Key takeaways
- Home-made mixes aren't legal to use as pesticides in the UK, even on your own plants
- Only authorised products, used as the label says, may be used to kill or deter pests
- Squashing, hosing off and hand-picking deal with most small outbreaks
- Netting, fleece, collars and traps stop pests reaching crops
- Ladybirds, hoverflies, birds and bought-in biological controls do the rest
- Look for a MAPP number and 'amateur use' on any spray you buy
Aphids all over the roses and a bottle of washing-up liquid by the sink: it’s tempting. But home-made pest sprays aren’t legal to use in the UK, and there are easier ways to keep pests down anyway. Squashing, hosing, netting, traps and helpful bugs sort out most problems. When a spray really is needed, buy an authorised one and follow the label.
This guide explains the rules in plain words, then walks through eight simple methods that work. For a pest-by-pest look at chemical-free control, see the organic pest control guide.
Are home-made pest sprays allowed in the UK?
Not as pest killers. Anything you use to kill or deter pests, weeds or plant diseases has to be an authorised garden product, used the way its label says. That rules out soapy water, garlic, chilli and vinegar mixes, even on your own plants.
Squashing, hosing, netting, traps and nematodes are all fine. If you do buy a spray, look for “amateur use” and a MAPP number on the label. That number shows it’s authorised. The HSE pesticides pages have the full rules if you want them.
Squash and hand-pick pests
Your fingers are the cheapest pest control there is. Rub out aphid colonies between finger and thumb, wearing gloves if you prefer. Pick caterpillars and their egg clusters off brassica leaves. Knock lily beetles, rosemary beetles and vine weevil adults into a tray held under the plant.
Collect slugs and snails by torchlight on damp evenings, when they’re out feeding. Check plants every few days from April, so colonies never get the chance to build up. The guide to getting rid of aphids has more tips for greenfly and blackfly.
An evening slug patrol with a torch and a jar does more than any barrier. Damp nights are the best time to go hunting.
Hose pests off with water
A firm jet of plain water knocks aphids, whitefly and spider mite off plants. Most never climb back. Aim at the undersides of leaves and the soft shoot tips, where colonies live, and repeat every few days.
A sharp blast of plain water knocks greenfly off, and most never make it back. Repeat every few days.
In a greenhouse, damping down the floor on hot days raises the humidity, which red spider mite dislikes. Plain water is fine to use however you like. It’s only once you add soap or other ingredients to kill pests that it becomes a pesticide.
Netting, fleece and mesh
Fine insect mesh keeps pests off without any spray. It stops cabbage white butterflies, carrot root fly, flea beetle and leek moth reaching your crops. Butterfly netting over brassicas stops caterpillar damage before it starts.
A fleece or mesh barrier about 60cm tall around carrots keeps carrot root fly off, as the flies travel low. Secure the edges with bricks or pegs, because pests find any gap.
Fine mesh keeps butterflies, flea beetles and root flies off with no spray at all. Weigh down the edges so nothing sneaks in.
Collars, barriers and traps
Collars around transplants protect them from cabbage root fly and cutworms. Fit a card or rubber collar snugly round the stem when you plant out.
Card collars stop cabbage root fly laying eggs at the stem, and a sunken beer trap catches slugs overnight.
Slug barriers are less reliable. Copper tape, wool pellets, grit and eggshells do little to stop slugs, so hand-picking is the better bet. A beer trap helps: sink a yoghurt pot to soil level and part-fill it with cheap beer. Upturned grapefruit halves or boards on the soil give slugs somewhere to hide by day, so you can collect them. The guide to getting rid of slugs covers more options.
Yellow sticky traps in the greenhouse catch some whitefly and help you spot a problem early.
Encourage predators to do the work
Ladybirds, hoverflies, lacewings, ground beetles, frogs, hedgehogs and birds eat huge numbers of pests. Make them welcome and they’ll do much of the work for you.
A ladybird larva can munch through a whole aphid colony. Hold off spraying and let the helpers move in.
Plant open flowers such as calendula, yarrow and fennel. Leave a log pile, add a small pond and avoid spraying anything while predator numbers build. Aphid colonies that appear in late spring are often cleared by predators within a few weeks if you’re patient.
Buy in biological controls
Biological controls are legal, specific and safe around people and pets. They’re living predators or parasites that target one pest.
Slug nematodes go on with a watering can in mild, damp weather. They’re safe around pets and other wildlife.
- Slug nematodes, watered into moist, warm soil, attack slugs underground.
- Vine weevil nematodes tackle the grubs in pots.
- Encarsia formosa, a tiny wasp, controls greenhouse whitefly.
- Phytoseiulus persimilis, a predatory mite, eats red spider mite.
The guide to biological pest control covers timing and soil temperatures. For problems under glass, the organic greenhouse pest control plan shows how to use them through the season.
Hygiene, pruning and tougher plants
Healthy, well-spaced plants get fewer pest problems. Prune out badly infested shoot tips and clear fallen fruit and diseased leaves. Space plants for good airflow.
Feed with restraint, as soft, sappy, overfed growth attracts aphids. Choose resistant varieties where they exist, and rotate vegetable crops each year so pests in the soil don’t build up.
Home-made mixes to skip
These turn up online a lot. Give them a miss:
- Soap or washing-up liquid mixes can scorch leaves and harm ladybirds and other helpful insects.
- Garlic and chilli mixes sting eyes and skin, and aren’t approved for pests.
- Neem oil sold as leaf shine or pet care oil isn’t approved for pest control. The guide to neem oil in UK gardens explains why.
- Bleach and salt damage the soil for a long time.
- Vinegar scorches any plant it touches. For weeds, the guide to organic weedkillers covers legal options.
- Petrol, paraffin or WD-40 are toxic and a fire risk.
- Mothballs aren’t for garden use.
What to do instead: a quick guide
| Problem | Best response |
|---|---|
| Small aphid colony | Squash or hose off, repeat every few days |
| Whitefly in the greenhouse | Yellow sticky traps to spot it, then Encarsia |
| Caterpillars on brassicas | Hand-pick, then net the crop |
| Slugs on hostas or lettuce | Torchlight patrols, beer traps, nematodes or authorised ferric phosphate pellets |
| Scale insects on indoor plants | Scrape off with a fingernail or soft brush |
| Red spider mite under glass | Damp down and release Phytoseiulus |
| Carrot root fly | Fleece or mesh barrier, no spray needed |
| Aphids everywhere | Let predators catch up; authorised product only if crops are at real risk |
Common mistakes with pest control
- Reaching for a spray first. Most outbreaks are small and short-lived. Squashing, hosing and patience let predators catch up.
- Mixing up a home-made remedy. It isn’t legal, and it can scorch plants and kill the predators that would have solved the problem.
- Targeting the wrong pest. Identify the pest first. A hose does nothing for caterpillars, and netting does nothing for slugs.
- Ignoring the label. An authorised product is only legal on the plants, pests and doses its label lists.
- Spraying open flowers. Even authorised products can harm bees. Follow the label and keep sprays off flowers that pollinators visit.
Month-by-month pest control calendar
| Month | What to do |
|---|---|
| January | Order nematodes and biological controls for spring |
| February | Check netting and fleece; repair holes |
| March | Check indoor seedlings for aphids and squash any colonies |
| April | Net brassicas and fleece carrots before pests arrive |
| May | Squash or hose off rose aphids. Fit collars on transplants |
| June | Watch for greenhouse whitefly and spider mite; release biological controls |
| July | Check plants often. Hand-pick caterpillars and eggs |
| August | Evening slug patrols around late salad crops |
| September | Check houseplants for scale and mealybug before bringing them in |
| October | Clear fallen leaves and fruit |
| November | Plan next year’s netting and prevention |
| December | Note what worked. Order seed of resistant varieties |
Frequently asked questions
Are homemade pesticides legal in the UK?
No, home-made mixes aren’t legal to use as pesticides. Anything used to kill or deter pests, diseases or weeds must be an authorised product. That applies on your own plants too. Hand methods, barriers and biological controls are all fine.
What is the best homemade pesticide for aphids?
There isn’t a legal one, but you don’t need it. Squash small colonies, blast them off with a jet of water and let ladybirds and hoverfly larvae clear the rest. For a heavy outbreak, use an authorised insecticide exactly as the label says.
Does garlic spray actually work as a pesticide?
It doesn’t matter, because it isn’t legal to use as one. Home-made garlic spray isn’t an authorised product. Netting brassicas and picking off caterpillars and eggs protects crops far more reliably.
Can I use neem oil legally in the UK?
Not to kill or deter pests, unless the product is authorised for that. Neem oil sold as a leaf shine, cosmetic or pet care oil isn’t authorised, so spraying it on pests isn’t legal.
What homemade recipes should I avoid?
Skip any home-made mix meant to kill pests or weeds. Soap, garlic, chilli, vinegar, salt and bleach mixes aren’t approved, and some harm soil and wildlife. Try hand-picking, netting and traps first.
How do I know if a garden spray is authorised?
Look for a MAPP number on the label. Authorised garden products also say they’re for amateur or home garden use. Use them only on the plants and pests the label lists.
Find more pest fixes in the pest control hub. To bring in the predators that do the work for you, read our companion planting guide next.
Our team produces practical UK gardening guidance from source research, contributor records and established horticultural practice. Editorial standards are overseen by Matt W.
