Just as is the case with greenhouses, there are also the same volume of pros and cons in owning a polytunnel. Whilst considerably cheaper than a greenhouse, you must take into account the investment, longevity and usage of whatever structure you decide to buy. These pieces of glass, or even polythene (depending upon the greenhouse or polytunnel) will in certain cases represent a considerable part of your gardening experience, as you enjoy watching your garden mature and flourish and as you develop your own garden over the short few months of each year through to the long-term years of maturity. It is therefore very important, as in a tremendous number of cases, that the type of cover for either the greenhouse or polytunnel will represent probably the largest outlay that you will have in your garden – and also represents one of the most important areas in your garden.
Yes, I know that there are various other important areas – particularly now that we are all going self-sufficient and have a variety of raised beds and are inter-mingling our vegetables with our flowers. Traditionally though, either the greenhouse or polytunnel represents not only one of the biggest outlays in your garden, but also one of the most important outlays as it converts part of your garden from the “ups and downs of the British weather” to a stable growing environment that you can yourself manipulate and make either hot or cold, wet or arid.
The Pros of owning a Polytunnel
1. When looking at the pros of the polytunnel, one must firstly reflect on its main competition – that being the greenhouse. Therefore, the biggest pro must be the cost. Polytunnels are so much cheaper than greenhouses. (Of course, not so much at the lower end of the market, where the relatively small greenhouses can be acquired with slightly flimsier products because they are more sheltered behind fences and therefore they are constructed in the same way as a polytunnel and can be quite flimsy). However for those areas where you require a structure of over, say 10ft in width and 12ft to 14ft in length, then the polytunnel becomes probably about 10 times cheaper than a greenhouse (when you add in the foundation construction that is required for a greenhouse)! Therefore, it must be considered as one of the main options as a garden structure.
2. Polytunnels tend to give a larger area for protected growing space than a greenhouse. It also provides an element of flexibility in that, quite frankly glass does not bend, but polythene does, and is therefore more forgiving if you have a slightly out of control plant.
3. There is considerably more flexibility in owning a polytunnel in that you can have doors widened to fit certain machinery that you may want to install in the polytunnel at any given chance, or just for the daily moving in and out of wheelbarrows for compost etc.
4. Polytunnels are also very forgiving, particularly on those who are slightly larger than normal and if you require some more height, as they tend (with their structure design) to be built in a way that makes you able to walk around them almost up to the edges freely. Whereas with greenhouses, the eaves tend to drop suddenly and therefore you are squatting, certainly as you near the glass.
5. There is a wide choice of design equipment, where you can choose the fabric of your construction both in terms of the size of aluminium posting that you require and also the polythene that you wish to cover your construction with and whether that is to include some sort of ventilation or netting. You can also adapt your polytunnel, if you like, into a mini fruit cage – as many people do.
6. Running on from the previous point, you do not necessarily need to use a polytunnel for enclosing in polythene. You could use it as a large fruit tent, which can be equally as productive as if you were growing any other type of product in it.
7. Polytunnel manufacturers have now become smarter, in that they are using the greenhouse manufacturers’ internal products to give flexibility to those people wishing to own a polytunnel. They now offer a variety of staging implements, irrigation systems and matting, all of which complements and assists in perfecting your growing area, and how you want it to be designed specifically.
8. For those people who like some degree of peace of mind, there is also a variety of additional elements that you can add to your structure that provides rigidity, such as wind bars, depending upon the site that you want to place your polytunnel.
9. After price (and this is the last point I use) one of the real bonus areas for polytunnels is if you do have concerns with operating a system which has glass, which a majority of greenhouses do (well the correct ones do – the rest have a polyethylene sheeting which, if you have ever owned a greenhouse with polyethylene sheeting, you will know that in a strong wind you have provided a neighbour’s great amusement at watching bits of plastic fly around your garden). However with a poytunnel you have a large sheet of plastic. If, for some reason, this gets damaged or torn in particularly difficult weather, then either you can tape the patch up or if you lose the polytunnel plastic, you can replace the polytunnel cover. There is no long-term damage, there are no accidents or cuts and it is a simple, effective solution that does not affect the most expensive part of the structure of the growing area. If you lose a pane of glass however, and the wind gets inside that small area, it can blow the rest of the glass. This can cost considerable amounts of money in the clear-up, and potential dangers of having broken glass are considerable.
The Cons of owning a Polytunnel
1. The most important con of owning a polytunnel is that it does not look as nice as a greenhouse. Yes, they have come on leaps and bounds and yes, they do offer numerous advantages and are not as aesthetically challenging as they used to be – but ultimately they are structures with a large lump of polythene wrapped around them. They can only look so good and cannot really be adapted, as a greenhouse can, to become a truly beautiful structure in your garden.
2. Polytunnel covers can degrade over time. It is said that the shelf-life is about 5 to 6 years. However, this can of course be outweighed by not having to clean them every year, as you do with a greenhouse. Ultimately, there is nothing wrong with freshening up a polytunnel every 5 or 6 years, particularly now that they do offer a system which means that instead of digging a large trench around the polytunnel structure, you can actually clip in the fabric at the bottom, which saves a huge amount of man hours.
3. It was listed in the Pros section, but of course – it will also have to be listed in the negative section as well, in that if a pane of glass does get smashed in a greenhouse, then you simply replace that pane of glass. However, if the polytunnel is ripped and torn and you do not have sufficient tape to cover the situation because the tear is so great, then potentially you will need to replace the whole of the polytunnel material. Whilst this is not overly expensive, it is time-consuming and is not as straightforward as simply replacing a pane of glass.
4. Polytunnels do not offer the same “almost luxurious” medium for growing. You do not generally skip up the garden – as you would on a cold winter’s day, with paraffin blowing into a nice Victorian greenhouse to while away the hours, move all your seeds around, tidy and clean up. The polytunnel is more a “functional beast” – where it tends to be hidden in a vegetable patch and is there out of the ability to utilise, rather than the ability to show off.
In all the pros and cons for the polytunnel, as with anything, ultimately I think it all comes down to price. If you are buying any form of structure that requires an area which is greater than the size of a postage stamp, then the polytunnel is the right choice. It provides flexibility, ease of construction and a wonderful chance for a product to be grown. The polythene covering seems to work better than greenhouse glass, unless of course you have glass tinted or white-washed, in which case you are spending more man hours doing that, and you are potentially ruining the structure’s looks if you do this. Lastly, but no means least, the cost of a polytunnel against that of a greenhouse including the setting up of a greenhouse’s base construction is so great that, unless you fortunately have a huge amount of money, or you really do want a greenhouse and you have a huge investment that you want to make it into, then a polytunnel is the only choice you should make.
I have always, through my research, looked at trying to spend a bit more on a polytunnel – not so much to show off, but to provide a structure that really does work and provides you with the greatest chance of making your produce work for you, which gives you the best environment as well. Therefore, the larger polytunnels with the greater width spans, larger aluminium poles and various braces and irrigation systems (whilst only costing an extra couple of hundred pounds) can make a whole world of difference.