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How to apply iron fertiliser from the bottle label

Updated: October 2026

The useful question is how to apply iron fertiliser without copying a number that was never a dilution. Several amazon.co.uk mixing fields in this comparison say 1, 1:0:0 or 1:20. Those are not recipes. This page is about scorch, stain and pets once you hold a product. The shelf is on the [iron fertiliser comparison](/hub/fertiliser-soil-and-bark-mulch/iron-fertiliser). If you are unsure of the form, use the [iron fertiliser buying guide](/hub/fertiliser-soil-and-bark-mulch/iron-fertiliser/sub/iron-fertiliser-buying-guide) first. Peter F., the DIY and tools editor, updated this on 21 October 2026 from the sheets named below and the listings. This is not a garden trial. A qualifying purchase can earn a commission at no extra cost to you.

The useful question is how to apply iron fertiliser without copying a number that was never a dilution. Several amazon.co.uk mixing fields in this comparison say 1, 1:0:0 or 1:20. Those are not recipes.

Our top picks

Doff Doff Sequestered Iron Plant Tonic

Best overall

Doff Doff Sequestered Iron Plant Tonic
7.3/10about £5.99
View offer
Maxicrop Maxicrop Sequestered Iron 500 ml

Rank 2

Maxicrop Maxicrop Sequestered Iron 500 ml
8.9/10about £7.14
View offer
Pro-Kleen Pro-Kleen Iron Sulphate 2.5 kg

Alternative

Pro-Kleen Pro-Kleen Iron Sulphate 2.5 kg
6.6/10about £16.95
View offer
On this page
  1. 1.Read the bottle you are holding
  2. 2.Sequestered iron in the watering can
  3. 3.Lawn granules, without a soluble recipe
  4. 4.Stain, scorch and pets
  5. 5.Aquarium and hydroponic bottles

Read the bottle you are holding

On the Maxicrop 500 ml listing the mixing field is the digit 1. On the Doff powder and the Maxicrop twin pack it is 1:0:0. Easy-Life Ferro prints 1:20 and a bullet of 5 ml per 100 litres, and those figures do not match. The Maxicrop professional sheet gives a shrub mix and a lawn mix for that liquid. Sunshine prints 1:400 on the 5 litre title. If the carton differs, follow the carton.

Sequestered iron in the watering can

For ericaceous shrubs, the Maxicrop professional sheet states 45 ml in 9 litres, as a root drench or a foliar spray, every 14 days as required. A footnote treats that as 1 part to 200. That line is not the amazon field. The same sheet gives 40 ml in 4.5 litres per 10 m² for lawns, two or three times a year. Do not dissolve Pro-Kleen granules to match it. Skip frost, heavy rain, extreme heat and drought. The Doff website says one 15 g sachet in 4.5 litres and says to avoid foliage. Do not copy that onto Maxicrop.
Doff Doff Sequestered Iron Plant Tonic

Testsieger

Doff Doff Sequestered Iron Plant Tonic
7.3/10about £5.99
View offer

Lawn granules, without a soluble recipe

Pro-Kleen is ready-to-use granules, 2.5 kg, up to 83 m², with no mixing. Do not use a soluble sheet, or a 25–35 g/m² figure from another Pro-Kleen page, as the rate for this tub. Do not average 83 m² with up to 100 m², and do not replace up to three months if there is no frost with another interval. Spread on the grass, not on the patio. Do not use it if frost is likely. The listing does not add a summer ban.

Stain, scorch and pets

Pro-Kleen says it may stain hard outdoor surfaces. Brush or blow dry granules off paving while they are still dry. Keep a liquid iron mix on the soil. Scorch is more likely if you overdose, apply in extreme heat or drought, or wet foliage the label told you to avoid. Keep pets and children off while it is wet. Iron salts are harmful if eaten. Fertiliser-only ferrous sulphate is not a moss killer unless it is HSE-authorised. The leaf pattern is on yellow leaves and iron deficiency.

Aquarium and hydroponic bottles

Easy-Life’s UK page states 5 ml per 100 litres, weekly. Use that, not a shop page that says 10 ml, and not the amazon field of 1:20. A 100 litre tank takes one 5 ml measure into the water, not a watering can on the border. CANNA Mono FE has no numeric garden dose. Stable with each pH is not a named chelate and not a shrub rate. If the bottle is CANNA or Easy-Life and the plant is a rhododendron, go back to the buying guide. Lawn versus shrub iron is linked below.

Common questions

How do I dilute Maxicrop if the amazon field only says 1?
Do not dilute from the digit 1. The Maxicrop professional sheet, which is not the amazon field, states 45 ml in 9 litres for ericaceous shrubs, every 14 days as required, as a drench or a foliar spray. The same sheet states 40 ml in 4.5 litres per 10 m² for lawns, two or three times a year. If your label prints a different rate, follow the label.
How do I put the Pro-Kleen granules on the grass?
Spread them dry. The listing says there is no mixing, and coverage is up to 83 m² for 2.5 kg. Do not dissolve them using a blog rate from a different product. Keep granules off paving, and do not apply if frost is likely. The listing interval is up to three months if there is no frost.
Will ferrous sulphate stain paving?
Yes. The Pro-Kleen listing warns about hard outdoor surfaces. Brush or blow dry granules off the slabs before they get wet. Do not assume a hose will lift a stain that has already formed. Keep liquid iron on the soil as well. If the patio is the only place you can stand, this tub is a poor match.
When can pets and children use the lawn again?
Keep them off while the treatment is wet. This page does not borrow a 24-hour or a three-day interval from another seller. Iron salts are harmful if eaten, and the Maxicrop sheet says to store concentrate out of reach of children and pets. If granules or liquid have been swallowed, seek urgent help.
Can I spray sequestered iron onto open flowers?
The Maxicrop professional sheet allows a foliar spray as well as a root drench. The Doff website, for the powder, says to avoid foliage and to stop before flowering so you do not stain petals and fruit. Those are two products. Read the one you hold. If flowers are open and the label is silent, drench the soil.
Is a hot day or a frost a reason to wait?
Yes. The Maxicrop sheet avoids frost, heavy rain, drying winds, extreme heat and extreme drought for that liquid. The Pro-Kleen listing says not to use the granules if frost is likely. Wait for a milder day and for soil that is not baked.

Related pages

Iron sulphate or sequestered iron

Iron fertiliser

Best sequestered iron in the UK for a named garden job

Iron fertiliser buying guide: choose the right form

Yellow leaves and iron deficiency on youngest growth

Sources

Public UK and maker sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the ten amazon.co.uk listings. A Soil Association line is an organic-growing claim, not a pet study. The Maxicrop 2% and 45 ml figures are from the professional sheet, not from the amazon mixing field. Chelate pH bands from a US extension summary are not UK law.

  1. RHS, nutrient deficiencies (retrieved October 2026)
  2. RHS, chalky soils (retrieved October 2026)
  3. RHS, moss in lawns (retrieved October 2026)
  4. GOV.UK, manufacturing and marketing fertilisers (retrieved October 2026)
  5. legislation.gov.uk, Regulation (EC) No 2003/2003, Article 9 (retrieved October 2026)
  6. HSE, garden and home pesticides (retrieved October 2026)
  7. Maxicrop professional iron sheet (retrieved October 2026)
  8. Easy-Life Ferro (retrieved October 2026)