Do slug pellet applicators need testing?
The one spreading job where the test is a legal requirement. What the law says, where your fertiliser spreader fits in, and what happens on the test.
The short answer
Yes. By law, a slug pellet applicator must pass an NSTS test before it’s five years old, then at least once every six years. Red Tractor and Scottish Quality Crops apply that to a fertiliser spreader used to apply pellets.
- The Plant Protection Products (Sustainable Use) Regulations 2012, the UK’s SUD rules, set the dates: first inspection before the fifth anniversary of purchase, then at least every six years.12
- Professional users mustn’t use equipment that hasn’t passed, and must calibrate and check it regularly.34
- Red Tractor lists “electric spinning disc and hydraulic/PTO fertiliser spreaders” as slug pelleters.5 SQC says a spreader used for pellets must be tested and calibrated for each product.6
- The NSTS test is an inspection, then a tray test to confirm working width and evenness, then an electronic report.2
- Metaldehyde has been banned outdoors in Great Britain since 1 April 2022, so most pellets now are ferric phosphate.78
What the law says
Slug pellets are a plant protection product, so the machine that spreads them falls under the Plant Protection Products (Sustainable Use) Regulations 2012: the UK’s version of the EU Sustainable Use Directive, which most people call the SUD. NSTS heads its slug pellet requirements “SUD and Assurance Scheme Requirements”.2 Regulation 12 sets the inspection dates for slug pellet applicators:1
- New equipment: inspected before the fifth anniversary of the date it was first bought.
- After that: at least once every six years.
Two more rules sit alongside. A professional user mustn’t use equipment that hasn’t passed its inspection,3 and users must calibrate and check their equipment regularly.4 The inspections are run through NSTS, which the Agricultural Engineers Association runs on HSE’s behalf.9
Does my fertiliser spreader count?
If it puts on slug pellets, the assurance schemes say yes, in so many words:
- Red Tractor (Combinable Crops and Sugar Beet, EC.7) lists “slug pelleter (including electric spinning disc and hydraulic/PTO fertiliser spreaders)”. All need an NSTS test before they’re five years old, then every six years.5
- Scottish Quality Crops says that if slug pellets go through the spreader, it must be tested and calibrated for each product.6
The regulations themselves are written for equipment designed to apply pesticides, and we haven’t found HSE guidance that names fertiliser spreaders either way. If you’re in Red Tractor or SQC, the answer is settled: test it. If you’re not, testing it is still the safe course, because it’s the same pellets going on the same land.
What happens on a slug pelleter test
NSTS lists three parts:2
- Inspection of the applicator before it spreads anything.
- A tray test to confirm the working width and how evenly the pellets land.
- An electronic report of the results, registered with NSTS.
On our tests, we count the pellets that land in each tray on both sides of the machine, then adjust the spreader until both sides match and the pattern holds across your bout width. The test also shows how far the furthest pellets are thrown, which tells you how to keep them out of field margins and watercourses.10
Why the pattern matters with pellets
Fertiliser is spread at hundreds of kilograms a hectare. Slug pellets go on at a few kilograms, so every pellet counts. Agronomists aim for at least 40 baiting points per square metre; one ferric phosphate product puts down about 59 per square metre at its full 7 kg/ha dose, according to its manufacturer.11 That’s roughly one pellet every 13 cm.
Pellets are small and light, so they don’t throw far and the wind moves them. If the spreader can’t reach the bout width you’re driving, the middle of each bout gets too few pellets to protect the crop. If one side throws further than the other, every other strip is short. And with ferric phosphate, slugs die within three to six days, often underground,7 so you won’t see the gaps as dead slugs. You’ll see them as damage.
Sprayers and granular applicators: the other dates
If you’re booking a slug pelleter test, it’s worth checking when the rest of your pesticide kit is due:
| Equipment | The law | Red Tractor and SQC |
|---|---|---|
| Boom sprayer over 3 m | Before 5 years old, then every 3 years12 | Every year for Red Tractor Crops, Fresh Produce and SQC; every 3 years for Red Tractor Beef & Lamb561314 |
| Slug pellet applicator | Before 5 years old, then every 6 years1 | Same; includes fertiliser spreaders used for pellets56 |
| Granular herbicide applicator (boom type) | Before 5 years old, then every 6 years1 | Same, and recalibrate at each change of product5 |
| Granular nematicide applicator | Before 5 years old, then every 6 years1 | Red Tractor Fresh Produce: every year13 |
Operators need the right qualification too: Red Tractor asks for an NPTC or Lantra pesticide certificate and NRoSO registration for anyone applying granular products, including slug pellets.5
Other questions people ask
Does a quad bike or ATV slug pelleter need testing?
Yes. The inspection rules cover professional pesticide application equipment other than handheld and knapsack kit,1 so a pelleter on a quad or ATV is included, and Red Tractor names electric spinning-disc spreaders in its slug pelleter row.5
How do I check when my pelleter was last tested?
Enter the test report number on the NSTS website’s lookup page. It shows when the test was registered.15
Do I need to calibrate between tests?
Yes. The regulations require users to calibrate and check equipment regularly.4 Red Tractor asks for calibration between seasons of use as a minimum, and its calibration record template says equipment applying slug pellets should be calibrated whenever the product changes.516 NSTS advises calibrating with dummy pellets of the product you’ll use.17
Is metaldehyde still allowed?
Not outdoors in Great Britain. Its sale and outdoor use have been illegal since 1 April 2022.87 Old metaldehyde stewardship rules on rates and buffer zones no longer apply; follow the label of the product you’re using.
About this article
Written by Spreadcheck (Spreader & Sprayer Testing Ltd), an NSTS testing company at Rookery Farm, Wheaton Aston, Staffordshire, which wrote the original qualification for fertiliser spreader and slug pelleter testing that NSTS adopted. We sell testing, so every figure here links to its source, and we say where the evidence is mixed.
Checked on 12 October 2026. Rules, prices and guidance change, so follow the links for the latest.
Sources
- legislation.gov.uk, The Plant Protection Products (Sustainable Use) Regulations 2012 (the UK’s “SUD” rules), regulation 12, 2012.
- NSTS, Slug pellet applicator test, accessed 2026.
- legislation.gov.uk, The Plant Protection Products (Sustainable Use) Regulations 2012, regulation 14 (use of equipment that has passed inspection), 2012.
- legislation.gov.uk, The Plant Protection Products (Sustainable Use) Regulations 2012, regulation 13 (calibration and checks), 2012.
- Red Tractor, Combinable Crops and Sugar Beet Standards, version 5.1, EC.7 and EC.10, February 2025.
- Scottish Quality Crops, The SQC Standards, 1.11, 2.17 to 2.19, October 2026.
- AHDB, Chemical and biological control of slugs, accessed 2026.
- gov.uk, Outdoor use of metaldehyde to be banned to protect wildlife, 2020.
- HSE, Bodies designated to administer equipment inspection, accessed 2026.
- Farmers Weekly, Cereals 2016: slug pellet spreaders must be tested by November, 2016.
- Farming News (manufacturer-sourced figures), Durable slug pellet critical as rain continues, 2024.
- legislation.gov.uk, The Plant Protection Products (Sustainable Use) Regulations 2012, regulation 11 (boom sprayers over 3 m), 2012, as amended.
- Red Tractor, Fresh Produce Standards, version 5.1, EC.7, February 2025.
- Red Tractor, Beef and Lamb Standards, EC.10 and guidance, 2025.
- NSTS, Look up your test details, accessed 2026.
- Red Tractor, PPP equipment calibration records template, 2021.
- NSTS, Slug pellet applicator testing leaflet, 2022.