Greenhouses

Polytunnels & Frost Protection.

Our 4.5m wide model left out in the cold.

Polytunnels like other greenhouses provides protection for crops over the colder winter months. The biggest threat to plants during this colder period is frost.

Frost causes the water in plant cells to freeze. The result of this is damage to the cell wall which leads to wilted growth causing the plant to become blackened and distorted.

Under sever frost the temperature will drop to a point where only supplementary heating inside the tunnel will protect against the cold.

But before reaching this point, there are some steps that maximise your tunnels ability to protect against the frost.

Make sure your tunnel is located in the sunniest location of the garden. This allows your tunnel to heat up during the day in the low winter sun.

Clean your tunnel cover annually. This will reduced any obstructions to the sunlight passing through the polythene which will also help heat the tunnel.

Finally make sure when purchasing your tunnel than you only use a thermic plastic, which has good thermal properties. This will help reduce heat loss through the cover thus giving better protection to your crops during winter.

Thankfully its nicer inside than outside the tunnel.

Community Gardens

Recently I saw an article in the Sunday Times written by Gabrielle Monaghan. It was great to read something more positive than the normal doom and gloom that is seen in our daily media reports thanks to our current economic crisis.

Gabrielle wrote about the Mount street club Trust. It origins and how it contributes to building and improving our community.

The Mount Street Club was established in Dublin in 1934. Its aim at the time was to give the unemployed the chance to work in return for food. As our state improved and social services increased unfortunately the mount street club services became more and more redundant.

However more recently the mount street trust has put forward new incentives to help tackle current difficulties in our communities. It now hopes to offer the employed an opportunity to get involved in growing their own again. They hope to do this through allotments and community gardens as part of €330,000 project.

The mount street club trust is using money from the 2006 sale of its former headquarters to fund the project. They are offering up to €10,000 in grants. Community gardens have been invited to apply if they involve the unemployed in the planting, growing and harvesting of food.

As part of the new scheme, gardening experts from Grow it Yourself (GIY) a charity established last year will provide groups with access to unused land or local authority plots. The fund is being distributed be the community foundation for Ireland.

Corrigan Cooks Naturally


Grow your own has enjoyed a new lease of life over the past few years. Now more than ever people are turning back to their gardens, small holdings and whatever free space they can find to try their hand at growing their own.

For those who are looking for some inspiration to get them started then I strongly suggest having a look at a television series currently running on RTE 1. It is hosted by celebrity chef Richard Corrigan and it’s called Corrigan Cooks Naturally. His mottos are Taste Local and celebrate what’s local, what’s good and ultimately what’s natural.

This year he has his own Corrigan Cooks Naturally Roadshow and he’s bringing it all around the country. He has recruited a few experts to give him a hand. Vivienne Campbell medical herbalist who can show you how plants and flowers can make remedies and even natural beauty products. Along with her is horticulturalist Kitty Scully who wants us all to reconnect with our food heritage.

I have to give it to them; it’s a great show and gets the mind going. As well as the fantastic ideas that can be gotten from the show you will also find great recipes that gets the taste buds tingling. So it one to watch. It’s on Wednesdays 20.30 – 21.00.

Siting your Greenhouse

A sunny position is most important for plants to grow well. For strength you must point the gable end towards the prevailing wind. If there is a slight slope on the site you should run the length of the Polydome down the slope (apart from structural reasons this will help ventilation). You need to allow room all around the Polydome for digging trenches and avoiding snagging the cover on things, if we are constructing we ask for about 1.5m on either side of the Polydome and 2m at either end if possible. You should have some shelter from prevailing winds using trees or windbreak net which will filter the wind. You should avoid choosing a stony, boggy or very sloping site if possible as it requires extra materials and work to build.

Polydome Blog

Hello All,

Welcome to Polydome’s new blog. We are delighted to be finally online.

Over the coming months we hope to use this source as a means to sharing with you our experience in the greenhouse industry. Over the past 25 years Polydome has become one of the largest suppliers of hobby polytunnels and glasshouses within Ireland. We now hope to pass on some of the knowledge and expertise we have gained over the years. We hope this information will help anyone making the next step in purchasing or making their own greenhouse.

So watch this space.

Irrigation In Polytunnels

The majority of vegetables are 80 to 95 percent water. So next time you look at your lovely vegetables in your tunnel or glasshouse think of them as little sacks of water, flavoured and full of vitamins.

But remember, if the supply of water fails your vegetables yield and quality will suffer rapidly. In the high temperatures found in polytunnels and glasshouses it’s very important to irrigate on a regular basis and guarantee a reliable supply.

The two most common methods of irrigation are overhead irrigation and ground level irrigation. Overhead is by far the simplest method. Water is released from sprinklers suspended from the roof of the tunnel or the glasshouse. These form a mist which saturates everything in the tunnel.

Some draw backs of overhead irrigation: water is wasted as it not only falls on the beds and plants, but also the walkways through your greenhouse as well as work areas: sun spots are more likely to occur as the result of droplets forming on the foliage: and a large number of plants prefer being watered into the root as appose to directly onto the plant itself.

Ground irrigation is a much more effective method. Lines of perforated pipe lay on top of the vegetables beds. Built in regulators in the perforated pipe leak out a set amount of water per hour. This allows even irrigation across the bed and more importantly directly into the root.

However it does have its drawbacks also. More pipes + more fitting = higher costs. Also, as the pipes sit on top of the beds they sometimes can be in the way during weeding and planting.

Don’t forget to automate your irrigation system if you’re away for long periods, therefore guaranteeing that your plants get their daily dose. Tap timers are a simple and effective solution. These can be gotten in many garden centres and DIY shops and are very easy to install.

If you require further information feel free to visit our website.

The picture on the left is of an overhead spray line. The picture on the right is drip irrigation.

The Urban Garden

Over recent years “grow your own” received a new lease of life, and many have the idea of growing their own fruit and veg. For people living in the countryside the space needed to do this has not been an issue. But for those in the urban environment lack of space can pose many problems. Nevertheless this shouldn’t be a limiting factor.

You can choose different varieties of fruit and veg that are bred to grow in small spaces. If they have the words patio, pixie, tiny, baby or dwarf in their name it is a good bet. Remember plants that are bred to be small doesn’t mean the fruits will be small or the yield less. Normally by looking on the seedling pack it will tell you the mature size of the plants you are selecting. You can then decide which suits your space best.

Vegetables need a good 6 or more hours of sun each day. Without sun, the fruits will not ripen and the plants will be stressed. Some crops that can survive in light shade are lettuce, broccoli and other cole crops. For those who have shaded balconies or north facing apartments it’s important to give good consideration to crop selection as lack of sunlight could be an issue.

For those who always wanted their own greenhouse but thought they didn’t have the room you will be glad to know must manufacturers cater for this end of the market. And as they are small, they are also very affordable. Some examples are the Eden/Halls lean-to (2 ft x 4 ft model). and the Elite window garden.  

So maximize your limited space, carefully select your crop and enjoy the pleasures of happy growing……

Polytunnels vs. Glasshouses

For those taking the next step and investing in a greenhouse, it can be sometimes hard to find which option suits best. My advice is to find a greenhouse that compliments your garden while also being practical for its intended use.

Firstly you should avoid generalising about characteristics of Polytunnels vs Glasshouses (e.g. thinking Polytunnels are stronger than Glasshouses or Vice Versa).  There are a huge range of Polytunnels from extremely strong to extremely flimsy and the same applies to Glasshouses.  One generalisation one can usually make is that  something very cheap is probably very flimsy, and usually to have something strong is going to cost more that something weak. 

Sometimes customers ask which is better for growing plants – a Polytunnel or a Glasshouse, but if adequate ventilation is provided (and that depends on the features or model you choose) then the growing conditions are much the same.

Ultimately this debate boils down to personal choice, so instead of given my opinion on which I think is best I have listed below some pros and cons of both Polytunnels and Glasshouses. I hope this makes your search that bit easier…..

Polytunnel Pros

If you are looking for something quite large, the difference in cost between a Polytunnel and a Glasshouse is quite substantial.  Vegetables particularly take up a lot of space, so a Polytunnel will give you a larger area of protected space to grow for your money than a Glasshouse – all things in terms of strength and ventilation being equal.

There is more flexibility to customize your structure to suit unusual needs. i.e. widening the doors for machinery or coping with sloping ground, a Polytunnel is much more easily modified than a Glasshouse.

Straight sided tunnels provide a very pleasant working area internally as a result of the height. If your 6’ 2” like me, this is an added plus. It also means taller crops are less likely to be touching off the polythene cover.

Polytunnel Cons

Although Polytunnel Covers are UV stabilised to give long life, they do need to be replaced periodically (depending on the grade chosen usually every 4 or 5 years, but some customers getting much longer – it depends on many factors such as how much sunlight the cover get.   With larger structures this can be a bit of a headache, it requires the customer to think ahead and test the polythene when coming up to its expected end of life so to anticipate when to recover it rather than having the cover fail in the middle of a period of inclement weather.

Polytunnels can prove slightly harder to construct as it involves holding a large sheet of polythene, so any wind at all makes covering tricky. Tensioning the polythene to the adequate tension is a developed skill. It is very achievable by all but takes patience and planning when covering ones tunnel for the first time

In a glasshouse if you break a pane of glass you can replace that pane. Do the same with Polytunnels cover and you have to try and tape it (not the best or most permanent job). In the worse case situation you might even have to recover the full tunnel if needs be.

Prone to attack by cats and dogs (and birds pecking at insects at the ridge). Not the most common of problems however I have heard of it occurring on more than a few occasions. Therefore worth noting if you have pets around.

Polytunnels are not an item of beauty to most, so generally people want to keep them out of sight in the vegetable plot.

At present there are not as many options for ventilation in Hobby Polytunnels as there are for Glasshouses.  Ventilation is usually only supplied by opening doors at both ends whereas a Glasshouse can have roof vents, louvre vents and these can easily be fitted with automatic opening devices which do not need electricity to work.

Glasshouse Pros

 
Glasshouses are available in very attractive designs that compliment a garden, such as Orangeries, Victorian style Models and Dwarf Wall Greenhouses, with the frames being available in a range of colours.  They do not need to be kept out of sight so can be situated nearer your house and this can be an advantage in terms of making use of it.

Glasshouses will need periodic cleaning as do Polytunnels but you don’t need to replace the covers every few years.

Aluminum has a very long lifespan and powder coated models protect the aluminium from oxidising and so retain the good looks of the Greenhouse for longer.

Glasshouses are available with a wider range of ventilation options  than Polytunnels and also there is an abundance of shelving and other accessories for them that are not widely available for Polytunnels.  For example rainwater collection from a Glasshouse is simple as they nearly all have built in gutters, it is just a question of ordering downpipes and a water barrel for it. 

Glasshouse Cons

A flat and level base is required for a Glasshouse, so generally speaking the preparation of the site is a bigger job than a Polytunnel.

The lead time for supplying some Glasshouses can be up to 3 months, so you need to plan ahead  (unless it’s a standard model, these are normally in stock by glasshouse suppliers).  Most Polytunnels that are produced in Ireland can be manufactured within days of order.

To summarise

Joking apart, many customers get both a Polytunnel and a Glasshouse.  The Polytunnel is at home in the vegetable patch out of sight, doing a fantastic job of protecting the vegetables from excess rain and wind, providing excellent growing conditions, the Glasshouse up near the house, a feature in the garden and used for propagation, flowers, bedding plants and perhaps a few tomatoes.  So the question does not have to be Polytunnel or Glasshouse, it can be which Polytunnel and which Glasshouse (probably not all at once).

Grow your own

Grow your own

The difference will amaze you. Free from the ravages of the weather you can create ideal growing conditions for all sorts of vegetables and flowers in a Polytunnel or glasshouse, avoiding the frustrations of growing outdoors. No more plants being drowned by torrential rain, frozen and battered by the wind.

In a Polytunnel or glasshouse you will enjoy an extended growing season, being able to plant earlier in the season with less risk of frost (and even earlier again if you use a frost protection heater) and enjoy plant growth longer than is possible outdoors.

If you are new to growing you will be able to enjoy producing healthy organic crops and if new to growing your own vegetables you are in for a surprise as the taste of fresh vegetables picked and eaten the same day is really fantastic.

Lastly, if you have found Murphy’s law to be true that whenever you have a day off to escape to the quiet of the garden and the weather is most likely to be awful, with a Polydome Greenhouse your personal space will be available to you year round to forget about work and enjoy your hobby no matter what way the weather is.