Ask the experts

As a family we have been manufacturing greenhouses for over 80 years and the accumulated expertise has been hand down the generations. In our conversations with customers there are some questions that occur more often than others. If you would like to discuss your requirements over the telephone or on a site visit then please telephone on 01892 750247.

Q. Where do I put a greenhouse?
A. Keep it in view and make it a feature of your garden. Access is important. If the greenhouse is where you will visit the plants regularly the plants get better care and therefore grow better than in a greenhouse hidden away and forgotten. In a small garden it is important that the greenhouse looks attractive and can then be put in full view. If you can see that the plants need your attention they will do better and give more pleasure.
Having the greenhouse near the house also makes it easier to visit. If you have to brave a journey through wind and rain you are less likely to visit your plants than if it is a quick nip out of the door. This also makes it easier to install services such as water and electricity.

A hexalight greenhouse over looking a golf course

Q. Should the greenhouse be in full sunshine?
A. No. Try to find some shade. Plants need light to grow but too much light can be as big a problem as too little. Putting a greenhouse in the middle of a lawn where it received full sunlight all day long is not the best option. It is use any natural shade in the garden to reduce the light and heat at the hottest times of day.
Given the choice the plants will do best if they get the morning sun. In the morning there is water vapour in the air, this filters out some of the harmful UV wavelengths. The evening sun does far more damage to tissues than the morning sun. The sun at midday is the hottest part of the day and is coming in at a high angle making it easier to shade against. The low evening sun can be as hot and also drier. Plants tissues can be burnt by the sun in the same way that we suffer sunburn.

“Hexalight” Alpine House using natural shade

Q. What is the best direction for a greenhouse to face?
A. In our experience this is not important. With a ridge greenhouse such as the "General Purpose" Greenhouse or "Extendible Unit" greenhouse and the “Span Roof” Brick Base Greenhouses the ridge could run North/South or East/West. The old gardening books differed in their advice. Some advise that the ridge should be East/West to catch the maximum summer sun but others say run the ridge North / South to make the best of the morning sun and have the maximum shading from the framing of the greenhouse. In most gardens there is little choice and it is better to fit the greenhouse to the design of the garden.
In a long thin garden the greenhouse can be used to emphasise the length of the garden or to divide the garden into areas of cultivation. The "Hexalight" and “Quadlight” Greenhouses have no main axis and this makes it easier to fit into your garden design.If you have no other constraints then the morning sun is best for the plants and the evening sun should be avoided.

Q. Do I need planning permissions?
A. This is a question that may need local advice. If the greenhouse is small (below 10cubm) and far from your boundary or to replace an existing building then planning is not usually required. If you are in a listed property or in a conservation area then different rules apply.
Our advice is that for a small greenhouse more than a metre from the boundary then planning is not usually needed. For larger buildings or Lean-To Greenhouses against the property or a Lean-To Greenhouse or Unequal Span using a boundary wall you should take local advice.

Q. Which is the best material for a greenhouse, timber, Aluminium
or plastic?
A. Our answer to this is that Western Red Cedar is the best for the plants and the garden and the environment. The only energy that was used in making the timber was solar power. The advantage of timber is that it is a poor conductor of heat, in winter this reduces heat loss and in summer this keeps the greenhouse form warming up to quickly. On a summers night the heat built up in the day will keep the plants warm through the night. This will provide a stable environment for your plants.
Other advantages of Western Red Cedar are that it is tough and will give in strong winds rather than break, if a pane of glass breaks you can do your own replacement without special fixings and any fittings such as shelves do not need special fixings. There is a down side to wood, especially soft wood. Soft woods such as Deal will need painting and preservatives and do not have a long life but Western Red Cedar is naturally rot resistant. Preservatives will protect the wood but can be detrimental to the health of your plants and the environment. Western Red Cedar should last over 40 years with only and annual wash. We have many greenhouses still in use after more than 50years.

Q. What is the best glazing material for a greenhouse?
A. Glass gives better light transmission than other materials and is better for your plants. If you have worries over safety we can advise alternative glazing. Polycarbonate gives better insulation and may be used where heat retention is a priority but it deteriorates over time.

Q. Do I need to heat my greenhouse?
A. You can grow a whole range of plants in the protected environment of a greenhouse without any heating. A timber greenhouse will be better insulated than a metal greenhouse and will therefore have less need for heat. An unheated greenhouse can be used for over wintering some plants and also to bring other crops on early in the spring. Don’t waste heat by having draughty doors or poorly fitted glass. For some plants the main danger to them is winter rain causing the plant to rot while the plant is dormant and for these a cold greenhouse is sufficient.
You do not need heat but you can extend the range of what you can do with even a little heat. Speak to us about the right choice of heating for your plants.

Q. How do I keep my greenhouse cool in summer?
A. This has become more of a problem as the summers warm up. The answer here comes in stages, Firstly make sure the greenhouse is sited out of the full afternoon sun. Then buy a greenhouse that is not all glass. (If it is all glass use an opaque material such as polystyrene panels to blank out some of the glazing at floor level.) Make sure the greenhouse you buy has good ventilation. The hot air needs to exit at the ridge and cool air come in as low as possible. Keep the soil in the greenhouse exposed and not a dry concrete soil cover. Keep the plants well watered and the soil damped down. Trays of water or wet gravel help. Plants can cope with heat if they have sufficient water to keep themselves cool so watch the plants not the thermometer.
It is only at this stage that you need to consider shading. Some plants are more sensitive than other and so will need denser shade. Shading on the outside of the greenhouse is more beneficial than on the inside as it blocks the heat before it gets into the greenhouse. There is a section on our Accessories page on types of shading.

Q. Does a Western Red Cedar greenhouse need lots of maintenance?
A. No. If the timber is good quality Western Red Cedar it needs no maintenance. Left untreated it should last you 40 or more years. The natural oils in Western Red Cedar act as a natural preservative and act best if the timber can breathe. Putting "preservative" such as "Cuprinol" onto Western Red Cedar will seal the surface and stop the natural oils form working, The timber will then rot from the inside out. All timber treatments produce “fumes” that can be detrimental to sensitive plants.
Any greenhouse needs an annual or twice yearly wash to let the light in through the glass. When washing the glass in a Western Red Cedar Greenhouse wash the timber at the same time.

Q. How can I use my greenhouse all year round?
A. If you start with a greenhouse designed for general growing with not too much glass and a well insulated timber frame you can have your greenhouse in use for 12 months a year. This may need careful planning and some years the weather will upset your plans. (See our advice on heating).
At the start of the year you will have in the greenhouse over wintering plants (perhaps under the staging). In early spring start to plant your seeds. You may find that a "Propagator" or heated propagating tray may help to start germination off. As the seedlings grow they will need to be pricked out. This is the time of year when capacity becomes a problem. Your seedlings need space and the weather is not right yet. Extra shelves can help and you may find in time that you need a Garden Frame to increase your protected space. When the seedlings are out you can now start growing on your more tender indoor crops such as Peppers and Chillies even Tomatoes. You could also start growing your own winter flowering houseplants. Poor Mans Orchid makes and attractive and unusual house plant.
When the summer is over and your indoor crops are harvested you will need to start bringing tender plants in for winter shelter. You should also consider continuing your sheltered growing by sowing salad crops in the greenhouse in autumn for winter harvesting. Fresh young carrots for Christmas will complete your greenhouse's year.

A protected environment		Early Strawberries

Q. How big a greenhouse do I need?
A. "A greenhouse is never too big" is advice from older more experienced gardeners. (Other things that are never too are a kitchen, a freezer and a bank balance.)
Plan the size in proportion to the garden and what you plan to grow. Will the building look large or will it blend? This can best be decided by marking out the corners with canes. What will you be growing? If you are a large garden and an allotment you will have times in the spring and in the autumn when you will need more space however big the greenhouse. When you have an idea of what you could grow plan that out as seed trays of plants. How many seed trays will you have once you have pricked out your germinated seeds? A seed tray is 355mmx230mm (14x9inches).

Q. Do I need a special greenhouse for some plants?
A. Yes. To grow a successful crop of grapes the Vine needs a house to itself. The Vine does best if it is cold and draughty in its dormant period in January and February. (When most greenhouses are warmed up for the start of propagating.) It may be possible to share the Vine House with seedlings once they are pricked out and before they go into the garden or with a crop of Tomatoes or Peppers in the summer months but the dense shade of the Vine may make this difficult.
A collection of Alpines needs to be cool and windy but you could start with a plunge tray by an open window. For more information follow the links to Alpine Houses.
Orchids from cool habitats will share with other plants. Tropical Orchids will need a controlled environment all of their own. For more information follow the links to Orchid Houses.
If you specialise you will find that many other groups of plants need special environments. We can design a greenhouse to produce these special environments. We are always happy to discuss the needs of particular plant collections (telephone 01892 750247).

Q. I have a very awkward site can you help with siting the greenhouse?
A. Yes. Please telephone (01892 750247) for further advice and if necessary we can arrange to visit. We may be able to offer help and advice if you email us with some pictures of the garden.

Left: A mountain side greenhouse Right: Bridging a garage