CROPS, METHODS, MANAGEMENT 45 



sitates well arranged and efficient heating apparatus, 

 suitable fuel, and skilful stoking. Extremes and sudden 

 alternations of high and low temperatures should always 

 be avoided. Plants seriously checked in leaf, growth, 

 flower, or fruit development are often permanently 

 injured, and their value, or that of the produce, greatly 

 reduced. 



2. Ventilation. Adequate and easily worked means 

 of ventilation is important. A gradual increase of 

 ventilation is a safe way of decreasing temperature, and 

 hardening plants for sale or use. Aeration is also 

 necessary to the welfare of many plants. Excessive 

 ventilation in highly heated houses is one of the causes 

 of injurious checks noted in the preceding paragraph. 



3. Supplies of Water. A skilful gardener must have 

 mastered the use of the water-can. It is an essential 

 portion of his art in under-glass work. Plants grown 

 in glass-houses are subjected to rapid evaporation, and 

 those in pots have limited soil stores of moisture to draw 

 upon. Constant attention is therefore requisite to keep 

 the balance. In an atmosphere saturated with moisture 

 the evaporation is proportionately reduced, but while 

 essential to some plants that condition would be fatal 

 to others, though between the extremes there are many 

 stages that are helpful in preserving plant-health. 



4. Sun-light and Sun-heat. To benefit to the fullest 

 extent by these influences early in the season, wide 

 glass sheets, the reduction of rafters to the minimum 

 consistent with stability, and a sharply angled roof 

 facing south are essential. To these may be added the 

 necessity for keeping the glass clean, both inside and 

 outside the house, the latter being of urgent importance 

 in town districts where the deposits from smoke-laden 

 air are abundant. 



Insects and diseases are mentioned in preceding 

 paragraphs. 



