Making the most of your Greenhouse by Nick Morgan

“Making the most of your Greenhouse”

Littleton and Harestock Gardening Club welcomed the return of Nick Morgan as the guest speaker in July to advise on greenhouses. Nick last spoke to the Club in 2009 and is a former Sparsholt College lecturer known to many Club members. He now acts in a senior glasshouse specialist advisor role at RHS Wisley, being one of only 2 such experts in the country. He was also heavily involved in the creation of the much acclaimed new glasshouse at Wisley.

Nick first distinguished between a glass house and a greenhouse as he accompanied his talk with a set of interesting sides. Glasshouses originated from commercial plant growing and greenhouses developed from orangeries.

He emphasised that the owner is IN CHARGE of the greenhouse and must make the decisions best suited to them on planting, heating, pests and cleaning. Clean glass in the spring is important to get the best light from the days. All greenhouses must have a cold frame facility of some sort, to allow new plants grown in the warmth of the greenhouse to be ‘hardened off’ before being exposed to open ground growing.

Location, location, location is an important factor in siting a new greenhouse and if conditions allow, the greenhouse should run east/west to make the most of months when daylight is at a premium. Heating policy is also a major factor in the life of a greenhouse. In an average winter in the South, it could cost as much as £280 to sustain 50 C minimum throughout the year. Thus ways of insulating and minimising the area to heat are all critical factors and the owner needs to decide what over wintering heat is affordable for them.

In the early spring, in order to get seeds/plants to thrive, they need heat to the roots. Sometimes just short bursts are required to germinate some seeds. As the outside temperatures warm up in spring and summer then shading, watering and feeding become the main focus. Nick demonstrated several options via his slides. If planting direct into soil is possible he stressed the need to sow thinly and ensure rows are well apart to enable good light to the plants as they grow. He advised peppers to be grown in pots, as the roots tend to keep warmer that way.

Nick then outlined common fruit problems such as split tomatoes (over watering), blossom end rot (too dry – particularly in grow bags), “cat face” – temperature changes and curled leaves – wind damage. Some plants need additional feeds such as magnesium (Epsom salts solution) when leaves go yellow. Mildew can be treated with baking soda. There are of course lots of pests such as white fly, aphids, red spider mite etc. Nick advised on treatments and prevention. With limited chemicals available these days, biological control is becoming more the norm. As time sped by Nick had to draw his talk to a close and kindly answered questions from the floor. Janet Hinxman offered a cheery vote of thanks and appreciation on behalf of the Club.