Greenhouse Growing Guide
Written by Matt W | Co-Founder, Greenhouse Stores
Last updated: February 2026 | Fact-checked by Matt W
I've grown tomatoes, chillies, and herbs in my own greenhouse for over 15 years, and the single biggest lesson I've learned is this: a greenhouse doesn't do the work for you, but it gives you a 6-to-8-week head start on the growing season that changes everything. In our trials at Greenhouse Stores, we've consistently recorded internal temperatures 8–12°C warmer than outside during spring, which means you can sow tomato seeds in February and be picking fruit by late June. This guide covers what I've learned from growing my own crops and from helping over 150,000 UK customers get the most from their greenhouses since 2012.
Key Takeaways
- A greenhouse extends your UK growing season by 6–8 weeks at each end, giving you fresh produce from March through November
- Keep temperatures between 18–24°C for most crops — anything above 27°C causes heat stress and blossom drop in tomatoes
- Ventilation is your biggest priority in summer — open roof vents when the temperature hits 20°C and aim for 15–20% of floor area as vent space
- Tomatoes, cucumbers, peppers, and chillies are the four highest-value greenhouse crops for UK growers, saving you £150–£300 per year on shop-bought produce
- Water in the morning before 10am to let foliage dry before cooler evenings, reducing fungal disease risk by up to 60%
- Replace greenhouse border soil every 3–4 years with fresh John Innes No. 2 compost to prevent soil-borne disease build-up
Setting Up Your Greenhouse for Growing
Before you plant anything, getting the setup right makes the difference between a productive greenhouse and a frustrating one. I've seen thousands of customers over the years make the same three mistakes: wrong position, no base preparation, and not enough ventilation. Here's how to avoid all three.
Choosing the Right Location
Position your greenhouse to face south or south-east for maximum light. In the UK, a greenhouse in a south-facing position receives around 6–8 hours of direct sunlight during spring and summer, compared to just 3–4 hours in a north-facing spot. That difference directly affects how early you can start sowing and how well heat-loving crops like tomatoes ripen.
Keep it away from overhanging trees. Falling branches damage glazing (we process around 200 replacement glass claims per year, and trees are involved in about 40% of them), and leaf litter blocks gutters and reduces light. A gap of at least 2 metres from any building or fence helps with air circulation too.
Shelter from prevailing winds matters more than most people think. A greenhouse exposed to strong westerly winds loses heat 15–20% faster than a sheltered one. A hedge or fence at a distance of about 3–5 metres on the windward side gives good protection without casting shadows. For more on this, our positioning guide covers wind exposure in detail.
Foundation and Base Preparation
Almost every greenhouse needs a proper base — and this is the step most beginners skip. A level concrete pad or paving slab base keeps the frame square, prevents twisting over time, and stops ground frost from creeping in. Without it, doors won't close properly, glazing panels can crack from frame movement, and your greenhouse lifespan drops significantly.
For most aluminium greenhouses (6x8ft and larger), we recommend a concrete base at least 75mm deep. Smaller models like 6x4ft greenhouses can sit on a level paving slab base. Budget around £150–£400 for base preparation depending on size. Our base preparation guide walks through each option step by step.
Choosing the Right Glazing for Growing
Your choice of glazing directly affects how well your greenhouse holds heat and protects your plants. Here's how the three main options compare for growing:
| Glazing Type | Light Transmission | Safety Rating | Heat Retention | Best For | Matt's Verdict |
|---|---|---|---|---|---|
| Horticultural Glass | 90% | Low (sharp shards if broken) | Standard | Budget-friendly growing | Best value if no children or pets nearby |
| Toughened Safety Glass | 91% | High (crumbles into granules) | Good | Most UK gardens | My top pick — safe, clear, and lasts 25–30 years |
| 4mm Twin-Wall Polycarbonate | 82% | Very high (virtually unbreakable) | Better (double-layer insulation) | Exposed or windy sites | Good for coastal gardens; less light means slower ripening |
| 6mm Twin-Wall Polycarbonate | 78% | Very high | Best (thicker air gap) | Cold or very exposed areas | Best insulation but reduced light — winter crops may struggle |
| 16mm Triple-Wall Polycarbonate | 72–76% | Very high | Excellent | Heated greenhouses, year-round growing | Saves most on heating but noticeably less light |
For most growers, toughened glass gives the best balance of light, safety, and durability. Polycarbonate makes sense if you're in a high-wind area or plan to heat your greenhouse through winter, as the insulation savings quickly add up. Our buying guide covers glazing options in more detail.
Interior Layout: Staging, Benches, and Floor Space
A well-organised greenhouse produces 30–40% more than one where everything sits on the floor. Greenhouse staging gives you working-height space for seed trays and young plants, and the area underneath is perfect for storing pots, overwintering tubers, or growing shade-tolerant crops.
I'd suggest staging along one side and leaving the other side for border planting or grow bags. If your greenhouse is 8ft wide or more, you can run staging down both sides with a central path of at least 60cm (anything narrower and you'll be constantly knocking plants over).
🔧 Matt's Growing Tip: The Staging Mistake Everyone Makes
I see this all the time: customers fill their greenhouse with staging, then wonder why they can't grow tomatoes or cucumbers properly. These tall, vining crops need floor-level grow bags or border soil, not staging. My advice: use staging for no more than 50% of your floor space. Leave at least one side clear for your main summer crops. You'll thank yourself in June when your tomato plants are 1.5 metres tall and need room to breathe.
Temperature and Ventilation Control
Getting temperature right is the single biggest factor in greenhouse growing success. Most greenhouse crops grow best between 18–24°C during the day and 10–15°C at night. Go above 27°C and you'll see blossom drop on tomatoes, bolting in lettuce, and wilting in cucumbers. Go below 5°C and tender seedlings will die.
Understanding Greenhouse Temperatures by Season
| Season | Daytime Target | Night-time Target | Action Required |
|---|---|---|---|
| Early Spring (Feb–Mar) | 12–18°C | 5–10°C | Heat overnight, ventilate on sunny afternoons |
| Late Spring (Apr–May) | 18–24°C | 10–14°C | Open vents by mid-morning, close before dusk |
| Summer (Jun–Aug) | 20–27°C max | 14–18°C | Full ventilation, shading, damp down floors |
| Early Autumn (Sep–Oct) | 15–22°C | 8–12°C | Reduce ventilation, remove shading |
| Late Autumn (Nov) | 8–15°C | 3–7°C | Insulate with bubble wrap, start heating |
| Winter (Dec–Jan) | 5–10°C | 2–5°C (frost-free) | Heating and insulation, minimal ventilation |
A good min/max thermometer costs under £10 and is the best investment you'll make. Check it daily and keep a simple log — after a few weeks, you'll know exactly how your greenhouse behaves in different weather.
Ventilation: The Most Important Factor
If you remember one thing from this guide, make it this: you need more ventilation than you think. The RHS recommends that roof vents should equal 15–20% of the greenhouse floor area. For a standard 8x6ft greenhouse (4.5m²), that means roughly 0.7–0.9m² of vent opening.
On a sunny April day, an unventilated greenhouse can hit 40°C+ within 2 hours of sunrise. That will kill seedlings. Open your roof vents when the internal temperature reaches 20°C and add louvre side vents for cross-flow air movement.
Automatic vent openers (around £20–£35 each) are worth every penny. They use a wax cylinder that expands with heat — no electricity needed. I fit them on every vent in my own greenhouse and they've saved my plants on days when I've been at work and the sun came out unexpectedly. You can find these in our accessories range.
Heating Your Greenhouse in Winter
An unheated greenhouse in the UK typically stays 3–5°C above the outside temperature. That's enough to keep hardy crops like winter lettuce alive, but it won't protect tender plants from a hard frost. For frost protection (keeping the minimum at 2–3°C), a 2kW electric fan heater running on a thermostat costs roughly £40–£80 per winter in electricity for a standard 8x6ft greenhouse.
Bubble wrap insulation (applied to the inside of the glass) reduces heat loss by around 30–40% and costs under £15 for most greenhouses. It's the cheapest improvement you can make. For detailed heating options and running costs.
Shading and Cooling in Summer
From May to September, shading prevents leaf scorch and keeps temperatures manageable. You've got three options: shading paint (cheapest at around £8 per tin, applied to the outside of the glass), internal roller blinds (best control but more expensive), or shade netting (good middle ground).
Damping down — wetting the greenhouse floor and paths with water — cools the air by 3–5°C through evaporation. Do this 2–3 times on hot days. It also raises humidity, which suits cucumbers and peppers.
Watering and Humidity Management
Water in the morning, before 10am. This gives foliage time to dry before the cooler evening temperatures arrive, which reduces the risk of fungal diseases like grey mould and blight. Wet leaves sitting in cool, still air overnight is the number one cause of disease in a greenhouse.
In summer, greenhouse plants need watering daily — sometimes twice on hot days. Tomatoes in grow bags are especially thirsty: a mature tomato plant drinks 2–4 litres per day in July and August. Inconsistent watering causes blossom end rot, fruit splitting, and poor flavour.
Collect rainwater from your greenhouse gutters into a water butt. Rainwater is slightly acidic (pH 5.5–6.5), which most greenhouse crops prefer over alkaline tap water. Let stored water reach greenhouse temperature before using it — cold water shocks plant roots and slows growth.
🔧 Matt's Growing Tip: The Watering Mistake That Kills Tomatoes
The most common problem I hear from customers is blossom end rot on tomatoes. Nine times out of ten, it's caused by irregular watering — not a calcium deficiency like many guides claim. If you go from dry to soaked and back again, the plant can't take up calcium properly. The fix is simple: water the same amount at the same time every day. If you're going away for a weekend, set up a basic drip irrigation system (from about £15) rather than soaking the plants before you leave.
Greenhouse Growing Month by Month in the UK
This month-by-month calendar is based on growing conditions in central England (roughly the Midlands). If you're in Scotland or northern England, shift sowing dates back by 1–2 weeks. In the south of England, you can often start 1–2 weeks earlier.
| Month | Greenhouse Tasks | What to Sow and Plant |
|---|---|---|
| January | Keep frost-free (min 2°C). Check heaters are working. Water sparingly — overwatering in cold weather causes root rot. Order seeds and compost. Clean pots and seed trays. | Sow early lettuce and radish in trays. Start sweet peas in root trainers. Chit early potatoes on the staging. Force hyacinth and narcissus bulbs. |
| February | Clean glass inside and out for maximum light. Start heated propagator (18–21°C). Check for slug damage. Prepare seed trays and compost. | Sow tomatoes in a heated propagator (21°C). Sow peppers, chillies, and aubergines (need 18–21°C to germinate). Start onions, leeks, and broad beans. |
| March | Ventilate on warm days (above 15°C). Heat overnight. Watch for greenfly, whitefly, and red spider mite. Start liquid feeding young plants. | Prick out tomato seedlings. Sow cucumbers (20°C). Start courgettes, French beans, celery, and sweetcorn. Take fuchsia and chrysanthemum cuttings. |
| April | Open roof vents daily. Start shading on south-facing glass if temperatures hit 25°C+. Reduce heating. Remove insulation. | Plant tomatoes into final positions (grow bags or 25cm pots). Plant cucumbers into grow bags. Sow runner beans, squash, and melons. Harden off brassica seedlings for outdoor planting. |
| May | Full ventilation in warm weather. Start damping down floors. Feed and water daily. Tie in tomato plants and remove side shoots weekly. | Plant out courgettes, beans, and sweetcorn after hardening off. Make up hanging baskets. Harvest early lettuce, radish, and strawberries. |
| June | Maximum ventilation and shading. Damp down 2–3 times daily in hot weather. Stop heating and service heaters for storage. Check plants for pests twice weekly. | Harvest early tomatoes, cucumbers, lettuce, and French beans. Move bedding plants and hanging baskets outside. Feed tomatoes weekly with high-potash feed. |
| July | Keep on top of watering (twice daily in heatwaves). Continue shading. Take softwood cuttings. Watch for red spider mite (fine webbing on leaves). | Harvest tomatoes, cucumbers, peppers, aubergines, and chillies. Sow winter lettuce varieties and carrots for autumn. Peg down strawberry runners for next year. |
| August | Watch for mould in humid weather. Continue feeding fruiting crops. Order spring-flowering bulbs. Take fuchsia and pelargonium cuttings. | Continue harvesting summer crops. Plant hyacinth and narcissus bulbs for Christmas. Sow autumn lettuce and spinach. Plant potatoes in pots for a Christmas crop. |
| September | Remove shading. Reduce ventilation as temperatures drop. Bring tender plants (fuchsias, pelargoniums) inside before first frost. Clean up spent crops. | Sow winter salad leaves and spring onions. Plant garlic cloves in modules. Harvest remaining tomatoes, peppers, and aubergines. Pull out finished cucumber plants. |
| October | Insulate with bubble wrap. Start heating if temperatures drop below 5°C at night. Reduce watering. Remove dead leaves and debris to prevent mould. | Plant tulip, crocus, and snowdrop bulbs for spring. Lift tomato plants once cropping finishes. Sow broad beans and peas for overwintering. Plant winter pansies for colour. |
| November | Clean glass, framework, and staging with garden disinfectant. Repair cracked panes. Check heating works. Clear gutters of leaves. | Store dahlia tubers and fuchsia plants under staging. Pot up herbs (chives, parsley, mint) for winter supply. Sow cold-tolerant lettuce varieties. Try starting mushrooms in a cool, dark spot under the staging. |
| December | Keep greenhouse dry and well-ventilated on mild days. Check heaters regularly. Tidy pots, trays, and tools ready for the new year. | Plan next year's growing schedule. Order seeds from catalogues. Force rhubarb crowns in a dark corner. Keep overwintering plants frost-free. |
Best Crops to Grow in a UK Greenhouse
After 15+ years of growing and talking to thousands of customers about their harvests, these are the crops that give UK greenhouse growers the best results in terms of yield, flavour, and value for space.
Tomatoes
Tomatoes are the number one reason people buy a greenhouse in the UK. A single cordon tomato plant can produce 3–5kg of fruit over a season, and six plants (a comfortable number for a 6x8ft greenhouse) can yield 18–30kg of tomatoes between July and October. At supermarket prices, that's £45–£90 worth of tomatoes from about £5 in seeds and compost.
Sow seeds at 21°C in February, transplant into 25cm pots or grow bags in April, and remove side shoots weekly. Feed with a high-potash tomato feed once the first truss sets. Shake the flower trusses gently at midday to help pollination — there aren't enough bees inside a greenhouse to do the job reliably.
For detailed growing instructions, see our greenhouse tomato growing guide.
Greenhouse cucumbers produce smoother, longer fruit than outdoor varieties and crop heavily from June through September. Choose all-female varieties (like 'Passandra' or 'Bella') to avoid bitter fruit — these don't need pollinating.
Cucumbers prefer higher humidity than tomatoes (around 70–80%), so growing them in a separate section or at the far end of the greenhouse from your tomatoes works best. Train the main stem up a string or cane, and pinch out the growing point when it reaches the roof. Each plant can produce 20–30 cucumbers over a season.
See our cucumber growing guide for full instructions.
Peppers and Chillies
Sweet peppers and chillies are slow starters — they need a long growing season, which makes them ideal for greenhouse growing. Sow in February at 18–21°C and don't expect to harvest until late July at the earliest. A single pepper plant produces 5–8 fruits; a chilli plant can give you 20–50+ fruits depending on variety.
Pinch out the growing tip when the plant reaches about 20cm tall to encourage bushier growth. Chillies get hotter when they're slightly stressed (less water, more sun), so don't be too generous with the watering can once the fruits are forming. Our pepper growing guide covers varieties and feeding in detail.
Aubergines
Aubergines need the warmest spot in your greenhouse and a longer season than tomatoes. Sow in January or February at 21°C. They're slower growing, so don't panic if germination takes 2–3 weeks. Limit each plant to 5–6 fruits for the best size and flavour. Mist the foliage daily with tepid water to deter red spider mite.
Lettuce and Salad Leaves
Lettuce is the quickest-reward crop for greenhouse growers. Sow direct into trays and you can cut your first leaves in as little as 3–4 weeks. "Cut and come again" varieties give you multiple harvests from one sowing. You can grow lettuce in a greenhouse for about 9–10 months of the year — only the hottest summer weeks cause bolting.
Succession sow every 2–3 weeks for a continuous supply. A 60cm tray of mixed salad leaves costs about 50p in seeds and produces the equivalent of 3–4 supermarket bags worth £6–£8.
Herbs
Basil, coriander, parsley, chives, and mint all grow brilliantly in a greenhouse. Basil is especially good value — a single plant produces leaves worth £10–£15 over a season compared to buying fresh packs. Pot up outdoor herbs like chives, parsley, and mint in October and bring them inside for fresh winter pickings. For a complete setup guide, see our herb garden guide.
Strawberries
Greenhouse strawberries fruit 3–4 weeks earlier than outdoor plants and avoid the slug damage that ruins so many outdoor crops. Grow them in hanging baskets, stacked planters, or pots on staging to save floor space. A single plant produces 200–400g of fruit per season, and runners peg down easily to give you free plants for next year. See our strawberry growing guide for the best varieties.
Exotic and Unusual Crops
A greenhouse opens up crops that don't normally grow outdoors in the UK. Melons (try 'Charentais' or 'Sweetheart'), physalis (ground cherries), ginger, and even orchids all thrive in a warm greenhouse. For more ideas, our guide to 25 unusual things to grow in a greenhouse is worth a read if you've got the basics covered and want to try something different.
More Crops You Can Start in a Greenhouse
Beyond the main crops above, a greenhouse is a brilliant place to germinate and grow on these vegetables, leafy greens, and cucurbits before transplanting them outdoors or keeping them under glass all season:
Asian Greens
Broccoli
Brussels Sprouts
Cabbage
Kale
Chard
Spinach
Endive
Gourds & Pumpkins
Melons
Squash
Potatoes
Physalis
Pepino
Greenhouse Pest and Disease Management
A warm, sheltered greenhouse is perfect for your plants — and for pests. The enclosed environment means populations can build up fast, so early detection is everything.
Common Greenhouse Pests
Red spider mite: Tiny (0.5mm) mites that live on the undersides of leaves, causing yellowing and fine webbing. They thrive in hot, dry conditions. Raise humidity by misting and damping down. Biological control (Phytoseiulus persimilis) works well if introduced early in the season (May–June).
Whitefly: Small white flying insects that cluster on the undersides of leaves, particularly on tomatoes. Hang yellow sticky traps above plants from April to give early warning. Encarsia formosa (a tiny parasitic wasp) is the most effective biological control. Introduce it when daytime temperatures are consistently above 18°C.
Aphids (greenfly/blackfly): Sap-sucking insects that weaken plants and spread viruses. Squash small colonies by hand or blast with a spray of water. Introduce ladybird larvae for biological control.
Disease Prevention
Most greenhouse diseases come down to poor air circulation and wet foliage. Keep these three rules and you'll avoid 80% of problems:
- Ventilate, ventilate, ventilate. Still, humid air breeds grey mould (botrytis) and mildew.
- Water at soil level, not from above. Wet leaves in cool evenings are the main cause of fungal outbreaks.
- Clean up. Remove dead leaves, spent plants, and fallen fruit immediately. These harbour disease spores.
An autumn deep clean (removing all plants, washing glass and framework with garden disinfectant, scrubbing pots) reduces pest and disease carry-over by 70–80%. This takes a couple of hours but makes a huge difference to next year's growing.
Maximising Your Greenhouse Space
Greenhouse space is always at a premium. These three techniques help you produce more from the same footprint.
Succession Planting
Don't leave empty space after a crop finishes. As soon as you pull out the spring lettuce in May, plant your tomato grow bags in the same spot. When tomatoes finish in October, sow winter salad leaves immediately. A well-planned greenhouse is producing something 10–11 months of the year.
Vertical Growing
Train cucumbers, tomatoes, and beans upwards on strings or canes rather than letting them sprawl. Hanging baskets inside the greenhouse work for strawberries and trailing tomato varieties like 'Tumbling Tom'. This approach can increase your productive growing area by 40–50% in a small greenhouse.
Companion Planting
Basil planted alongside tomatoes is said to improve flavour, though the real benefit is practical: basil attracts pollinators while repelling whitefly. French marigolds at the base of tomato plants help deter whitefly and aphids. These combinations work well in limited greenhouse space where every centimetre counts.
Greenhouse Accessories That Make a Difference
After years of testing different setups, here are the accessories I'd recommend to any greenhouse grower, in order of priority:
| Accessory | Approx. Cost | Why It's Worth It |
|---|---|---|
| Min/max thermometer | £8–£15 | Know your actual temperatures — guessing costs you plants |
| Automatic vent openers | £20–£35 each | Saves plants on unexpectedly hot days when you're out |
| Staging and shelving | £35–£120 | Doubles your growing space and puts plants at working height |
| Heated propagator | £25–£60 | Starts seeds 4–6 weeks earlier than unheated sowing |
| Drip irrigation kit | £15–£30 | Consistent watering prevents blossom end rot and splitting |
| Bubble wrap insulation | £10–£20 | Reduces heat loss by 30–40% and cuts winter heating bills |
| Yellow sticky traps | £4–£8 | Early pest detection before infestations take hold |
| 2kW electric fan heater | £40–£80 | Frost protection extends your growing season by 2–3 months |
You can find all of these in our accessories range, or call us on 0800 098 8877 for advice on the best setup for your greenhouse size.
Common Greenhouse Growing Mistakes to Avoid
After helping 150,000+ customers and growing in my own greenhouse for 15 years, these are the mistakes I see over and over again:
- Buying too small. Almost everyone buys a greenhouse that's too small the first time. If you think you need a 6x4ft, get an 8x6ft. You'll fill it within the first season.
- Not ventilating enough. Overheating kills more greenhouse plants than cold does. If in doubt, open another vent.
- Overwatering in winter. Plants need far less water when it's cold. Roots sitting in cold, wet compost rot quickly. Water only when the compost surface is dry.
- Skipping the base. A proper foundation adds years to your greenhouse's lifespan and keeps the frame square for doors and vents to work properly.
- Planting too early. It's tempting to sow tomatoes in January, but without a heated propagator, they'll be leggy and weak by planting time. February is early enough for most crops.
- Forgetting to feed. Tomatoes and peppers in grow bags exhaust the nutrients within 4–6 weeks. After that, weekly feeding with a high-potash fertiliser is needed or yields drop by 50%+.
- Ignoring the autumn clean. An hour spent cleaning in October saves weeks of pest and disease problems the following year.
Frequently Asked Questions
What is the best greenhouse for growing vegetables in the UK?
An aluminium-framed greenhouse with toughened glass, at least 6x8ft in size, gives most UK vegetable growers the best combination of light, durability, and value. Aluminium frames are low-maintenance, won't rot, and let in more light than wooden frames due to thinner glazing bars. Toughened glass holds heat better than polycarbonate and lasts 25–30 years. If budget allows, go bigger — you'll always use the space. Our greenhouse comparison guide covers the options in detail.
When should I start planting in my greenhouse in the UK?
You can start sowing in a UK greenhouse from January if you have a heated propagator, or from March without one. Cold-hardy crops like lettuce, spinach, and radish can be sown in trays from January. Heat-loving crops (tomatoes, peppers, cucumbers) need a heated propagator at 18–21°C and should be started in February or March. Without heating, wait until April when daytime greenhouse temperatures consistently reach 15°C+.
How do I stop my greenhouse overheating in summer?
Open all roof and side vents, apply shading to the glass, and damp down the floor 2–3 times daily. Automatic vent openers (£20–£35) react to temperature without electricity, keeping your greenhouse below 27°C even when you're not there. Shading paint or mesh reduces solar heat gain by 40–50%. If temperatures still climb above 30°C, open the door as well for through-draught ventilation.
Can I grow in my greenhouse all year round?
Yes, a UK greenhouse can produce crops for 10–11 months of the year with basic planning. Spring and summer are the peak growing season for tomatoes, cucumbers, and peppers. In autumn, sow winter lettuce, spinach, and spring onions. Over winter, the greenhouse protects herbs, forces rhubarb, and stores tender plants. Only December and January are truly quiet — and even then, you're cleaning, planning, and chitting potatoes. For winter-specific ideas, see our guide to winter greenhouse growing.
What temperature should I keep my greenhouse at?
Most greenhouse vegetable crops grow best between 18–24°C during the day and 10–15°C at night. In winter, the minimum target is 2–3°C (frost-free) for overwintering plants, or 7–10°C if you're growing winter salads. Temperatures above 27°C cause blossom drop in tomatoes and bolting in lettuce. A min/max thermometer (under £10) is the single most useful tool for monitoring conditions.
Do I need to water my greenhouse plants every day?
In summer, yes — most greenhouse plants need watering daily, and some (like tomatoes in grow bags) may need watering twice per day in hot weather. In spring and autumn, every 2–3 days is usually enough. In winter, reduce watering to once a week or less — cold, wet compost causes root rot. Water at the base of plants in the morning, never over the foliage, and always use water that's reached greenhouse temperature.
How do I pollinate plants inside a greenhouse?
For tomatoes and peppers, gently shake or tap the flower trusses at midday when pollen is most active. An electric toothbrush held against the flower stem works even better — it mimics the "buzz pollination" that bumblebees provide. For cucumbers, choose all-female (parthenocarpic) varieties that don't need pollinating. For melons and squash, use a small paintbrush to transfer pollen from male flowers to female flowers. Opening vents and the door on warm days also lets bees in to help.
More Growing Guides from Greenhouse Stores
This guide covers the big picture, but we've written detailed growing guides for individual crops too. These go deeper into varieties, feeding schedules, common problems, and harvest timing:
Need help choosing a greenhouse for growing?
If you're still deciding on the right greenhouse, our buying guide covers size, frame material, and glazing options. Or call our team on 0800 098 8877 (Mon–Fri, 9am–5:30pm) — we'll help you match the right greenhouse to your growing plans and budget.