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How to use weed killer

Updated: October 2026

The bottle is in the shed, the joints are green, and a shower is forecast. How to use weed killer starts with the label on the pack you bought, not a stronger mix or a rain rule from a different product. This page covers the seven amazon.co.uk listings in our [weed killer comparison](/hub/weed-control/weed-killer): ready-to-use sprays, a refill you pour into a pump you own, and a concentrate you dilute. It does not rank them. The Products Compared editorial team used those listings and guidance from the Health and Safety Executive and the Royal Horticultural Society on 16 October 2026. We did not run a garden trial. A qualifying purchase through our links can earn us a commission at no extra cost to you.

The bottle is in the shed, the joints are green, and a shower is forecast. How to use weed killer starts with the label on the pack you bought, not a stronger mix or a rain rule from a different product.

Our top picks

Roundup Roundup Pump 'N Go 5 litre refill

Best overall

Roundup Roundup Pump 'N Go 5 litre refill
9.3/10about £25.99
View offer
Generic Gallup 1 litre concentrate

Alternative

Generic Gallup 1 litre concentrate
8.7/10about £21.75
View offer
Roundup Roundup Total Fast Action 2 × 1 litre

Rank 3

Roundup Roundup Total Fast Action 2 × 1 litre
9.5/10about £12.98
View offer
On this page
  1. 1.Read the pack you actually bought
  2. 2.Weather and drift
  3. 3.Children, pets and the once-dry line
  4. 4.Leftovers and empty bottles

Read the pack you actually bought

Ready-to-use bottles are sprayed as sold. Roundup Total Fast Action, the 2 × 1 litre at £12.98, is for the weed only. Resolva 24H at £9.70 offers a stream or a wide angle and prints 35 square metres. The 5 litre Resolva Path & Drive pump at £25.99 is for weeds and moss, and reviewers say the pump fails, so do not tip a dead bottle into another container. The 3 litre Resolva Path & Drive at £18.00 names pelargonic acid. The Pump 'N Go 5 litre refill at £25.99 will not screw onto the sprayer. Pour it into the Pump 'N Go you already own. Reviews describe that pour, and the listing states up to three minutes once the liquid is inside. The Royal Horticultural Society says you must not store a pesticide in an unlabelled bottle, so the refill stays in its container until then. Topline Xpress 24H at £23.99 is a glyphosate-free contact refill, and a daisy bullet is not a lawn weed killer. Gallup 1 litre at £21.75 is 360 g/L glyphosate to dilute. The title says home and garden and industrial, with no MAPP number in the file, so do not assume an untrained gardener may use it. Several reviewers say the dilution slip was missing. Dilute only what you will use that day, and do not invent a rate or add extra for a large weed. Glyphosate or contact weed killer separates a root claim from a contact scorch. A further pass on a large perennial weed scorches the top and leaves the root.

Weather and drift

Spray on a warm, dry, still day, as Love The Garden repeats. Do not walk wet spray onto a lawn, and keep drift off plants you want to keep. Health and Safety Executive leaflet G212 treats those limits as typical glyphosate label warnings. It also says those labels consider rain within six hours. A Roundup path label outside this set says rain in that window may mean a repeat. None of these seven raw files prints a rain-hours line. If your label is silent, do not borrow six hours and do not strengthen the mix after a shower. Stop if spray would run into a drain, and use the weed killer for patios and driveways page for joints and pumps.
Roundup Roundup Pump 'N Go 5 litre refill

Testsieger

Roundup Roundup Pump 'N Go 5 litre refill
9.3/10about £25.99
View offer

Children, pets and the once-dry line

Only Roundup Total Fast Action 2 × 1 litre prints that children and pets may use the area once the spray is dry. The Pump 'N Go refill, the Resolva bottles, Topline and Gallup do not print that line. If your label is silent, keep children and pets off until you have that product's wording. Once dry, on that one listing, is a label sentence, not a test we ran. Wet shoes can still carry spray onto grass, and a non-selective product kills the grass it touches. In Northern Ireland a Great Britain label is not enough, because the product needs its own authorisation there. If you have hit plants you meant to keep, or the target is Japanese knotweed, call a trained person rather than washing residue into a drain.

Leftovers and empty bottles

Take unused product to a household waste recycling centre as hazardous waste. That is the HSE P501 line for amateur products, and the RHS agrees. Do not pour weed killer down a drain, a toilet or a sink, and do not tip it onto bare soil. An empty plastic container can go in household recycling, though some older labels still say the dustbin until 31 July 2028. Do not keep a diluted mix for next week. Dilute only the amount you will use that day, and if Gallup arrived with no slip, get the rate before you measure rather than guessing a capful. Pour the Pump 'N Go refill when you spray, and leave the rest in the original container. Call a trained person if the pack is professional and you are not, or if a drive cannot be treated without run-off to a drain.

Common questions

When should I spray?
Spray on a warm, dry, still day. Do not walk wet spray onto a lawn. None of these seven listings prints a rain-hours figure. HSE notes say labels consider rain within six hours, and another Roundup path label says that window may mean a repeat. If the label is silent, do not copy it.
Can I mix it stronger if the weeds are large?
Do not strengthen a mix because a dock looks large. The Health and Safety Executive forbids that extra. A contact spray such as Topline may need a second treatment on a large perennial weed. The second pass scorches the top and does not kill the root. On Gallup, dilute only the day's amount at the printed rate.
What if the Gallup bottle has no dilution note?
Stop before you measure. Gallup 1 litre is 360 g/L glyphosate, and several reviewers say the slip was missing. The raw file has no millilitre figure. The title says home and garden and industrial, with no MAPP number. Check the HSE garden product search before you treat it as an amateur bottle.
How do I use a refill that will not screw onto the pump?
Pour it into the Pump 'N Go you already own. The Roundup 5 litre refill at £25.99 does not swap its cap, and reviews describe pouring rather than screwing. The listing states up to three minutes once the liquid is in the pump. Leave the rest in the original container. The RHS says decanting a pesticide into an unlabelled bottle is illegal.
How long until children and pets can use the area?
Only Roundup Total Fast Action 2 × 1 litre says children and pets may return once the spray is dry. The refill, Resolva, Topline and Gallup do not print that sentence. If your label is silent, keep children and pets off until you have its wording. A dry leaf on another product is not the same permission.
Where do I take leftover product?
Take unused weed killer to a household waste recycling centre as hazardous waste. That is the HSE P501 line for amateur products, and the RHS names the same place. Do not pour it down a drain, a toilet or a sink, or onto bare soil. An empty plastic bottle can go in household recycling. Some older labels still say the dustbin until 31 July 2028.
Can I keep a jug of diluted spray for next week?
Do not store a diluted mix until next week. The RHS says not to keep a made-up solution, and a concentrate is only for the amount you use that day. A jug is an unlabelled container, which must not hold a pesticide. Pour a refill into the Pump 'N Go when you spray, and leave the rest in the product container.

Related pages

Weed killer buying guide

Weed killer

Best weed killer for joints, a drive or a bed edge

Glyphosate or contact weed killer: root claim or scorch

Weed killer for patio and driveway: moss and drains

Sources

Public UK sources from the research digest, last checked on 16 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the display file. This page did not run a laboratory test and does not confirm a MAPP number.

  1. HSE: garden and allotment use (retrieved 16 October 2026)
  2. HSE: glyphosate renewal (retrieved 16 October 2026)
  3. HSE: garden pesticide search (retrieved 16 October 2026)
  4. HSE: G212 contact and glyphosate (retrieved 16 October 2026)
  5. HSE: P501 amateur disposal (retrieved 16 October 2026)
  6. RHS: weeds on hard surfaces (retrieved 16 October 2026)
  7. RHS: storing and disposing of chemicals (retrieved 16 October 2026)
  8. DAERA: operator responsibilities for pesticides (retrieved 16 October 2026)