FLOWER POT COMPOSITION AND ITS EFFECT 

 ON PLANT GROWTH 



By Linus H. Jones,' Assistant Research Professor of Botany 



Introduction 



An investigation of the merits of several types of phint containers has 

 revealed some interesting problems, the solution of which is of value to both 

 the producers and users of flower pots. The standard porous clay pot, with 

 drainage hole in the bottom, is in general use wherever plants are grown in 

 containers. With a good potting soil, proper temperature, water, and suffi- 

 cient light, the attendant in a greenhouse knows he can produce good plants in 

 such pots. When these same plants with their containers are removed to the 

 rooms where man works and dwells, experience indicates that the plant will 

 lose its luxuriance and may even die. Among the excuses for failure to grow 

 house plants may be mentioned the dryness of the air, the presence of coal 

 gas, and a natural lack of sympathetic understanding with the plants. The 

 paramount picture of household plants is the uncanny success of the poor 

 people with their tin-can containers. To all appearances, these people have 

 disobeyed all the rules of culture in that the non-porous containers with in- 

 adequate drainage are in kitchens with a great range of temperature, where 

 coal gas is frequently present, and where the sunligiit is frequently of short 

 duration. 



The Porous Clay Flower Pot 



Many examinations of house plants that are gradually dying have shown 

 a general absence of insect pests and freedom from disease. However, when 

 the plant is removed from its jiot, it is usually quite noticeable that the po- 

 rous pot itself is dry, that the upper third of the soil is wet and the lower 

 half of the soil is powder dry. In this dry soil the roots are dead. The diag- 

 nosis from the conditions thus found is gradual death of tlie plant caused by 

 a lack of moisture in the area normally occupied by the feeding roots. 



An investigation of a broad nature has brought out some generalities 

 that explain a great many failures in growing house plants. A knowledge of 

 these factors leads to recommendations which may insure the successful home 

 culture of plants with a minimum amount of care. 



It is well known that warm air will hold more moisture than cool air. 

 AVhen the cool air of winter is introduced into our rooms and its temperature 

 raised by any heating apparatus, the little moisture that it originally con- 

 tained when cool is very small conqjared with the amount of moisture the 



1 The writer is indel)t<'d to Professor A. Vincent Osniun, Head of the Department 

 of Botany, for his keen interest in aiding in the solution of the many problems en- 

 countered in this investigation, and for his suggestions in making the results of 

 greater service to the public. 



