Considering A Greenhouse
Imagine being able to leave the fog and the frost, the drizzle and the depressing dreariness of an Irish winter behind and set up a garden on a sub-tropical isle!
Just think of being able to have a predictable climate for once, where one warm day follows another and the depressions which sweep in from the Atlantic were something to pray for rather than curse! Paradise? Wishful thinking? Perhaps, yet for many, the dream has already arrived as those with even the most modest of glasshouses will testify!
What to Grow
In a greenhouse you can grow exotic plants such as alpines from Mexico, orchids, cacti, expensive and out of season fruits and an ever changing selection of pot plants for indoor decoration. You can grow Christmas-flowering chrysanthemums, or specialise in carnations or fuchsias, bring to perfection a huge variety of spring bulbs in pots and containers, or grow as many annuals from seed as you are ever likely to use. There’s the attraction of being able to grow fresh lettuce in winter; cucumbers, tomatoes, peppers and melons in summer; and give vegetables like cauliflowers a good start to life before transplanting them outside in late spring.
Equipment
You can’t go wrong nowadays for there’s a huge range of modern greenhouses and greenhouse equipment available at affordable prices. For instance, there are heaters of every kind (ranging from electric through to gas and paraffin), electric soil-warming cables, automatic door and vent openers, cooling fans, misting units, capillary matting for watering when no-one is at home, self-adjusting blinds to keep out the sun during the hottest part of the day, even detectors to warn of intruders like vermin.
Benches and staging for greenhouses are of a standard height (81cm high by 45cm deep), constructed of aluminium and sold commercially in all large garden centres. These are rot and rust proof and last a lifetime.
Climate control
To produce healthier plants, the climate in a greenhouse can be controlled through a combination of ventilation, shading, misting and heating. A maximum/minimum thermometer will tell you when to open or close vents and when to cover tender plants from damaging early or late frosts. An automated climate control system can be installed at very little cost. The device works on the presumption that optimum plant growth is achieved between 10 and 30 degrees centigrade, and automatically
opens and closes windows/vents as required.
Shading can be obtained by painting the glass on the outside with a special white paint which reduces the level of sunlight penetrating into the greenhouse. Brush it on as the season begins to heat up and wipe it off in September. Rain, however, will not wash it off. Care should be taken to use the minimum amount of shading, as excessive reduction in light could impair plant growth. Temperatures can be reduced further by misting: spraying the greenhouse with fine droplets of water.
Types of Greenhouse
There are four kinds of greenhouse which can make all these things possible. They are known as cold, cool, warm or hot houses according to how much heat, if any, is provided. Most will settle for a cold greenhouse, one with no heating, for it is ideal for growing all kinds of plants right throughout the Irish winter. If contemplating a greenhouse then, get the biggest you can afford. You’ll fill it in a single season and wish it was double the size. Buy a free-standing model or lean-to, one in aluminium or wood, glass to ground or one with a brick base, but go out and buy one.
Watering
Keeping the compost dry (or almost dry) during the long dark months means you will successfully over-winter just about everything and be first away in spring with the new seasons plants. Plants should not be allowed to dry out during the summer months. Watering can be accomplished manually using a watering can or hose, or using a simple irrigation system which is easy to install and use. Capillary matting is available in most garden centres and is very effective in maintaining optimum moisture levels.
Flooring
As to flooring, an option is to pave this with 45cm x 45cm patio slabs or similar, rather than concrete the lot, for they can be lifted and re-laid easily and in any number of ways if the need arises. It may only be necessary to install a central aisle rather than cover the entire floor surface. For an aisle of bricks: line the walkway with 5 x 10cm treated timber, put down 5cm of crushed rock or gravel and cover with 2.5cm of sand, lay the bricks with 1cm spacing and fill in with sand. Finish the remainder of the floor with 5cm of gravel.
Heating
When it comes to providing just a modicum of heat in spring, rely on a fan heater which is thermostatically controlled to produce just enough heat to ward off night-time frosts. The unit is small, reliable, maintenance-free and efficient. Because of the low temperature settings the expense is minimal. Parafin heaters and heated propagators are also available but require more maintenance.
Lighting
Lighting may be supplemented in a greenhouse in order to extend the day length and achieve optimum plant growth. By shading plants with a dark fabric you can reduce the number of light hours (photo period) in order to ‘force’ flowering of particular species such as, poinsettias or chrysanthemums.
Growing media
Depending on what you want to grow there is a wide selection of soil and soil-less media mixes that can be purchased in your garden centre. You may also decide to make up your own mixes. Ready to use ‘Growbags’, where the plants are grown directly in the bag, have become very popular and are very effective. Yes, there’s is something immensely enjoyable about working in a greenhouse when the days are cold, wet and miserable.
Bord Bia It’s Garden Time
With thanks to Bord Bia for this article. For more information on Bord Bia and for further gardening tips and advice, visit http://www.bordbia.ie/consumer/gardening/itsgardentime/pages/gardentips.aspx