the product data. A nutrients question on the page has no answer.
What dose does the listing print for pots?
About 20 g per handful, 3.5 handfuls per square metre in the ground, and 3 to 6 g per plant in a pot. Spread, scratch in, and water.
What does number of items 12 mean?
The listing says number of items 12 and unit count 700 g. It does not explain the 12. Do not treat it as twelve tubs.
The 1 kg Cultivers pack is about £15.53 with NPK 8-1-5, 74% organic matter and humic acids, and Ecoforce as manufacturer. Item form is not stated on this listing, so you should not copy granules from the 250 g listing onto it. Six reviews average 4.4. The only review body is marked in Belgium and says the notice recommended once a month while the reviewer applied twice a month, which is one person's habit, not a UK rate. That extra mass costs about £4 more than the 250 g pack, so the unit price is the stronger figure on the 8-1-5 line if you will use the bag. Vegan origin is a listing claim without a named UK certifier. No application rate is printed.
Pros
Cons
Best for: Several pots if you want more of the 8-1-5 line without a 20 kg sack.
Less suitable: Readers who need a confirmed granule form, or a high-potassium liquid once flowers form.
Specifications
Common questions
Is the 1 kg pack described as granules?
This listing has no item-form line. Do not copy the granule form from the 250 g listing onto this pack.
What NPK and organic-matter figures are printed?
The listing says NPK 8-1-5, 74% organic matter and humic acids, and claims vegan vegetable origin.
What does the only review say about the rate?
The review, marked in Belgium, says the notice recommends once a month and that the reviewer applied twice a month. Stars are 4.4 out of 5 from 6 reviews.
The 5 litre Cultivers liquid is about £35.29 and states NPK 4-1-7, the same micronutrient list as the 1 litre bottle, and amino acids called a biostimulant. Ecoforce is the manufacturer and the part number is ECO10F00257. Six reviews average 4.4, and there is no review text, so praise and criticism are not described. A bullet says 100% natural and harmless to animals. That remains a listing claim, and the pet question has no separate answer. At about £7.06 per litre it undercuts the 1 litre bottle if you will use the can on many baskets. Dilution is still absent. Five litres is a heavy buy for three pots on a balcony.
Pros
Cons
Best for: Many baskets or a run of patio pots you will feed through the season.
Less suitable: A balcony with three plants, or anyone who needs a gram dose.
Specifications
Common questions
What pack size and NPK are stated?
The title and unit count are 5 litres. The listing says an NPK 4-1-7 solution.
Does the listing claim it is harmless to animals?
A bullet says 100% natural and harmless to animals. The pet-friendly question has no separate answer.
Are there review comments?
The star line is 4.4 out of 5 from 6 reviews. No review text was on the listing, so praise and criticism are not described.
The 1 litre Cultivers liquid is about £15.86 and states an NPK 4-1-7 solution, with boron, calcium, iron, manganese, molybdenum and zinc named, plus amino acids described as a biostimulant. Ecoforce is the manufacturer. Five reviews average 3.9, the lowest star line among the rated liquids in this set, and the only review body is marked in Spain, so it is not a British comment. No dilution is printed, which leaves the physical label as the rate. At about £15.86 per litre it costs far less per litre than the 250 ml bottle and far more than the 5 litre can. The organic line is 100% organic and natural, again without a certifier. It is a workable mid-size 4-1-7 bottle if you will measure from the label, and a weak pick if you wanted a large UK review sample.
Pros
Cons
Best for: A season of liquid feeding for a modest number of pots, measured from the label.
Less suitable: Anyone who wants a printed gram dose or a stronger UK review count.
Specifications
Common questions
What NPK does the 1 litre listing state?
The listing says an NPK 4-1-7 solution. It also names boron, calcium, iron, manganese, molybdenum and zinc.
Is a dilution printed?
No application rate is on the listing. The physical label is still the rate to follow.
What do the stars refer to?
The amazon.co.uk aggregate is 3.9 out of 5 from 5 reviews. The only review body is marked reviewed in Spain.
The 20 kg Cultivers pack is about £60.42, about £3.02 per kilogramme, with listing bullets that say NPK 8-1-5, 74% organic matter and humic acids. One review, marked in Spain, says every fertiliser from this supplier is NPK 8-7-5, and both figures stay rather than one being chosen. Item form is not stated, so this is not automatically the granule tub scaled up. Two reviews average 3.2, the weakest star line in the set, and the only review body does not praise the product. Twenty kilograms is the wrong sack for a balcony of window boxes. The vegan and organic lines are listing claims without a named certifier, and no dose is printed.
Pros
Cons
Best for: A large planting only if you can accept the unresolved NPK figures.
Less suitable: Balconies, baskets, and anyone who needs one agreed ratio.
Specifications
Common questions
Which NPK should you use?
The listing bullets say NPK 8-1-5. One review, marked in Spain, says every fertiliser from this supplier is NPK 8-7-5. Both statements stay.
Is the form stated?
There is no item-form line on this listing. The title is the 20 kg size. Do not assume granules from a sister listing.
What is the star line?
3.2 out of 5 from 2 reviews. The only review body does not praise the product.
This 250 ml Cultivers liquid is about £13.51, and the model field reads NPK 4-1-7, which is the potassium-leaning ratio among the Cultivers bottles. The amazon.co.uk listing has no star line and no review text, so there is no UK rating to weigh against the other packs. Micronutrients are mentioned in the title only, and the elements are not listed, unlike the 1 litre and larger bottles. Manufacturer is absent on this listing, while Ecoforce appears on the bigger packs. A page question asks whether it is safe for pets, and there is no answer. At about £54 per litre it is the dearest liquid in the set by volume, which only makes sense if you will finish a small bottle on a handful of pots. Dilution is not printed, and the organic line is a title claim with no certifier named.
Pros
Cons
Best for: A small 4-1-7 bottle when you will not finish a litre.
Less suitable: Buyers who want a star rating, a named manufacturer, or a lower price per litre.
Specifications
Common questions
Does this 250 ml listing state an NPK?
The model number field is NPK 4-1-7. There is no further nutrient paragraph beyond the title.
Are the micronutrients named?
The title says macronutrients and micronutrients. The individual elements are not listed.
Does the listing say it is safe for pets?
The page asks whether it is safe for pets. There is no answer text and no harmless-to-animals bullet.
The 10 litre Cultivers liquid is about £54.59, listed at 12.5 kg, with NPK 4-1-7 and the same named trace elements as the 5 litre can. There is no customer-review line and no review text, so the score sits at zero for lack of a star line rather than because of a bad rating. The coverage field is the bare figure 10 with no unit, and that must not be read as coverage of 10 litres. The pack itself is 10 litres. Unit price is about £5.46 per litre, the lowest liquid rate in the set. You still have no dilution, and a 12.5 kg can is awkward to store in a flat. It only pays if you have enough pelargoniums to finish it in a season.
Pros
Cons
Best for: A large collection of baskets if you can store 10 litres.
Less suitable: A few pots, or anyone who wants Amazon reviews before buying.
Specifications
Common questions
What does the coverage field of 10 mean?
The coverage value is the bare figure 10. The unit is not stated. Do not read it as coverage of 10 litres. The pack itself is 10 litres.
Which micronutrients are named?
The bullets name boron, calcium, iron, manganese, molybdenum and zinc, plus amino acids described as a biostimulant.
Is there an Amazon star rating?
No customer-review line and no review text are on the listing.
Eight amazon.co.uk listings were scored as the star rating multiplied by 20. A listing with no star line scores 0. Shelf date 19 October 2026. There is no laboratory test. No extra deduction was applied, so a score of 100 from two reviews is the star line scaled up, not a UK trial. The top pick is the highest score. The best value is the 1 kg pack because about £15.53 buys 1 kg of the stated 8-1-5 line against about £11.62 for 250 g, and a few pots do not finish 5 litres. The 20 kg sack is cheaper per kilogramme only with an 8-1-5 versus 8-7-5 conflict still open. Organic, vegan and pet lines stay listing claims. The Osmocote NPK stays unset. The weight below is the whole numeric score.
Amazon star line
100%The score is the amazon.co.uk star rating times 20. The Cultivers 250 g pack is 5.0 from 2 reviews, so 100. Osmocote Max is 4.7 from 129, so 94, and it takes no badge because the product data has no NPK. The 1 kg pack and the 5 litre liquid are both 4.4 from 6, so 88. The 1 litre liquid is 3.9 from 5, so 78. The 20 kg pack is 3.2 from 2, so 64. The 250 ml and 10 litre liquids have no star line, so 0. Review counts stay on the rating. French, Spanish and Belgian review bodies are not treated as British comments.
Name the plant, then the form, then the pack size. A hardy cranesbill and a basket pelargonium are not the same job. Prices below are amazon.co.uk shelf prices on 19 October 2026. This is not a laboratory test.
Geranium fertiliser on amazon.co.uk is a liquid or a granule pack for the plants UK gardeners call geraniums. Most of those plants in pots, troughs and hanging baskets are pelargoniums. The Royal Horticultural Society uses Geranium for hardy cranesbills. Those two plants do not share a feeding regime. On most garden soils a hardy cranesbill is not fed unless a deficiency shows. A pelargonium in a container is fed, because the compost runs out. Naming the plant comes before the pack size.
The RHS uses Geranium for hardy cranesbills and Pelargonium for the tender plants sold as geraniums. A border cranesbill on most soils is not a routine feed. A pot pelargonium is.
The 700 g tub states a dose and a one-year claim. It does not state an NPK. The year line stays the listing's claim. Cultivers slow and controlled is not that resin coating.
The bullets say 8-1-5. One review, marked in Spain, says 8-7-5. Both stay. The sack is also far more than a few pots need, and the form is not stated.
Pelargoniums in pots are fed. Hardy cranesbills on most garden soils are not, unless a deficiency shows. The RHS says so. Once flowers form, the RHS points pelargoniums to a high-potassium liquid. In this set the liquids state 4-1-7 and the flowering-plant packs state 8-1-5, which prints more nitrogen. Neither ratio is an RHS prescription. The 20 kg bullets say 8-1-5 and a Spanish review says 8-7-5. Keep both. The Osmocote listing has no NPK, so it is not a choice you make on analysis.
A liquid is repeated. Osmocote Max states one application, uncoated granules plus resin-coated granules, 3 to 6 g per pot, and February to June. Cultivers slow and controlled is the seller's phrase, not that coating. A few pots suit 250 g or 250 ml. Many baskets can justify 5 litres if you will finish the can. Ten litres and 20 kg are the wrong buy for a balcony. Organic, vegan and harmless-to-animals lines name no UK certifier and stay listing claims.
Three typical situations, each with a recommendation from this comparison.
A handful of pelargoniums does not need 5 litres or 20 kg. The Cultivers 250 g pack is the top pick at about £11.62, with granules and NPK 8-1-5 stated, and 5.0 from 2 reviews. Two reviews are too few for a trial, and no dose is printed. The 250 ml 4-1-7 liquid is the small bottle if you will repeat a liquid, at about £54 per litre.
Fertiligène Osmocote Max is the 700 g tub at about £23.00. The listing states one application for a year, a February to June window, and 3 to 6 g per pot. That year line is the listing's claim. There is no NPK in the product data. It is 4.7 from 129 reviews, and most of those reviews were marked in France.
The 5 litre Cultivers liquid states NPK 4-1-7 at about £35.29, about £7.06 per litre, with 4.4 from 6 reviews and no review text. It suits a run of patio pots you will feed through the season. Dilution is not on the listing, so the label still sets the rate. Ten litres is only worthwhile if you can store 12.5 kg.
The top pick for a few pots is the Cultivers 250 g pack at about £11.62. The listing states granules, NPK 8-1-5 and 74% organic matter, and amazon.co.uk shows 5.0 from 2 reviews. That score is the star line scaled up, and two reviews are too few for a UK trial. The best value is the Cultivers 1 kg pack at about £15.53, about four times the weight for roughly £4 more on the same stated 8-1-5 line. Form is not stated on that listing. Osmocote Max has the largest review file, 4.7 from 129, a printed pot dose of 3 to 6 g, and no NPK in the product data. The 5 litre 4-1-7 liquid is the can for many baskets if you will finish it. The 20 kg pack keeps both 8-1-5 and a review that says 8-7-5. None of these scores is a laboratory test.
Cultivers organic geranium and flowering plant fertiliser 250 g
Highest score: granules, NPK 8-1-5, 74% organic matter, 5.0 from 2 reviews, about £11.62. Two reviews are too few for a UK trial.
Cultivers organic geranium and flowering plant fertiliser 1 kg
About £15.53 for 1 kg of the stated 8-1-5 line, against about £11.62 for 250 g. A few pots do not finish 5 litres.
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 sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the eight amazon.co.uk listings captured on 19 October 2026. Organic, vegan and pet-safety lines are listing claims. The one-year granule line is the listing's claim, not a laboratory result. French, Spanish and Belgian reviews are not British comments.
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.
