Smart Garden Greenhouse Nuts & Bolts (15 Pack): Aluminium M6 x 11mm Bolts and Nuts for Aluminium Greenhouse Frames, Staging and Accessories

For the bolt that rolled under the staging

Anyone who has built an aluminium greenhouse knows the feeling. You've counted the bolts twice, you're three panels from finishing, and the last few have vanished. One is in the grass, one is down the gap behind the staging, and one, somehow, is in your pocket on the other side of the garden. Greenhouses are held together by dozens of small fixings, and every one of them is easy to lose and impossible to do without. The Smart Garden Greenhouse Nuts & Bolts 15pk is the spare jar every greenhouse owner ends up wishing they had.

What are Smart Garden Greenhouse Nuts & Bolts?

They're replacement and additional fixings for aluminium greenhouse frames, supplied as a pack of 15 bolts with matching nuts. The bolts are M6, which refers to their 6mm thread diameter, with an 11mm length under the head. Both are made from aluminium. They’re used to join frame sections, fix accessories to the frame, and replace bolts that have been lost, damaged or corroded.

Who makes them?

Smart Garden Products is a British garden products company based in Abingdon, Oxfordshire. It supplies a wide range of garden and greenhouse essentials, including growhouses, greenhouse accessories, meters and plant supports. These nuts and bolts sit in its greenhouse accessories range, alongside a cropped head version.

How do greenhouse bolts work?

Most aluminium greenhouses are built from extruded aluminium sections with a channel, or slot, running along them. Greenhouse bolts have a head shaped to sit inside that channel. Once in place, the head can't turn or pull out through the slot, so you can tighten the nut on the outside without having to hold the bolt. That’s what makes greenhouse construction so adjustable. Bolts can slide along the channel to line up with holes in other parts of the frame, brackets or accessories. Then they’re tightened in place once everything is where it should be.

What does M6 x 11mm mean?

M6 refers to the thread size. "M" means metric, and 6 is the thread diameter in millimetres. It's one of the most common sizes used in aluminium greenhouse construction. The 11mm figure is the under-head length, meaning the length of the threaded shank measured from the underside of the head to the tip. This determines how much material the bolt can pass through, such as two frame sections or a frame section plus a bracket, while still leaving enough thread for the nut.

Standard head or cropped head?

Greenhouse bolts usually come in two head styles, and Smart Garden offers both. Standard head bolts like these generally need to be slid into the channel from the open end of the frame section. This is the way most greenhouses are put together during the original build. It’s also the most common type to have spare when you’re assembling, extending or reglazing. Cropped head bolts have a head trimmed so it can be turned and dropped into the channel partway along. That’s handy when you need to add a bolt to a frame that’s already built and the channel ends aren’t accessible. If you’re adding fixings to a finished greenhouse and can’t reach the end of the channel, a cropped head bolt is usually the easier option. If you’re building, rebuilding or the channel end is open, standard head bolts are the usual choice.

Will these fit my greenhouse?

M6 bolts are widely used across aluminium greenhouses. However, the size and shape of the channel varies between manufacturers and models, so it's worth checking before you buy. To check compatibility: Compare with an existing bolt from your greenhouse, checking thread size, head shape and length. Measure the width of the slot in your frame channel and check that the bolt head sits inside it without spinning or falling through. Check the total thickness of what you’re bolting together, so the 11mm under-head length is long enough to pass through and leave room for the nut. If in doubt, take one of your existing bolts to compare. It’s the quickest way to be sure.

What are greenhouse nuts and bolts used for?

Uses include: Replacing bolts lost or damaged during the original build. Replacing old bolts that have seized, sheared or worn out. Fitting staging, shelving and shelf brackets to the frame. Fixing automatic vent openers, louvre vents and roof vents. Attaching guttering, downpipes and water butt kits to the frame. Mounting hanging basket brackets, shading fixings and insulation clips. Adding extra bracing and corner braces for strength in windy positions. Moving or re-erecting a greenhouse in a new spot, which almost always results in some bolts going missing.

Why aluminium?

Aluminium bolts are the usual match for aluminium greenhouse frames. Using the same metal throughout helps avoid the problems that can occur when dissimilar metals sit together in damp conditions. In some combinations, that can lead to corrosion where the metals meet. Aluminium is also lightweight and naturally resistant to rusting. That makes sense in a greenhouse, where condensation, watering and damp air are part of everyday life.

How do I fit greenhouse bolts?

For a standard head bolt: Slide the bolt head into the channel from the open end of the frame section, with the thread facing outwards. Slide it along to the position you need, lining it up with the hole in the part you’re fixing. Pass the thread through the hole, then fit the nut and tighten by hand. Once everything is lined up and square, tighten with a spanner or socket. Don’t overtighten. Aluminium threads are softer than steel and can strip if forced. Firm and snug is the aim. If you’re building a new greenhouse, many manufacturers recommend leaving bolts slightly loose until the whole frame is assembled and squared, then tightening everything at the end.

Check your greenhouse before winter

Autumn is the time to give the frame a once-over before the winter gales arrive. Loose bolts let panels and glazing move in strong wind, and that's how panes crack and frames twist. A quick check now saves an expensive repair later. Work your way round the frame and check: Any bolts that are loose or missing. Bolts that have sheared, seized or lost their thread. Fixings on doors, vents and roof sections, which take the most movement. Fixings holding the frame to its base, which keep the whole greenhouse anchored. Replace anything worn and tighten anything loose. A spare pack of bolts means the job can be done straight away, not left for the weekend you were going to buy them.

Tips for working with small fixings

Greenhouse bolts are small, and they have a habit of disappearing. A few tricks help: Lay an old sheet or tarpaulin on the ground beneath where you’re working, so dropped bolts can be found. Keep bolts in a small tub or magnetic tray rather than your pocket. Bear in mind magnets won’t hold aluminium, so a tub with a lid is better. Sort bolts by type before you start, especially if you have standard and cropped head bolts in the same project. Keep any spares in a labelled jar in the shed, so they’re ready for repairs and new accessories.

Frequently asked questions

How many bolts are in the pack? There are 15 bolts with matching nuts. What size are the bolts? They’re M6 bolts with an 11mm under-head length. What are they made from? Aluminium. Will they fit any greenhouse? They’re designed for aluminium greenhouse frames, but channel sizes vary between makes. Compare with an existing bolt from your greenhouse to check the fit. What’s the difference between these and cropped head bolts? Standard head bolts usually slide into the frame channel from the end. Cropped head bolts can typically be fitted partway along the channel on a frame that’s already assembled.

15 x Smart Garden greenhouse bolts with matching nuts

Key Features:

Dimensions:

Height: 1.5cm
Width: 0.58cm
Depth: 0.58cm
Weight: 30g