The best Compo potting composts, compared.
Top pick: Compo Sana Confort universal 12 L Best value: Compo Sana Confort universal 12 L – Lowest price per litre at about £1.41, with a coherent 3.44 kg weight. The UK bullets state no feed window. Updated October 2026.
Compo potting compost is bagged growing medium for pots and planters. You buy it in the UK when a windowsill, balcony or patio container needs fresh mix. It is not a heap of garden compost and it is not a liquid feed. A suitable bag is the one whose litres match the pot, whose listing states a feed window if you want a printed one, and whose peat wording matches what you will accept. A pot about 20 cm across and 16 cm deep holds near 5 litres. General multipurpose mix is the wrong default for ericaceous plants, orchids and fine seed. You tell a peat-free claim from a bag that never mentions peat by reading the title, then the sack. An announced end to amateur peat sales in England is not a ban already in force. Litres, feed weeks and peat words are set out in the [Compo potting compost buying guide](/hub/fertiliser-soil-and-bark-mulch/compo-potting-compost/sub/compo-potting-compost-buying-guide). Fungus gnats breed in damp compost.
Compo potting compost is bagged growing medium for pots and planters. You buy it in the UK when a windowsill, balcony or patio container needs fresh mix. It is not a heap of garden compost and it is not a liquid feed.
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Personal buying guide
Question 1 of 2
How many pots are you filling?
Compo Sana Confort universal is the 12 litre bag at £16.92, about £1.41 a litre, which is the lowest price per litre in this comparison. The listed weight is a coherent 3.44 kg, unlike the 800 g clash on the 5 litre and 10 litre Sana pages. The star line is 4.6 from 787 reviews, the highest stars here, and every review in the raw sample of 50 is from Spain, so that figure is not British potting experience. The UK bullets do not state a feed window or peat, and a Spanish review says the page claimed 12 weeks while the bag said 6 weeks, which this file does not settle. Questions about indoor plants and organic compost are asked and left unanswered. It is the best value if you want the most litres for the money and can live with thin bullets.
Pros
Cons
Best for: Several pots or a patio when litres per pound come first and you will feed on your own schedule.
Less suitable: You need a stated week count, UK review text, or the words peat-free on the title.
Specifications
Common questions
How many weeks of feed does the 12 litre listing promise?
The UK bullets do not state a number of weeks. A Spanish review says the page claimed 12 weeks and the bag said 6 weeks. That conflict is not settled by this saved listing.
Does the listing say the mix is organic or peat-free?
No. The questions ask about a use-by date, indoor plants and organic compost, and the bullets do not answer them. Peat is not mentioned.
Is the 4.6-star score from UK buyers?
The listing line is 4.6 from 787 reviews on amazon.co.uk. Every review in this raw sample of 50 is from Spain.
The 10 litre Compo Sana listing is £27.43, about £2.74 a litre, with the same up-to-6-weeks line and an airy-structure bullet as the smaller Sana bag. A rough pot sum puts a 20 cm pot about 16 cm deep near 5 litres, so this sack is closer to two of those than the 5 litre bag is. The amazon.co.uk line is 4.5 from 4,912 reviews, yet only two of the 50 reviews in the saved listing are from the United Kingdom and 44 are from Germany. The bullets do not say peat-free, and they do not answer the drainage question the page itself asks. Item weight prints 800 g against a unit count of 3,830 g, which is not a plausible checked weight for 10 litres. Take it when you want the general Sana mix in a larger sack and you will not treat the German comments as British experience.
Pros
Cons
Best for: Repotting more than one small container on the general Sana line when the title does not need to say peat-free.
Less suitable: You want British review sentences, a peat-free sack, or the lowest price per litre.
Specifications
Common questions
Does the listing say this 10 litre bag drains well?
It asks the question and does not answer it. The bullets say an airy structure and optimal water uptake. They do not say yes or no to drainage.
Is the 800 g weight the weight of the bag?
The listing prints item weight 800 g and unit count 3,830 g. Those two figures conflict. 800 g is not a plausible checked weight for 10 litres.
Are the star ratings from UK reviewers?
The listing line is 4.5 from 4,912 reviews on amazon.co.uk. In the raw sample of 50, only two reviews are from the United Kingdom.
A 5 litre Compo Sana bag is about one 20 cm pot, or a couple of smaller houseplants, and the amazon.co.uk listing saved on 19 October 2026 prices it at £20.29, about £4.06 a litre. The bullets say nutrients for up to 6 weeks, and the star line is 4.5 from 4,731 reviews. Thirty-six of the 50 reviews in the saved listing are from the United Kingdom, which is the only large British sample in this set. Reviewers often say the bag is smaller than the photo, and one UK reviewer used two of these bags for a 30 cm pot. Peat is not stated, so this is not the peat-free option, and the item weight of 800 g conflicts with a unit count of 1,970 g. UK notes mention both fungus gnats and no bugs, and one UK reviewer reported mould with poor drainage. It is the top pick when you want a small Sana bag with a printed six-week feed and mostly British review text.
Pros
Cons
Best for: A flat or windowsill where you are repotting one or two plants and want the Sana line with a printed six-week feed.
Less suitable: Filling a 30 cm pot from one bag, a peat-free requirement, or the lowest price per litre.
Specifications
Common questions
Can this 5 litre bag be used indoors?
The listing asks that and does not answer it in the bullets. UK reviews in the saved listing include indoor repotting, succulents and herbs. One UK reviewer reported mould and poor drainage.
Does the listing say it is peat-free or organic?
No. The bullets state a nutrient supply for up to 6 weeks and water uptake. They do not say peat-free, and they do not say organic.
Why do the weights disagree?
Item weight is 800 g. Unit count is 1,970 g. Do not treat 800 g as a checked weight of the 5 litre bag.
The 5 litre Compo Sana for green plants and palms is £20.59, about £4.12 a litre, and the bullets say 8 weeks of nutrition, decorative leaves and a lot of water. That 8-week line is not the same figure as the up-to-6-weeks claim on the universal 5 litre and 10 litre Sana listings. The amazon.co.uk line is 4.5 from 1,887 reviews, and only three of the 50 saved reviews are from the United Kingdom. Those UK notes mention chives on a balcony rather than a palm, so the title's plant match is wider than the British sample proves. Listed weight is 1.98 kg against a 5,000 ml unit count, which agrees in a way the 800 g rows do not. Peat is not mentioned. Choose it for leafy indoor plants or a small palm when you want the longer printed feed.
Pros
Cons
Best for: Foliage or a small palm in a flat, where the bag name and the 8-week bullet match the plant.
Less suitable: A herbs-only job, ericaceous plants, orchids, or a buyer who needs peat-free on the title.
Specifications
Common questions
What plants is this 5 litre bag named for?
The title is green plants and palm soil. The bullets mention decorative leaves, a lot of water and 8 weeks of nutrition. UK reviews in the sample mention chives on a balcony, not a palm.
Does the listing say it is peat-free?
No. This listing does not mention peat. The bullets say 8 weeks of nutrition, decorative leaves and a lot of water.
Is 8 weeks the same as the 6 weeks on the universal Sana bags?
No. This listing's bullet says 8 weeks. The 5 litre and 10 litre Sana listings say up to 6 weeks. They are different lines.
The 7.5 litre bag titled peat-free bio universal is £26.41, about £3.52 a litre, and it is the only title in this set that says peat-free. The star line is 4.3 from 2,232 reviews, the lowest here, and all 50 reviews in the saved listing are from Germany. The manufacturer field reads TOM-GARTEN while the brand is Compo and the part is 11224, and the saved listing names no Soil Association number, so bio is a word on the title rather than a UK certifier. Listed weight is 3.17 kg, which sits more plausibly against 7.5 litres than the 800 g rows on the universal Sana bags. The only product bullet is the container size, so this amazon.co.uk page states no feed weeks. A German retailer text for article 11224 mentions feeding again after 2 to 5 weeks, and that sentence is not a promise on this listing. Buy it when the sack must say peat-free, and read the bag you receive.
Pros
Cons
Best for: You want the words peat-free on the title and can accept 7.5 litres without a printed week count.
Less suitable: You need UK review text, a Soil Association number, or the cheapest litres in this set.
Specifications
Common questions
Is this the peat-free bag in the set?
The title says peat-free bio universal. It is the only title here that says peat-free. The bullets do not list ingredients.
Does Bio on the title mean a UK organic certifier?
The saved listing does not name a certifier or a Soil Association number. Bio is the word in the title. The manufacturer field reads TOM-GARTEN.
How long does the listing say the feed lasts?
It does not. The only product bullet is the 7.5 litre container size. Questions about indoor use, ingredients and herbs are asked and not answered.
Five amazon.co.uk listings were scored from the stored pages and the country mix of the saved review samples already on file. Shelf date 19 October 2026. This is not a laboratory germination trial and not a Which? ranking. Star lines are not a measure of how a plant will grow in your flat. German and Spanish comments stay on file and do not count as British experience. The highest total is the top pick. The best value is the lowest price per litre, kept with the thin-bullet limit in the same note. The weights below sum to 100.
UK-usable review evidence
35%Share of the raw sample written from the United Kingdom. German and Spanish comments stay in the file and do not count as British experience. The 5 litre Sana bag has 36 of 50 reviews from the United Kingdom. The foliage bag has 3 of 50 and the 10 litre bag 2 of 50. The 12 litre sample is Spanish and the peat-free sample is German.
Listing facts you can act on
30%A stated feed window, a weight field that agrees with the volume, and whether that title actually says peat-free. The 5 litre and 10 litre bags state up to 6 weeks but print 800 g against higher unit counts. The foliage bag states 8 weeks and 1.98 kg. The 12 litre and peat-free bullets state no weeks. Only the peat-free title says peat-free.
Amazon star line
15%Stars and review count on the amazon.co.uk line, capped when the written sample is not British. The lines are 4.5 from 4,731, 4.5 from 4,912, 4.6 from 787, 4.5 from 1,887 and 4.3 from 2,232. A high star row with a Spanish or German sample does not score as British experience.
Price per litre
20%Shelf price on 19 October 2026 divided by the stated litres. About £1.41 a litre takes the full block. About £4.12 sits at the bottom of this set. The 12 litre bag is about £1.41 a litre. The foliage 5 litre bag is about £4.12.
Buy litres, peat wording and a feed window before you buy the star line. Prices below are amazon.co.uk shelf prices on 19 October 2026. This is not a laboratory test, and a UK peat ban is not in force.
Compo potting compost on amazon.co.uk is bagged growing medium for containers. It is not garden-heap compost and it is not a liquid feed. You separate the bags by litres, by any stated feed window, and by whether the title says peat-free. A 5 litre bag is a flat or a couple of houseplants. A geometry rule of thumb: a 20 cm pot about 16 cm deep holds roughly 5 litres. One UK reviewer used two 5 litre bags for a 30 cm pot, so the photograph is a poor guide to how far the sack goes.
Reviewers of the 5 litre bag often say it is smaller than the picture. One UK reviewer used two 5 litre bags for a 30 cm pot. Match litres to the pot.
Item weight is 800 g on the 5 litre and 10 litre pages. The unit counts are 1,970 g and 3,830 g. Do not quote 800 g as a checked weight.
The 10 litre sample is mostly German, the 12 litre sample is Spanish and the bio sample is German. Only the 5 litre bag has a large United Kingdom share in the saved listing.
Start with litres against the pot you are filling. A 5 litre bag is a flat or a couple of houseplants. A 20 cm pot about 16 cm deep holds roughly 5 litres. One UK reviewer used two 5 litre Sana bags for a 30 cm pot, which is why the photograph is a poor guide to volume. The 10 litre Sana bag is closer to two of those small pots. The 12 litre Confort bag is the largest here. The peat-free title is 7.5 litres. Buy litres you can store.
Read the stated feed window, then plan to feed. The 5 litre and 10 litre Sana listings say up to 6 weeks. The green plants and palms listing says 8 weeks. Those are different lines. The 12 litre bullets and the UK bio bullets do not state weeks. A German retailer text for article 11224 says feed again after 2 to 5 weeks. That sentence is not a promise on the amazon.co.uk listing. If the bullets give no window, feed on your own schedule from the start. Match the plant.
Three typical situations, each with a recommendation from this comparison.
You are repotting one or two plants and need litres you can store. Compo Sana potting soil 5 L is about £20.29, with nutrients stated for up to 6 weeks. Thirty-six of 50 saved reviews are from the United Kingdom. It is the wrong bag if the title must say peat-free.
You want the lowest price per litre in this set and can accept thin bullets. Compo Sana Confort universal 12 L is about £16.92, about £1.41 a litre, with a listed weight of 3.44 kg. The raw sample of 50 reviews is from Spain, and the UK bullets state no feed window.
You want the words peat-free on the title, and you will still read the sack. Compo peat-free bio universal 7.5 L is about £26.41. It is the only title here that says peat-free. The saved listing names no Soil Association number, the manufacturer field reads TOM-GARTEN, and all 50 saved reviews are from Germany.
The top pick is Compo Sana potting soil 5 L at about £20.29. It leads because 36 of 50 saved reviews are from the United Kingdom and the bullets state nutrients for up to 6 weeks. About £4.06 a litre and the 800 g weight conflict keep the score short of a full mark. The best value is Compo Sana Confort universal 12 L at about £16.92, about £1.41 a litre, with a coherent 3.44 kg weight. It ties the 10 L Sana on points and still takes the value award, because the raw sample is Spanish and the UK bullets state no feed window. The green plants and palms bag states 8 weeks. The 7.5 L title is the only one that says peat-free, and it finishes last on this score. None of these scores is a laboratory test.
Compo Sana Confort universal 12 L
Lowest price per litre at about £1.41, with a coherent 3.44 kg weight. The UK bullets state no feed window.
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 from the research digest, used for this page in October 2026. Prices, stars and review counts are from the five amazon.co.uk listings captured on 19 October 2026. A UK peat ban is not in force. German and Spanish review samples are not British customer experience. Bio on the 7.5 litre title is not a Soil Association number in the saved listing.
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.
