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Tomato fertiliser buying guide: checks before you pay

Updated: October 2026

A 3 litre bottle can be a smaller supply than a 1 litre concentrate, and the price will not tell you which you are holding. The sticker, the star line and the word seaweed hide the format, the analysis and whether a spray sits in the parcel. This tomato fertiliser buying guide is the set of checks before you pay. The [tomato fertiliser comparison](/hub/fertiliser-soil-and-bark-mulch/tomato-fertiliser) keeps the twelve amazon.co.uk rows. Products Compared editorial team read those listings on 15 October 2026 and did not run a feeding trial. A qualifying purchase through our links can earn a commission at no extra cost to you.

A 3 litre bottle can be a smaller supply than a 1 litre concentrate, and the price will not tell you which you are holding.

Our top picks

Topline Topline tomato feed bundle with bug spray

Best overall

Topline Topline tomato feed bundle with bug spray
7.5/10about £20.99
View offer
Doff Doff Tomato Feed 1 L

Rank 2

Doff Doff Tomato Feed 1 L
9.2/10about £5.30
View offer
Doff Doff Tomato Feed 2.5 L

Preis-Tipp

Doff Doff Tomato Feed 2.5 L
8.8/10about £12.18
View offer
On this page
  1. 1.Concentrate or already mixed
  2. 2.What the NPK line must say
  3. 3.Made-up litres, not bottle litres
  4. 4.Organic mark and the spray

Concentrate or already mixed

Buy the format before the sticker. A concentrate is a small volume you dilute into a watering can. A ready-to-use bottle is already mixed, and the pack is the whole supply. Doff's 1 litre concentrate is £5.30, and the bullets say 1 litre makes 300 litres. PowerGrow's 4 litre bottle is £12.12, and the extract prints no rate. Hygeia's page says 1 litre of Powergrow makes 143 litres. That line is not on the amazon.co.uk extract, so do not pay as if Amazon had promised it.

What the NPK line must say

The third number is potassium. If the Amazon extract prints no analysis, you are buying a star count. The best tomato feed UK page says who can still take a blank listing, and who should leave it.
Topline Topline tomato feed bundle with bug spray

Testsieger

Topline Topline tomato feed bundle with bug spray
7.5/10about £20.99
View offer

Made-up litres, not bottle litres

Compare the litres you will pour, not the litres in the plastic. Doff's 1 litre at £5.30 for 300 litres is about 1.8p per made-up litre. The 2.5 litre at £12.18 for up to 750 litres is about 1.6p. Maxicrop at £11.99 for up to 200 litres is about 6p. The 2.5 litre mixing field says 466:1, which does not describe 750 litres. The 500 ml Doff bottle is £4.90, or £9.80 per litre of concentrate, and the weight field says 99.8 g, which cannot describe 500 ml of a water-based liquid. Levington's own page, not the Amazon extract, says 1 litre of Tomorite makes 225 litres. The how to use tomato fertiliser page is where the can belongs.

Organic mark and the spray

Only Maxicrop's bullets here name OF&G. If that mark is why you would pay £11.99, read the organic or standard tomato feed page before you treat seaweed as a certificate. Levington's page uses 20 ml in 4.5 litres for tomatoes and 10 ml for peppers and aubergines.

Common questions

What should the third NPK number do?
The third figure is potassium. You choose a tomato feed because that figure sits higher than the nitrogen figure, so fruiting is favoured over soft leaf. Big Tom's model field is 6-3-9.5. Tomorite's model field is 4-3-8. Doff's 1 litre bullets say 4-5-9, while Doff's website currently says 4-2-10. If the extract prints no three-number line, you do not yet know the potassium figure.
Is a 3 litre bottle better value than a 1 litre concentrate?
Only if those 3 litres are concentrate, which Pour and Feed is not. Doff Pour and Feed at £6.53 is 3 litres of mix you pour. Doff's 1 litre concentrate at £5.30 is listed as making 300 litres. The larger-looking bottle is the smaller supply. It can still suit a few pots if you will not measure, and it is a weak buy for a greenhouse that needs a can every week.
Which listings print no NPK?
PowerGrow's 1 litre and 4 litre extracts do not. Doff Pour and Feed, Doff 2.5 litre, and Doff 500 ml do not. Topline's bundle does not. Big Tom, the Tomorite sizes in this set, and Doff's 1 litre bullets do print an analysis, and those analyses are not identical. A figure on Hygeia's site or a seed retailer's page is not the Amazon extract.
Is seaweed the same as an organic mark?
Seaweed on Tomorite, Doff, or Big Tom is an ingredient line. Maxicrop is the only row here whose bullets name a control body, OF&G, and the same page also mentions the Soil Association. Read the mark on the pack. Seaweed on its own does not turn the cheaper bottle into an organic feed. The two body names are not one certificate written two ways.
When is a bug spray in the parcel?
When the listing is Topline. The price of £20.99 covers two 1.2 litre feeds and an 800 ml spray. The other eleven listings in this comparison are feed only. The spray text states a 24-hour gap before picking and says to wash the produce. It does not print a MAPP number, so the pesticide label, not the fertiliser bullets, is the instruction for that bottle.
Why do three Doff sizes share one review count?
The 500 ml, 1 litre, and 2.5 litre Doff files in this batch show the same 4.5 from 1,156 reviews and the same review text. That is one parent scrape attached to three sizes. It is still a large block of opinion. It is not three separate tests. Do not add the counts together and treat the sum as extra evidence for a particular bottle size.
What if the website and the Amazon bullet disagree?
Follow the label on the bottle you are about to mix. Doff's 1 litre Amazon bullets say NPK 4-5-9 and 300 litres from 1 litre. Doff's concentrate page currently says NPK 4-2-10. Both can sit on a screen at once, and only the pack in your hand is the analysis you should trust. The same caution applies when Amazon says 2.5 caps and Doff's Pour and Feed page says 100 ml.

Related pages

Tomato feed or tomato compost

Tomato fertiliser

Best tomato feed UK: the right bottle for your plants

Tomato blossom end rot: fertiliser is not the first fix

How to use tomato fertiliser without doubling the dose

Organic or standard tomato feed: what the label proves

Sources

Public UK and manufacturer sources used for this comparison; last accessed 15 October 2026.

  1. RHS: Tomatoes, grow your own (retrieved 15 October 2026)
  2. RHS: Blossom end rot (retrieved 15 October 2026)
  3. RHS: Storing and disposing of garden chemicals safely (retrieved 15 October 2026)
  4. GOV.UK: Manufacturing and marketing fertilisers (retrieved 15 October 2026)
  5. GOV.UK: Product regulations and UKCA and CE marking (retrieved 15 October 2026)
  6. HSE: Using pesticides in the garden and home (retrieved 15 October 2026)
  7. Levington Tomorite concentrated tomato food (retrieved 15 October 2026)
  8. Doff tomato feed concentrate (retrieved 15 October 2026)