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Epsom salt fertiliser buying guide

Updated: October 2026

You have yellowing between the veins on older leaves, or you have not looked closely enough to know, and a bucket on amazon.co.uk looks cheap per kilogram. This epsom salt fertiliser buying guide is the checklist before you pay: the leaf, the department, the kilograms that agree, and whether magnesium oxide is actually declared. Shelf prices here are the GBP figures from the amazon.co.uk product data on 19 October 2026. The [Epsom salt fertiliser comparison](/hub/fertiliser-soil-and-bark-mulch/epsom-salt-fertiliser) holds the twelve ASINs, stars and clashes. Products Compared did not run a laboratory trial. A qualifying purchase can earn us a commission at no extra cost to you.

You have yellowing between the veins on older leaves, or you have not looked closely enough to know, and a bucket on amazon.co.uk looks cheap per kilogram.

Our top picks

Westland Westland Epsom salts 1.5 kg

Best overall

Westland Westland Epsom salts 1.5 kg
8.2/10about £7.50
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Vitax Vitax Epsom salts 1.25 kg

Rank 2

Vitax Vitax Epsom salts 1.25 kg
8.9/10about £8.50
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Hexeal Hexeal Epsom salt 5 kg

Alternative

Hexeal Hexeal Epsom salt 5 kg
7.7/10about £11.40
View offer
On this page
  1. 1.Check the leaf before the basket
  2. 2.Garden carton or Beauty listing
  3. 3.Kilograms and magnesium oxide
  4. 4.What the review count is actually counting

Check the leaf before the basket

Magnesium, when this salt is the right tool, shows as yellowing between the veins on older leaves. The Royal Horticultural Society describes that pattern and names tomatoes. Young leaves that yellow first follow the iron pattern, and a plant that is pale all over is closer to nitrogen. On a tomato in a grow bag, the lower leaves go yellow between green veins while the growing tip stays green. A black patch on the blossom end is a different fault, and that sits on Epsom salt fertiliser for tomatoes. When the mottling is limited to older leaves there may be no cause for concern.

Garden carton or Beauty listing

Westland B001P3SMQ0 and Vitax B003MPGFIG sit in Garden in the product data, at £7.50 and £8.50. Westland’s rank is 8 in Vegetable Plant Fertilisers. Vitax is 23. The Hexeal rows are Beauty bath salts. A garden bullet on a bath listing does not move that rank. Westland’s brand page says the carton is not for bathing or eating. That sentence is not in the amazon product data. Hexeal’s bullets lead with 250 g–1 kg in a warm bath and then a garden line. Food-grade wording is not a garden trial.
Westland Westland Epsom salts 1.5 kg

Testsieger

Westland Westland Epsom salts 1.5 kg
8.2/10about £7.50
View offer

Kilograms and magnesium oxide

Read the title, the unit count and the item weight as three separate lines. Westland’s title says 1.5 kg while item weight is 1.44 kg. Vitax B003MPGFIG’s title says 1.25 kg while item weight is 500 g. On B074CD8PBK the title says 2 × 1.25 kg and the unit count is still 1,250.0 gram. Hexeal’s 2.5 kg and 5 kg rows are the ones where title, unit count and item weight agree. No amazon row in this set prints an MgO percentage. According to the manufacturer, a Vitax sheet shows 16.6% MgO, and that figure is not on the amazon listing. Westland’s mixing field is 1:0:0, which is not a dose. Vitax’s 20g/l field is a mixing line, not that 16.6%.

What the review count is actually counting

Westland’s 4.6 from 1,463 and Vitax’s 4.5 from 675 are the large UK samples. In the Amazon reviews the saved texts are about leaves and tomatoes. Hexeal’s 2.5 kg and 5 kg pages share one 4.5 from 547 line and the same 50 UK texts. Most describe baths. That is one review file, not two garden tests. B074CHK28W and B072BJMNTS have no star line at all. If the leaf, the department, the kilograms and the declaration still disagree, the cheaper kilogram is not the purchase.

Common questions

Do I need yellowing between the veins before I buy?
You need that older-leaf pattern, or a note that already says magnesium, before this salt is the tool. The RHS describes yellowing between the veins on older leaves, sometimes reddish brown, and names tomatoes. If you have not checked which leaves changed, look first. Even pale growth and yellow young leaves point elsewhere. A green-up slogan on a listing is not the same check.
Is a Beauty bath-salt rank the same as a garden fertiliser?
No. The Hexeal ranks in the product data sit in Beauty, Bath Salts, even where a garden bullet names tomatoes and roses. Westland and the single Vitax carton sit in Garden. A bath rank can still be magnesium sulphate. It is not evidence that 547 people judged it as a plant feed, because that file is shared and mostly about baths.
What if the amazon page has no magnesium oxide line?
Magnesium on a fertiliser declaration is expressed as magnesium oxide, MgO. The RHS expects a nutrient declaration on a fertiliser label. None of the twelve amazon rows in the product data prints an MgO percentage. A manufacturer PDF can show 16.6%, and a Levington brand page can show 25%, and those figures stay on those pages until the amazon listing prints them. Do not paste them into the basket as if Amazon had declared them.
Why do a 2× title and a 1,250 g unit count disagree?
The title is a sales line and the unit count is a separate field. On B074CD8PBK the title says 2 × 1.25 kg and the unit count is 1,250.0 gram. On B074CHK28W the title says 3 × 1.25 kg and the unit count is again 1,250.0 gram, with item weight 1.25 kg. The clash stays visible. You cannot know from these fields alone that two or three cartons will arrive.
Is “suitable for organic gardens” a certification?
Not on these sources. Brand wording about organic gardens, or “organic magnesium”, is a sentence on a brand page. These listings do not name the Soil Association or another certifier. The RHS lists Epsom salts as an inorganic fertiliser, NPK 0–0–0 plus magnesium. Food-grade and vegan fields on Hexeal are not organic marks either.
Is a mixing field of 1:0:0 a rate?
No. On Westland B001P3SMQ0 the mixing field is 1:0:0, and that is not a grams-per-litre rate and not an MgO percentage. The brand page’s 20 g per square metre is a different document. If the amazon row has no grams, you do not invent them from 1:0:0.
Does 5.0 from two reviews outrank 4.6 from 1,463?
No. Five stars on one, two or five reviews is a thin sample. Westland’s 4.6 from 1,463 and Vitax’s 4.5 from 675 are the counts with saved plant texts. Two ASINs have no star line. Use the count and the subject of the texts together, and compare price per kilogram only after the weight fields agree.

Related pages

Best Epsom salt fertiliser

How to use Epsom salt fertiliser

Garden or food-grade Epsom salt

Epsom salt fertiliser

Epsom salt fertiliser for tomatoes: leaves or fruit

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the twelve amazon.co.uk listings captured on 19 October 2026. No listing here prints a magnesium oxide percentage. A shared review file is not two garden tests. This is not a laboratory test and not an RHS trial of these packs.

  1. RHS, Nutrient deficiencies (retrieved 19 October 2026)
  2. RHS, Fertilisers (retrieved 19 October 2026)
  3. RHS, Blossom end rot (retrieved 19 October 2026)
  4. GOV.UK, Manufacturing and marketing fertilisers (retrieved 19 October 2026)
  5. Regulation (EC) No 2003/2003 article 9 (retrieved 19 October 2026)
  6. Regulation (EC) No 889/2008 Annex I (retrieved 19 October 2026)
  7. Fertilisers Regulations 1991, Schedule 2 (retrieved 19 October 2026)
  8. Soil Association, organic salt clarification, 10 September 2024 (retrieved 19 October 2026)