Complete Greenhouse Pest Control Guide UK
How to identify, prevent, and treat common greenhouse pests using natural methods that work in UK conditions
Key Takeaways
- UK greenhouses have unique pest problems because our mild, damp weather creates perfect breeding conditions.
- Prevention works better than treatment - basic cleanliness and good habits stop most problems.
- Natural pest control is safer for food crops and your family.
- Check plants weekly during growing season - spot problems early and save yourself hours of work.
- Different pests appear at different times - know when to expect them so you can be ready.

One aphid can have 80 babies in a week. In your warm greenhouse, that means 6,000+ aphids in a month if you don't catch them early. For UK gardeners, pest control isn't just about plant health—it's about protecting months of work from bugs that love our mild climate.
UK greenhouses are different from outdoor gardening. Outside, cold winters kill most pests and natural predators control the rest. Inside your greenhouse? It's warm, sheltered, and full of food. Perfect conditions for pests.
The RHS says UK gardeners lose over £500 million worth of crops each year to greenhouse pests. Most of these losses could be prevented.
I'll show you exactly how to identify the common troublemakers, stop them before they start, and deal with them naturally if they get in. No harsh chemicals, no complicated procedures—just practical methods that work in real UK conditions.
Common UK Greenhouse Pests: What You're Dealing With
Most UK greenhouse pests are predictable. The trick is catching them early—before they multiply.
Quick Pest Identification Reference
Pest | Size | Appearance | Location on Plant | Damage Signs | Peak Season |
---|---|---|---|---|---|
Aphids (Green) | 2-4mm | Pear-shaped, green, soft body | New growth, flower buds | Yellow/curled leaves, sticky honeydew | April-June |
Aphids (Black) | 2-4mm | Pear-shaped, black, soft body | Young shoots, leaf undersides | Yellow/curled leaves, sticky honeydew | April-June |
Whitefly | 1-2mm | White, moth-like, flies in clouds | Leaf undersides (larvae) | Yellow leaves, sticky honeydew, stunted growth | May-September |
Red Spider Mites | 0.5mm | Nearly invisible, red/brown | Leaf undersides | Fine webbing, yellow stippling on leaves | June-August |
Slugs | 2-3cm | Grey/brown, slimy | Ground level, under staging | Irregular holes, slime trails | Year-round |
Vine Weevil (Adult) | 9mm | Dark grey-black beetle | Leaf edges (night feeding) | Notched leaf edges | April-October |
Vine Weevil (Larvae) | 8-10mm | White, C-shaped grubs | Soil/compost | Sudden plant collapse, root damage | Year-round |
Caterpillars | 2-4cm | Green, segmented body | Leaves, stems | Clean holes, severed stems | April-May, July-August |
Fungus Gnats | 2-3mm | Dark flies around soil | Compost surface | Hovering flies, larvae in soil | October-March |

Sap Suckers (They Drain Your Plants)
Aphids - Green and Black Bugs
You've probably seen these. Tiny, soft green or black bugs that cluster on new shoots. In the UK, we mainly get green peach aphids and black bean aphids—both about 2-4mm long.
How to spot them: pear-shaped with long antennae and two little tubes sticking out their back. They hang out on the youngest, tenderest growth—new leaves, flower buds, anywhere the plant sap flows easily.
You'll know you have them because leaves turn yellow and curly, and there's sticky stuff (honeydew) all over everything. Sometimes this sticky mess gets black mould on top.
In UK greenhouses, aphids really get going in spring (April-June) when heating keeps things warm. They breed fast in warm conditions.

Whitefly - Tiny White Flying Insects
Easy to spot. Touch an infected plant and clouds of tiny white flying insects appear—they look like mini moths, about 1-2mm long. The adults aren't the main problem. Their larvae—tiny, clear, scale-like things stuck under leaves—do most damage.
Whitefly damage looks like aphid damage: yellow leaves, stunted growth, sticky honeydew. They love tomatoes, cucumbers, and fuchsias.
In UK greenhouses, outdoor populations die in winter but your heated greenhouse keeps them going year-round. One female lays 400 eggs and they go from egg to adult in 3-4 weeks when warm. That's a lot of whiteflies quickly.

Red Spider Mites - Nearly Invisible Plant Suckers
These are sneaky. At 0.5mm long, you need a magnifying glass to see them. But their damage is obvious: tiny yellow or white spots on leaves where they've sucked out sap, then leaves go bronze and drop off.
The giveaway is fine webbing on leaves and stems. Bad infestations can cover whole plants in webbing.
Red spider mites love hot, dry conditions—exactly what many greenhouse crops prefer. They're worst during summer when ventilation can't keep up with heat and humidity drops.

Chompers (They Eat Everything)
Slugs and Snails - Night Feeders
Garden slugs are bad enough, but greenhouse ones never stop for winter. They get in through door gaps, vents, and on new plants. Once in, they love the consistently moist conditions.
Greenhouse slugs are usually smaller than outdoor ones—about 2-3cm—but they're hungry. You'll see irregular holes in leaves, destroyed seedlings, and silver slime trails on staging and pots.
Because your greenhouse stays warm, they're active all year. They hide during the day under staging, in drainage holes, and under plant debris, then feed at night.

Caterpillars - Fast Destroyers
Several UK moths use your greenhouse as a nursery. Most common are cabbage moth caterpillars (green, up to 4cm long) and cutworms that cut seedlings at ground level.
Caterpillar damage happens fast—clean holes in leaves, cut stems, sometimes whole plants stripped overnight. Unlike aphids that gradually weaken plants, caterpillars can destroy crops while you sleep.
UK greenhouse caterpillars usually appear twice yearly: spring from pupae that survived winter, and summer when adult moths fly in through vents to lay eggs.
Underground Attackers (Root Destroyers)
Vine Weevil - Double Trouble
This might be your worst pest. Adult vine weevils are dark grey-black beetles about 9mm long that nibble notches around leaf edges. But their larvae—fat, white, C-shaped grubs—destroy root systems.
Above ground: notched feeding marks on leaves. Below ground: grubs quietly destroying roots, so plants suddenly collapse even though they looked fine yesterday. Container plants are especially vulnerable.
Vine weevils are tricky because adults hide during the day and only come out at night, while larvae stay hidden in compost for months. By the time you see plant damage, root destruction is often too severe to fix.
Fungus Gnats - Overwatering Indicators
These tiny flies (2-3mm) look like fruit flies but they're actually telling you about your watering habits. If you have fungus gnats, you're probably overwatering.
Adult flies are just annoying, but their larvae live in soggy compost and eat organic matter and fine roots. They're particularly damaging to seedlings and young plants.
You'll see them hovering around plant bases and compost surfaces, especially after watering. They're most common in winter when reduced light and cooler temperatures keep compost wet longer.
Natural Pest Control That Works
Natural pest control often works better than chemicals, lasts longer, and won't harm you, your family, or beneficial insects. Plus, if you're growing food, you don't want chemicals on your dinner.
Natural Treatment Quick Reference Guide
Pest Problem | First Choice Treatment | Application Method | Frequency | When to Use |
---|---|---|---|---|
Few Aphids | Soap spray | Spray all surfaces, focus on undersides | Every 3-5 days | As soon as spotted |
Many Aphids | Ladybirds + Neem oil | Release beneficials, spray weekly | Release once, spray weekly | When >10 per plant |
Whitefly | Encarsia wasps | Release near affected plants | Every 2-3 weeks | Early in season |
Red Spider Mites | Phytoseiulus mites | Release on affected plants | Once (they establish) | When webbing appears |
Slugs | Copper tape + traps | Apply around pots/staging | Tape lasts years | Year-round prevention |
Vine Weevil Adults | Nematodes (soil) | Water into compost | Once per year | April-May, August-September |
Caterpillars | Hand picking + Bt spray | Remove by hand, spray if severe | Daily picking, spray weekly | As soon as spotted |
Fungus Gnats | Reduce watering + yellow traps | Allow soil to dry, position traps | Ongoing | When flies appear |
Get Nature to Do the Work
Beneficial Insects - Your Bug Army
You can buy good bugs that eat bad bugs. It's like hiring pest control that works for food instead of money.
Beneficial Insect Release Planner
Beneficial Insect | Target Pest | Best Release Time | Temperature Needed | How Many to Release | Where to Buy |
---|---|---|---|---|---|
Ladybirds | Aphids | April-May | 15°C+ | 50-100 per greenhouse | Garden centres, Defenders |
Encarsia Wasps | Whitefly | April-June | 18°C+ | 3-5 per m² | Dragonfli, Biological Services |
Phytoseiulus Mites | Red Spider Mites | May-August | 18°C+ | 2-5 per plant | Specialist suppliers |
Lacewing | Aphids, Thrips | April-September | 15°C+ | 1000 eggs per greenhouse | Online suppliers |
Predatory Mites | Soil pests | March-October | 12°C+ | 50-100 per m² | Specialist suppliers |
Ladybirds are stars here. One ladybird eats 5,000 aphids in its lifetime, and their larvae are even hungrier. UK-bred ladybirds adapt well to greenhouse conditions and often stay permanently.

For whitefly, get Encarsia wasps. Don't worry—they're tiny parasitic wasps (0.6mm) that couldn't sting you if they tried. They lay eggs inside whitefly larvae, killing them before they reproduce. Use them early before whitefly populations explode.
Red spider mites get controlled by Phytoseiulus mites—predatory mites that move faster than spider mites and eat 20 per day. They thrive in slightly humid conditions that UK greenhouses naturally maintain.
UK suppliers like Defenders, Dragonfli, and Biological Services sell these with proper instructions. Most work best when greenhouse temperatures stay 18-25°C—easy in UK conditions.
Companion Planting - Strategic Plant Placement
Some plants naturally repel pests or attract beneficial insects.
Companion Planting Quick Guide
Companion Plant | Repels | Plant With | Spacing | Additional Benefits |
---|---|---|---|---|
French Marigolds | Aphids, Whitefly | Tomatoes, Peppers | 30cm apart | Edible flowers |
Basil | Aphids, Flies | Tomatoes | 20cm from plants | Fresh herbs |
Nasturtiums | Aphids (trap crop) | Cucumbers | Edge of beds | Edible leaves/flowers |
Chives | Aphids | Anywhere | 15cm apart | Culinary use |
Mint | Ants, Mice | In pots only | Contained | Culinary/tea use |
Lavender | Many flying insects | Near doorways | 40cm apart | Fragrance |
Marigolds release compounds that deter aphids, whiteflies, and soil pests. French marigolds work particularly well, and compact varieties fit easily around larger crops.
Plant basil near tomatoes for two benefits: aromatic oils repel aphids and flying insects, plus you get fresh herbs. Both plants like similar conditions.
Nasturtiums work as trap crops—aphids prefer them to most other plants, so they attack nasturtiums first, giving you time to spot problems.

Physical Barriers
Sticky Yellow Traps - Early Warning System
Most flying greenhouse pests are attracted to yellow, so yellow sticky traps work for monitoring and population control.
In a standard 8x6 foot greenhouse, use 4-6 traps at plant height throughout the space. Focus on vents where pests typically enter. Replace when 80% covered or monthly during growing season.
UK tip: keep using traps through winter in heated greenhouses. Mild winter periods can activate overwintering pests.
More than 10-15 flying insects per trap per week means you might need stronger control measures.

Copper Tape - Slug Stopper
Copper tape creates a mild electrical charge when slug slime touches it. It's one of the most reliable slug deterrents.
Apply copper tape around pot rims, staging legs, and door frames. It needs to be at least 2cm wide—narrower strips can be bridged by determined slugs.
UK suppliers now offer greenhouse-specific copper tape that won't tarnish in humid conditions. While it costs more upfront than slug pellets, it lasts years.

Fine Mesh - Pest Exclusion
Install 0.6mm mesh over vents to keep flying pests out while maintaining airflow. This size excludes most greenhouse pests while allowing adequate ventilation.
Focus on roof vents and lower wall vents where pests typically enter. Don't screen everything—you need some unscreened vents for maximum airflow during hot weather.
Organic Sprays
Neem Oil - Multi-Purpose Natural Pesticide
Neem oil comes from the Indian neem tree and works differently from chemical pesticides. Instead of killing pests instantly, it disrupts their feeding and reproduction, making it safer for beneficial insects and food crops.
UK-approved products like Neudorff or SB Plant Invigorator work against aphids, whiteflies, and other soft-bodied pests. Apply during cooler parts of the day (early morning or evening) to prevent leaf scorch.
Mix according to instructions—usually 5-10ml per litre water—and spray all plant surfaces. Repeat every 7-14 days during infestations, reducing frequency as pest numbers drop.
Neem oil works well in UK greenhouse conditions because it stays effective at lower temperatures than many other organic treatments.

Soap Spray - Simple and Safe
Basic soap spray kills soft-bodied pests immediately while being completely safe for food crops. Use proper soap though—not washing-up liquid with additives that might harm plants.
Mix 5ml of pure castile soap or horticultural soap per litre water. In hard water areas, add a pinch of bicarbonate of soda. Spray thoroughly, hitting leaf undersides where pests hide.
Soap works by disrupting pest cell membranes, so it only affects pests it touches directly. You need thorough coverage and repeat treatments every 3-5 days during infestations.
UK suppliers like Vitax and West Riding Organics offer ready-mixed organic soap sprays.
Diatomaceous Earth - Natural Pest Powder
Food-grade diatomaceous earth is made from fossilised algae and works mechanically. It damages soft-bodied insects' protective coating, causing dehydration.
Dust lightly around plant bases, on staging surfaces, and anywhere crawling pests travel. Reapply after watering or high humidity periods.
Works best during drier periods in well-ventilated areas. Particularly effective around staging bases and corners where pests shelter during the day.
Buy food-grade diatomaceous earth from UK suppliers like Dragonfli—avoid pool-grade products with harmful additives.
Prevention: Stop Problems Before They Start
Prevention is ten times easier than treatment. Get prevention right and you'll rarely need to worry about serious pest problems.
Keep It Clean
Annual Deep Clean - February Fresh Start
Time your annual greenhouse clean for late winter (February-March) to eliminate overwintering pests before they wake up and start breeding.
Empty everything—plants, pots, staging, tools. Brush down all surfaces to remove debris, cobwebs, and pest hiding spots. Pay attention to crevices around doors, vents, and staging where pests commonly spend winter.
Wash everything with 1 part household bleach to 10 parts water, or use specialised greenhouse disinfectants. This kills pest eggs, fungal spores, and bacteria without harmful residues.
Let everything dry completely before putting it back—usually 24-48 hours in UK conditions.

Quarantine New Plants - Two-Week Rule
New plants are the biggest risk for bringing pests into your clean greenhouse. Proper quarantine prevents most pest introductions.
Set up a quarantine area away from your main greenhouse—small cold frame, spare greenhouse section, or bright indoor spot. Keep new plants isolated for at least 14 days, checking them every 2-3 days.
Look for sticky honeydew, unusual leaf damage, tiny insects, or root problems. Check leaf undersides, growing tips, and soil surfaces.
UK garden centres vary hugely in pest management. Specialist nurseries usually have cleaner stock than general retailers, but quarantine everything.
Clean Tools Between Jobs
Tools can transfer pest eggs and diseases between plants faster than you think.
Keep a container of diluted bleach solution (1:10 ratio) or methylated spirits near your working area. Dip tools between uses, especially when moving between different plant types.
Pay extra attention when working with plants showing pest or disease signs.
Replace sterilisation solution weekly during busy periods.
Control the Environment
Humidity Management
Most UK greenhouse pests thrive in specific humidity ranges. Get this right and you create conditions that support plants while discouraging pests.
Aim for 50-70% humidity for most crops during growing season. This keeps plants happy while being too dry for many fungal problems and slightly low for optimal red spider mite breeding.
Use digital hygrometers at plant level throughout your greenhouse. UK conditions often see big humidity swings between day and night.
Reduce morning humidity spikes through strategic ventilation, especially during early morning when overnight condensation increases moisture. Automatic vent openers help maintain consistent conditions.
Small fans positioned for gentle air movement prevent stagnant conditions that encourage pests while naturally moderating humidity.
Temperature Control
Consistent temperature management disrupts pest breeding cycles while supporting optimal plant growth. Most pests need specific temperature ranges for successful reproduction.
Maintain 18-25°C during the day for most crops, dropping 3-5°C at night. This natural temperature cycle stresses many pests while supporting plants.
Avoid temperature spikes above 30°C, which stress plants and make them more vulnerable to pest attack. This often requires active summer cooling through increased ventilation or shading.
Use thermal screens or insulation during cold periods to maintain minimum temperatures without creating hot spots that some pests prefer.
Monitor temperature variations throughout your greenhouse using min-max thermometers at different locations.
Month-by-Month Pest Prevention Calendar
Different pests become active at different times. Know when to expect them and you can be ready.
Monthly Pest Activity Calendar
Month | High Risk Pests | Medium Risk Pests | Low Risk Pests | Key Actions |
---|---|---|---|---|
January | Fungus Gnats | Slugs, Vine Weevil | - | Monitor traps, plan spring cleaning |
February | Fungus Gnats | Slugs, Vine Weevil | - | Deep clean, service equipment |
March | Slugs, Vine Weevil | Aphids | - | Set up monitoring, seal gaps |
April | Aphids, Vine Weevil | Whitefly, Slugs | Red Spider Mites | Release beneficial insects, increase monitoring |
May | Aphids, Whitefly | Red Spider Mites, Caterpillars | Slugs | Daily monitoring, organic sprays if needed |
June | Whitefly, Red Spider Mites | Aphids, Caterpillars | Vine Weevil | Peak monitoring, environmental controls |
July | Red Spider Mites, Whitefly | Caterpillars, Aphids | - | Heat management, continue controls |
August | Red Spider Mites, Whitefly | Caterpillars, Vine Weevil | - | Sustained monitoring, harvest regularly |
September | Vine Weevil, Aphids | Whitefly, Red Spider Mites | Slugs | Begin autumn cleanup |
October | Vine Weevil, Slugs | Aphids | - | Winter prep, final treatments |
November | Slugs, Vine Weevil | - | Fungus Gnats | Complete winter prep |
December | Fungus Gnats | Slugs, Vine Weevil | - | Minimal monitoring, planning |
Seasonal Task Checklist
Spring Tasks (March-May)
- March: Complete annual deep clean
- March: Check and seal structural gaps
- March: Set up sticky trap monitoring system
- March: Service heating and ventilation systems
- April: Increase monitoring to twice weekly
- April: Order beneficial insects for May release
- April: Plant companion plants (marigolds, basil)
- May: Switch to daily monitoring
- May: Apply first organic treatments if needed
- May: Release beneficial insects
Summer Tasks (June-August)
- June: Daily pest monitoring during peak season
- June: Install shading to prevent heat stress
- June: Begin weekly spray rotations if needed
- July: Monitor temperature/humidity closely
- July: Increase watering frequency (but ensure drainage)
- July: Continue beneficial insect releases
- August: Harvest regularly to remove pest-attracting overripe fruit
- August: Remove finished plants promptly
- August: Plan autumn prevention strategies
Autumn Tasks (September-November)
- September: Reduce monitoring to twice weekly
- September: Begin removing finished plants and debris
- September: Assess and repair greenhouse structure
- October: Complete major cleaning before winter
- October: Treat any remaining pest problems
- October: Install winter insulation carefully
- November: Final greenhouse inspection
- November: Minimise plants for winter
- November: Order next year's beneficial insects
Winter Tasks (December-February)
- December: Weekly trap monitoring
- December: Adjust watering for dormant season
- January: Monthly plant inspections
- January: Plan next year's pest management strategy
- February: Begin spring cleaning preparation
- February: Service pest control equipment
Spring Setup (March-May)
March - Big Cleanup
March is fresh start month. Complete annual deep clean before warming temperatures wake up overwintering pests. Remove all plant debris and organic matter where pests might have spent winter.
Check greenhouse structure for damage that could let pests in. Seal gaps around doors, vents, and glazing.
Start monitoring with sticky traps positioned throughout your greenhouse.
Service ventilation, heating, and automatic controls.
April - Early Detection
April's warming triggers rapid pest reproduction. Many UK greenhouse pests complete their first generation during April when populations are still manageable.
Increase monitoring to twice weekly, checking both traps and plant material. Focus on new growth, flower buds, and leaf undersides.
Release beneficial insects if monitoring shows emerging problems. Soil needs 15°C consistently for ground-dwelling beneficials, air temperatures above 18°C for flying beneficial insects.
Start companion planting with marigolds and herbs.
May - Active Management
May brings the first serious pest challenges as overwintering populations mature and new generations emerge.
Switch to daily observation during routine activities. Early May detection allows targeted treatments while populations remain localised.
Apply organic sprays at first sign of activity. May's moderate temperatures provide ideal conditions for organic treatment effectiveness.
Adjust watering to avoid conditions that encourage fungus gnats and moisture-dependent pests.
Summer Vigilance (June-August)
June - Peak Season Management
June is peak breeding season for most UK greenhouse pests. Intensive management prevents population explosions.
Daily monitoring becomes crucial. Tomatoes, cucumbers, and peppers often show first serious infestations.
Implement weekly organic spray rotations if pest pressure exceeds acceptable levels.
Manage environment carefully to prevent heat stress. Provide adequate shading, ventilation, and air circulation.
Remove heavily infested plant material promptly.
July - Heat and Stress Management
July's heat creates ideal conditions for spider mites while stressing plants. Environmental management becomes as important as direct pest control.
Monitor temperature and humidity closely, maintaining air circulation to prevent hot, dry conditions that favour spider mite reproduction.
Increase watering frequency while ensuring good drainage.
Continue beneficial releases if needed, focusing on heat-tolerant species.
Harvest regularly to remove overripe fruits that attract pests.
August - Sustained Effort
August maintains peak pest pressure while preparing for autumn transition.
Maintain intensive monitoring and treatment protocols.
Begin planning autumn management by identifying problem areas.
Remove finished plants promptly to eliminate breeding sites.
Autumn Preparation (September-November)
September - Transition Time
September's cooling begins slowing pest reproduction while creating opportunities for overwintering prevention.
Reduce monitoring frequency to twice weekly but maintain vigilance for late-season infestations that might overwinter.
Begin autumn cleanup by removing finished plants and organic debris.
Assess and repair infrastructure before winter.
Plant winter crops in clean medium using sterilised containers.
October - Winter Prep
October begins serious winter preparation, shifting focus from active control to overwintering prevention.
Complete major cleaning projects before cold weather limits working conditions.
Inspect and treat remaining plants for existing pest problems.
Install winter insulation carefully to avoid creating pest hiding places.
November - Final Preparations
November completes winter prep while implementing final prevention measures.
Conduct final greenhouse inspection, addressing remaining pest problems before cold weather makes treatment difficult.
Minimise plant material to reduce overwintering habitat.
Position monitoring traps for winter surveillance.
Prepare next season's materials and orders.
Winter Watching (December-February)
December-January - Quiet Monitoring
Winter's cold dramatically reduces pest activity, allowing reduced intervention while maintaining surveillance.
Check traps weekly, noting activity that might indicate problems.
Maintain minimal watering that prevents both plant stress and moisture conditions supporting fungus gnats.
Inspect plants monthly, particularly near heating systems.
Plan next season's strategies.
February - Spring Prep Begins
February starts spring preparation as increasing daylight stimulates both plant growth and pest activity.
Begin planning major spring cleaning, ordering materials and scheduling work.
Increase monitoring frequency as warming conditions may activate overwintering pests.
Service pest control equipment for spring activity.
Review and update protocols based on winter observations.
When You Need Professional Help
Sometimes DIY pest control isn't enough. Know when to call professionals to save your crops.
Emergency Action Decision Tree
Situation | Immediate Action | Next Steps | When to Call Professionals |
---|---|---|---|
Few pests spotted | Increase monitoring | Apply soap spray if spreading | Not needed |
Moderate infestation | Soap spray + beneficial release | Monitor daily, repeat treatments | If no improvement in 2 weeks |
Heavy infestation | Immediate organic spray treatment | Release multiple beneficial species | If >50% plants affected |
Multiple pest types | Identify all species first | Coordinate multiple treatments | If more than 2 species |
Valuable plants at risk | Isolate affected plants | Intensive treatment programme | Consider immediately |
Recurring problems | Review prevention measures | Check for underlying causes | If problems persist after 3 treatments |
Cost-Effective Treatment Comparison
Treatment Method | Initial Cost | Ongoing Cost | Effectiveness | Duration | Best For |
---|---|---|---|---|---|
Soap Spray | £3-5 | £2 per month | Good | 3-5 days | Small infestations |
Neem Oil | £8-12 | £5 per month | Very Good | 7-14 days | Multiple pest types |
Ladybirds | £15-25 | £15 per season | Excellent | 3-6 months | Aphid problems |
Sticky Traps | £10-15 | £20 per year | Good | 4-6 weeks | Monitoring/flying pests |
Copper Tape | £20-30 | None | Excellent | 2-3 years | Slug prevention |
Professional Treatment | £100-300 | Variable | Excellent | Variable | Severe infestations |
When You're Out of Your Depth
Severe Infestations
When pests cover more than half your plants despite consistent natural control efforts, professional intervention often provides the intensive treatment needed.
Multiple pest species attacking simultaneously create complex problems needing coordinated strategies beyond typical home management.
Valuable collections including rare varieties or crops you depend on justify professional treatment when pest pressure threatens significant losses.
Persistent Problems
Recurring issues that return repeatedly despite proper management may indicate underlying problems requiring professional diagnosis.
Professionals have diagnostic tools for identifying sources that escape amateur detection.
Some species including certain vine weevil populations require professional-grade methods not available to home growers.
UK Professional Services
Choosing the Right Help
Several UK companies specialise in greenhouse pest control. Research providers to ensure they understand greenhouse environments and sustainable management.
Look for BPCA (British Pest Control Association) certification demonstrating competency in modern techniques.
Request detailed plans explaining identification, methods, expected outcomes, and follow-up procedures.
Understanding Costs
Professional greenhouse pest control typically costs £100-300 for initial consultation and basic treatment in home greenhouses.
Compare costs against potential crop losses and time investment for extensive DIY efforts.
Many services offer integrated programmes combining consultation, beneficial supply, and monitoring.
Getting Ready
Document problems thoroughly including photographs, affected plant lists, and problem chronology.
Maintain records of previous control attempts including products used, timing, and results.
Prepare questions about long-term prevention and integration with ongoing DIY efforts.
Common Mistakes That Make Things Worse
Know what not to do—many well-meaning gardeners accidentally create bigger problems.
The Chemical Treatment Trap
Why Chemicals Often Backfire
Reaching for pesticides at first pest sign often disrupts natural predator-prey balances, creating worse problems than the original infestation.
Repeated applications select for resistant pest populations while eliminating susceptible beneficials.
Chemical dependency develops when gardeners lose confidence in natural methods after experiencing immediate chemical results.
Understanding Limitations
Even organic pesticides disrupt ecosystems when used inappropriately.
Systemic treatments affect plants throughout growth cycles, potentially impacting pollinators and beneficials for weeks.
Poor timing reduces effectiveness while maximising impact.
Ignoring Early Warnings
The Cost of Waiting
Small populations detected early often need minimal intervention, while the same pests can overwhelm crops if allowed to establish.
Sticky traps provide clear early warning, but many gardeners check irregularly or ignore moderate captures.
Plant symptoms appear weeks after establishment when populations have reached damaging levels.
Building Better Habits
Create monitoring routines that integrate with regular activities.
Document observations systematically, even negatives.
Establish clear thresholds triggering intervention before visible damage.
Poor Hygiene Practices
Sanitisation Shortcuts
Leaving debris provides overwintering sites and breeding habitat.
Using garden soil or unsterilised compost introduces eggs, larvae, and soil species directly.
Sharing tools between outdoor and greenhouse areas transfers pests.
Effective Hygiene Systems
Establish separate "clean" and "dirty" tool sets.
Create quarantine procedures for all incoming materials.
Schedule regular cleaning rather than attempting major cleanups only when problems develop.
Timing Errors
Missing Critical Windows
Many treatments prove most effective during specific life stages or seasons.
Beneficial releases need proper conditions and prey availability.
Organic sprays work best during moderate temperatures when pests are active but plants aren't stressed.
Understanding UK Patterns
Learn pest cycles specific to UK conditions.
Plan activities around weather and seasonal transitions rather than calendar dates.
Coordinate multiple strategies to work together rather than conflict.
Your Questions Answered
-
What are the most common greenhouse pests in the UK?
The main ones are aphids (greenfly and blackfly), whitefly, red spider mites, slugs and snails, and vine weevil. These love our mild, damp climate and cosy greenhouse conditions. Aphids usually show up first in spring, red spider mites become problematic during hot summer weather, slugs stay active year-round in heated greenhouses, and vine weevil can attack both leaves and roots throughout the growing season.
- Do natural pest control methods actually work in UK greenhouses?
- When should I be most worried about pests in my UK greenhouse?
- How often should I check for pests?
- Can I use the same pest control for food crops and flowers?
- How do I stop pests getting into my greenhouse in the first place?
- Where can I buy beneficial insects in the UK?
- When should I call in professional pest controllers?
- What's the biggest mistake people make with greenhouse pest control?
- Do different seasons need different pest control approaches?
Wrapping Up
Successful greenhouse pest control in the UK isn't about becoming a pest expert or buying expensive treatments. It's about understanding that your greenhouse is a living system that needs balanced management, not panic reactions to every bug you see.
The most important thing? Prevention beats treatment every time. A clean greenhouse with good ventilation, proper plant spacing, and basic hygiene creates conditions where pests struggle while beneficial insects thrive.
Natural pest control methods aren't just alternatives—they often work better than chemicals, especially in greenhouse environments. Our temperate UK climate actually favours biological controls, and organic treatments remain effective at the moderate temperatures we typically maintain.
The real key to success is developing good habits: weekly monitoring during growing season, annual deep cleaning, quarantining new plants, and keeping records of what works in your specific conditions. Every greenhouse develops its own patterns.
Remember that pest management is an ongoing process, not a series of emergencies. Gardeners who stay on top of prevention rarely face serious infestations, while those who wait for problems often find themselves fighting losing battles.
Your greenhouse should be your happy place—somewhere you enjoy spending time, not a constant source of stress and pest battles. Get your prevention sorted, stay observant, and act early when you spot problems.
For equipment to maintain optimal growing conditions that naturally discourage pest problems—from automatic vent openers to greenhouse staging that improves air circulation—visit Greenhouse Stores.
Equipment and Supplies Shopping List
Essential Items (£50-100 total)
- Digital min-max thermometer (£15-20)
- Hygrometer (£10-15)
- Sticky yellow traps x12 (£10-15)
- Pure castile soap 500ml (£5-8)
- Neem oil 250ml (£8-12)
- Copper tape 4m roll (£15-20)
- Fine spray bottle (£5-10)
Beneficial Insects (£40-80 per season)
- Ladybirds for aphid control (£15-25)
- Encarsia wasps for whitefly (£20-30)
- Predatory mites for spider mites (£15-25)
Professional Equipment (Optional £100-200)
- Magnifying glass with light (£20-30)
- Professional spray gun (£30-50)
- Automatic vent openers (£40-60)
- Circulation fans (£30-50)
Need More Help?
- Royal Horticultural Society - Biological Pest Control
- Defra - Sustainable Pest Management
- Garden Organic - Chemical-Free Methods
- Natural England - Environmental Approaches
More Greenhouse Growing Guides:
- How to Clean and Maintain Your Greenhouse
- The Best Way to Insulate a Greenhouse
- 6 Essential Greenhouse Growing Tips for Beginners
- Best Position for a Greenhouse UK