158 MASS. KXPERTMEXT STATION BULLETIN 277 



sufficient soil so tliat very little volume is left above the surface of the soil 

 that can be filled with ^vater. In glass containers, soils that are wet to the 

 touch need no ^^ater; if they are barely nu)ist, water may be added. Though 

 a drainage hole is not necessary, it may be helpful in case free water gathers 

 in the soil. In a period of three months in a greenhouse, plants in glass con- 

 tainers required less than half as nuich water as those in clay j^ots. With 

 house plants, the diflference would be wider. 



In Figures 1 and 3 are shown experiments with various types of pots; 

 including glass. The glass containers in these photographs did not have drain- 

 age holes, yet glass produced ])lants as good as tho-^e grown in other con- 

 tainers, or better. 



In order to demonstrate that glass containers were productive beyond the 

 vegetative phase of the ])lant, an experiment was prolonged through the 

 blossoming stage with calendulas. The plants Mere in 4-inch clay pots, 4-inch 

 Bakelite-varnished paper pots, and pint glass fruit jars (holding the same 

 volume of soil as a 4-inch pot). The plants in the fruit jars produced more 

 flowers than those in any other type of container, as is shown in Table 5. 



There are many forms of glassware that may be adapted to the growing 

 of plants. Cheap glass tumblers and jelly glasses may he used for small 

 plants. The ornate jardiniere may be better used as a plant container than 

 as a means to hide a clay j^ot. 



Rubber Flower Pots 



In the course of the investigation, tests were conducted with a new type 

 of flower pot made of rubber.^ The saucer is attached, and a drainage hole 

 enters the saucer from the side of the pot at the base. Careful tests indicated 

 that the pots contained no substance harmful to the plants. 



Some of the pots were coated with a Bakelite varnish; some with as- 

 ])halt. The remaining pots w^ere not coated, thus allowing the roots of the 

 plant to come in direct contact with the rubber. All produced ])lants that 

 compared favorably with plants in glass and clay pot containers. 



Figure 4 illustrates the results in the rubber pots as compared with clay 

 pots. Maidenhair fern was used as an indicator plant. The jilants were grown 

 in an office window and were practically equal when potted, 50 days before 

 the ])h()tograph was made. At the time of ])liotographing, the larger mimbe" 

 of old and new fronds in the rubber pots indicated that the plants in these 

 pots Mere the more thrifty. In Table 6 is given the count of old, new, and 

 total fronds of each pot. The rubber pots are slightly flexible and the two 

 in the photograph have been in use for over a year Mithout any sign of 

 deterioration. 



^ ^^anufacture(l by the Fisk Rubber Company, C'hicopeo Falls, Massachusett.s. 



