Greenhouse Maintenance Checklist

This is an aide-memoir for those who just need a reminder and a starting point for those who are less knowledgeable.

Many of the points are of necessity general: greenhouses vary in size and materials.

What is the Greenhouse used for?

For example, is it for –

• sowing seeds and growing cuttings
• over wintering alpines and tender perennials
• growing vines, pineapples, melons
• does it house a permanent display of tender plants

How often the greenhouse is used may mean some maintenance tasks are forgotten, or that it is difficult to empty the greenhouse to carry them out. We are all of us guilty of these excuses. But working out what needs to be done and when, and having a process for checking is part of good management.

Who uses or has access to the Greenhouse?

• owners only
• staff only
• members of the public – supervised or unsupervised

Depending on who has access will determine the level of duty of care which needs to be taken. For example, if it is only the owner and family, an uneven brick path may be considered quaint.

Greenhouse Surroundings

This refers to the surroundings that could affect the greenhouse structure and its use.

Paths and walkways –

• Safe access for humans, equipment and plants. Are the
  paths wide enough for wheelbarrows / trolleys and is the surface even and not
  slippery?
• Is there access all round the greenhouse for
  maintenance?

Trees and shrubs –

• These may be providing shelter from the wind and / or
  shade in summer. Are they evergreen or deciduous? Deciduous will drop leaves in
  autumn to be cleared away from gutters; evergreens will lose fewer leaves but
  do year round.
• They will need to be pruned to ensure that branches
  are not overhanging or scratching the windows.

Adjacent sundries and structures

Cold frames and water butts are the two most likely and may be attached to the greenhouse.

Cold frames – follow general care for greenhouse frame

Water butts –

• check for leaks, including around the tap
• does the downpipe still fit cleanly in the gutter
• is there a means of controlling overflow? This may be
  a valve in the downpipe re-directing the flow to a soak away when the butt is
  full

Greenhouse Exterior

You may find binoculars and a ladder useful for closer inspection. If using a ladder, follow safety guidelines, falling through glass panes onto steel-edged staging is not recommended. For larger glasshouses it may be appropriate to bring in a specialised team who have the equipment to clamber over large expanses of glass.

General

• check all panes of glass for cracks and ensure firmly
  fixed in place within frame
• check ridge for any signs of movement
• lean-to glasshouses – check flashing where it joins
  the wall
• windows, louvres and doors should fit within frames
  without gaps
• use a level to check for general movement of the frame
• is there moss growing? – on a wooden greenhouse this
  may highlight a specific problem with rotting wood as well as generic dampness
• guttering and downpipes –
  • some models have integral guttering
  • check fittings are secure and that the guttering
    hasn’t slipped
  • are there any cracks to cause leaks?
  • do the sections all fit cleanly together
  • does the water drain into a butt or soak away? If the
    latter, is it clear? For example, no leaves clogging a drain cover.

Wooden Greenhouse

Check the frame for rotting, splitting, warping and splinters.

Do the joints matchup? If not, is this because of general movement or due to a particular part of the frame.

If it’s a softwood rather than hardwood structure then regular cleaning and application of preservative will be necessary. Hardwood greenhouses are more likely than softwood and far more durable. I would still recommend doing the checks and cleaning although preservative is not generally required.

If there are upvc or metal clips on vulnerable areas, check these are secure and in good repair.

Does the structure sit on a low brick wall, metal plate or onto concrete? Check all round for movement of the frame off this base.

The brick wall should be checked –

• could it do with a clean?
• does it need re-pointing?
• is it still straight?

There may be vents set into the brick – are they clear so air can pass through? If there’s a closing mechanism does this still function smoothly?

Metal Greenhouse

Most metal-framed greenhouses are made of aluminium which has the potential to ‘corrode’, rather than ‘rust’. This corrosion looks like a white bloom that grows on the metal. Generally it is slower to appear and is not as detrimental as rust.

• Aluminium
  also twists and bends under stress such as gales. So look over the structure
  for signs of this.
• There
  may be reinforcing plates in corners and across sections to reduce this
  happening. Check these for movement.

Greenhouse Interior

Check frame on the inside, including

• the fit of windows, louvres and doors
• how secure the window panes are in their frames – ie
  clips, putty, etc
• opening mechanisms –
  • manual , are all fittings in good repair, do they open
    and close easily?
  • automatic / powered – basic checks – loose screws, not
    working properly can be carried out; full inspections should be made by
    qualified personnel according to guidelines

Flooring

The maintenance required will depend non the material – tiles, concrete, etc.

However the basics for all include

• is it level?
• are there cracks?
• is standing water an issue? Check levels
• can water spillage easily drain away without causing a
  potential slip hazard?
• Are brooms etc easily reached to sweep away soil
  spillage etc

Heating

Depending on the type and scale of the system, annual checks by an engineer may be necessary. Basic checks, for example, the presence / not of cracks on visible pipes and trailing wires from an extra fan heater can be carried out as part of the general maintenance.

Even an unheated greenhouse may have insulation added on the inside. This may be attached by clips which may remain to support shading for the summer. Check they are firmly in place as they could form a trip hazard on walkways.

Electrics

Whilst checking if there are any obvious loose wires or switches is basic maintenance, electrical testing of supply and equipment should be carried out by a qualified electrician. This may be annual or tri-annual so the timing should be noted down and inspection booked.

Remember water and electricity do not mix. So leaving full watering cans next to live sockets on a pathway is probably not advisable…

Automated systems for ventilation, watering and heating will be maintained by qualified personnel. However, obvious items to include in basic checks would include –

• are vents and windows opening  / closing when they should?
• do the sprinklers spread more water on paths than
  plants?
• Does the temperature seem right / is the thermostat
  working properly

Staging, Shelves

As well as checking the tops for wear and tear, check underneath.

If it is a moving system on runners then all moving parts should be checked. One that is sticking may be doing so only because soil was dropped rather than anything more serious.

Other matters

There may be fire extinguishers and First aid box in the greenhouse. These should be checked as per requirements.

And then when everything has been checked, it needs to be cleaned, repaired or replaced as appropriate.  See the linked article.

Marie Shallcross  

Plews Garden Design and Consultancy

https://plewsgardendesign.co.uk/