Subscribe to this blog

Subscribe to full feed RSS
What the? RSS?!

Subscribe Via Email

We respect your privacy.
Archive for the ‘Greenhouse Gardening’ Category

Insulation Of Your Greenhouse

By admin On October 31, 2008 No Comments

Conserving heat is essential, especially if the greenhouse is used in winter. Bubble glazing, formed of three layers of plastic with air-bubbles between them, traps warmth within the greenhouse and is especially valuable for attaching to the coldest and most exposed sides and roof. It is held in place by a range of fittings, including double-sided adhesive pads, drawing pins in wooden greenhouses and special clips in aluminium types.

Both white and green ‘bubble’ insulation is available: the green often makes the greenhouse too dark in winter, although if left in place in summer it creates useful shade. Other forms of isolative material include polythene sheets reinforced with wire mesh.

Large greenhouses can be mad more economic to heat by partitioning them with these materials, but ensure they are firmly secured and cannot fall on top of a heater.


Greenhouses Optimum Temperature

By admin On October 31, 2008 No Comments

Clearly, the way to save money on heating is to have a ‘cold house’ and not provide any warmth – but this restricts the range of plants.

If the heating is limited to ensuring the temperature never falls below 7°C /45°F, this is called a ‘cool house’ and enables a wider range of plants to be grown

Keeping the temperature at 16°C/61°F or more throughout the year enables tropical plants to be grown, but the cost is high.

An agreeable temperature compromise – and one that saves money – is just to heat the greenhouse in late winter and spring, when sowing seeds and raising young plants; and in summer to grow plants such as tomatoes that benefit from the protection afforded by unheated greenhouse.

Using an electric or paraffin heated propagator in late winter and early spring to encourage seed germination and the rooting of cuttings saves having to heat the entire greenhouse and reduces heating costs dramatically.


Positioning Your Greenhouse

By admin On October 31, 2008 No Comments

Orientate full-span greenhouses so that the ridge runs from east to west. This enables low, winter light to pass through the glass.

Additionally, if tall plants are positioned on the side away from the sun they do not cast cooling shadows over others.

Avoid places shaded by buildings or trees, as well as overhanging trees that might drip rain on the greenhouse.

Position the door away from prevailing winds. Most doors in metal-framed greenhouses are on runners and slide across the opening, but wooden types are hinged, if possible, so that they open away from the prevailing wind.

A hedge on the windward side helps to reduce wind speed and therefore its cooling effect. Indeed, the benefit of a hedge can be felt up to a distance of thirty times its height. For instance, a hedge 2.4m/8ft high reduces the wind’s speed by 75% at a point 4.5m/15ft from it. And at a distance of 12m/40ft the reduction is still as much as 65%

Lean-to greenhouses require warm walls, especially to encourage the development of early maturing crops


Greenhouse Heat Loss

By admin On October 31, 2008 No Comments

Heating is a major cost factor in running a greenhouse and any way to reduce this is worth pursuing. Indeed, a wind exposed situation or a frost-pocket could double the expense of heating a greenhouse during winter.

There are several ways to decrease the costs: correctly positioning the greenhouse, installing insulation, and carefully controlling the temperature.


Managing A Greenhouse

By admin On October 13, 2008 No Comments

Ventilation of a greenhouse is of great importance and is the key to healthy plant growth in any greenhouse. Fresh air is essential and the use of ventilators also regulates the temperature which is especially important in summer.

For every 1.8 - 2.4m (6-9ft) length of greenhouse there should be at least one top roof ventilator and one at the side low down, preferably more. On windy days the ventilators should be opened on the side away from prevailing wind. In winter the one at the top should be open just a crack unless severely cold.

Ventilators can be hand operated, electronically or chemically operated and all options are fairly inexpensive.

The atmosphere should never be stuffy or unduly humid (except for special plants such as cucumbers). However, draughts should be avoided.

With correct ventilation, humidity will also be at the right level without being excessive (meters for measuring humidity are available). In hot dry weather humidity should be maintained by damping down the greenhouse two or three times a day, the last time by mid afternoon.

Maximum light is essential in winter, spring and autumn. The glazing should be kept clean and free of leaves and other debris. In summer, shading will be necessary with washes or blinds. In winter, plastic sheet used as double glazing will unavoidably reduce the available light but there is now an anti-condensation sheet available.

Very high temperatures are not suitable. Most plants are happy with a range between 7 and 33 degrees C, depending on whether they are temperate or sub tropical plants. In winter various forms of heating can be used: oil, electricity, solid fuel or gas. A maximum and minimum thermometer will be very useful, particularly for recording minimum night temperatures.

Hygiene and cleanliness are vital. The inside of the greenhouse: staging, floor (if concrete or paved) and equipment should be cleaned with a sterilizing solution once a year. Fallen vegetation should be removed, badly diseased or pest ridden plants destroyed and the house kept free from piles of dirty pots, seed trays, labels, canes, crocks and other clutter. Try to keep the maximum amount of space available for growing plants.