Essential Greenhouse Accessories: What You Actually Need
Eight greenhouse accessories are worth buying in the UK. Top of the list: auto-vent openers (from £46), aluminium staging (from £75), and a max-min thermometer (from £24). Auto-vents rank first because overheating kills more UK greenhouse plants than cold. Shade cloth, capillary matting, propagators, heaters, and drip systems complete the eight. Installers at Greenhouse Stores recommend buying ventilation before heating.
Key Takeaways
- Buy an auto-vent before anything else — a closed greenhouse hits 50°C on a warm day and cooks your plants
- Staging is the second priority — it doubles your growing space and saves your back
- Skip smart watering systems and electronic soil testers — a finger in the compost works better
- Insulate before you heat — bubble wrap saves more money than upgrading your heater
Installer's Note
After fitting over 3,000 greenhouses, I get asked the same question every time: "What accessories should I buy?" My answer has not changed in 14 years. An auto-vent opener and staging. Everything else is optional. Those two will keep your plants alive and give you somewhere to work. Add a thermometer if you want to know what is going on overnight.
The 8 greenhouse accessories worth buying
These are ranked by how much difference they make. We have installed every one of these on customer greenhouses and seen the results first-hand.
1. Automatic vent opener
This is the single most important greenhouse accessory you can buy. A sealed greenhouse on a sunny March day can hit 50°C inside. That is hot enough to kill seedlings in under an hour. Auto-vent openers use a wax cylinder that expands with heat. No batteries, no wiring, no electricity needed. The vent opens at around 15-20°C and closes when it cools.
We fit these on every greenhouse we install. One roof vent opener is enough for a 6x8ft greenhouse. For an 8x10 or larger, fit two. They cost from £46 for a Vitavia model up to £89 for a heavy-duty Bayliss MK7.
Losing plants to heat? Our guide on keeping your greenhouse cool in summer has more detail.
Louvre vents: extra airflow at plant level
Roof vents release hot air from the top. Louvre vents sit lower in the greenhouse frame and draw cool air in from the sides. The two work together. Hot air rises and escapes through the roof vent while fresh air enters through the louvre. On still summer days, this cross-ventilation makes a real difference.
We fit louvre vents on most greenhouses over 8ft long. A 5-blade louvre vent frame starts from £83. Add an automatic louvre opener (£59) so it opens and closes with the temperature, just like a roof vent. Most manufacturers offer louvre panels in glass, polycarbonate, or aluminium blades.
2. Aluminium staging
Staging raises your plants to working height (around 750mm) and doubles the usable space in your greenhouse. Without it, everything sits on the floor. Your back will hate you by June. Aluminium slatted staging allows air to circulate underneath. This reduces fungal problems and keeps roots healthier.
A folding single-tier costs from £75. Two-tier models start at £109. For a 6x8ft greenhouse, we recommend one full-length bench on each side. Our greenhouse size guide shows how staging fits different widths.
3. Max-min thermometer
A max-min thermometer records the overnight low and daytime peak. Check it each morning and you know exactly what happened while you slept. Did frost get in? Did the greenhouse overheat? This is how you learn what your greenhouse actually does through the seasons.
A basic analogue model costs from £24. A digital version with humidity readout costs £44. Place it at plant height, away from direct sunlight and the door.
4. Shade cloth or blinds
Even with auto-vents open, a south-facing greenhouse can overheat in July and August. Shade cloth blocks 30-50% of sunlight and drops the temperature by 5-10°C. External shade is more effective than internal because it stops heat entering the glass in the first place.
A Palram shade kit costs £52. Netting with clips starts from £99. Apply in May and remove in September.
5. Capillary matting
Capillary matting sits on your staging and wicks water up from a tray below. It keeps compost evenly moist without overwatering. Seedlings love it. It costs around £10-15 per roll and saves you from watering twice a day in summer. Cut it to fit your staging width.
6. Heated propagator
A heated propagator provides bottom heat for germination. Tomatoes need 18-21°C to germinate. Chillies need 27-32°C. In an unheated greenhouse in February, you will not hit those temperatures without help. A propagator extends your growing season by 4-6 weeks.
Worth buying if you start seeds early. Not needed if you only grow from plug plants.
7. Greenhouse heater
Most UK gardeners do not need a greenhouse heater. An unheated greenhouse stays 8-12°C warmer than outside on its own. A heater with a thermostat keeps temperatures above freezing for a few pence per night. Only worth it if you overwinter tender plants or grow year-round.
A tube heater starts from £75. A fan heater with thermostat starts from £140. Our guide on how to heat a greenhouse covers running costs in detail.
8. Drip watering system
If you go on holiday in July, your greenhouse plants will die within 48 hours. A basic gravity-fed drip system connected to a water butt solves this. Solar-powered kits exist but basic manual drip lines work just as well for far less.
5 greenhouse accessories that waste your money
Not everything sold as a greenhouse accessory is worth buying. These are the ones we see customers regret.
- Smart watering systems (£100+) — they malfunction regularly. A gravity drip kit does the same job for £20.
- Electronic soil testers (£30-80) — inaccurate out of the box. Put your finger in the compost instead. It is free and more reliable.
- Specialist grow lights (£200+) — standard LED shop lights at £20 deliver the same result for seedlings.
- Cedar potting benches (£300-500) — an old kitchen table with plastic sheeting works identically.
- Pre-made seed starting kits (£50-100) — modular trays at £5 do the same job. Save the money for an auto-vent.
Matt's Tip: Insulate before you heat
The biggest waste of money I see is buying a bigger heater when the greenhouse leaks heat. Fit bubble wrap insulation first. Seal the gaps around the door and vents. A £79 bubble wrap kit saves more on heating bills than any heater upgrade. Always insulate first.
What to buy first: the £150 starter pack
If you have just bought a greenhouse and want the essentials, here is what we recommend.
| Accessory | Why | Cost |
|---|---|---|
| Auto-vent opener | Prevents overheating when you are not there | £46 |
| Folding staging (1 tier) | Working surface and doubled growing space | £75 |
| Max-min thermometer | Know your overnight lows and daytime highs | £24 |
Total: around £150. Add shade cloth in summer and a heater in winter if needed. Browse our full range of greenhouse accessories to see what is available.
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Matt's Pick for most important greenhouse accessoryBest For: Every greenhouse owner, full stop Why I Recommend It: I fit these on every single greenhouse we install. A wax cylinder opens the vent at 15-20°C with no power needed. One opener handles a standard roof vent. It has saved more plants than any heater, propagator, or gadget I have seen in 14 years. Price: £46 |
Frequently asked questions
What accessories do I need for a new greenhouse?
An auto-vent opener, staging, and a thermometer are the three essentials. Together they cost around £150. The auto-vent prevents overheating, staging gives you a work surface, and a thermometer lets you track conditions overnight. Everything else depends on what you grow and when.
How many auto-vents does a greenhouse need?
One auto-vent opener per roof vent is standard. A 6x8ft greenhouse usually has one roof vent and needs one opener. An 8x10ft or larger may have two roof vents. Fit an opener on every vent that can take one. Louvre vents take a separate louvre-specific opener.
Do I need a heater in my greenhouse UK?
Most UK greenhouse gardeners do not need a heater. An unheated greenhouse stays 8-12°C warmer than outside. If you only grow spring to autumn, frost protection is rarely needed. Heaters become useful if you overwinter tender plants or start seeds in January and February.
What is greenhouse staging?
Staging is a slatted bench that raises plants to working height. Aluminium models last indefinitely and allow air circulation underneath. Standard staging sits at 750mm height. Folding versions store flat when not in use. Most greenhouse owners put staging on both sides with a path down the middle.
Is a greenhouse thermometer worth buying?
Yes, a max-min thermometer costs from £24 and pays for itself fast. It records the overnight low and daytime high. Without one, you are guessing whether frost got in or whether the greenhouse overheated. A digital model with humidity readout helps you spot fungal risk before it becomes a problem.
