The effect of the substitute media on the development of the potted New Guinea Impatiens (Impatiens hawkeri)

Some kinds of agricultural castoffs such as sawdust (SD) and the powder of coconut coir (PCC) were used as growing media to substitute peat moss for the New Guinea Impatiens. It showed that all the substitute media should fit for the growth of the root system without disturbing the spatial development of the root. The growths of the plants in substitute media are all exceeded that in PM or only below the contrast indistinctly. The comprehensive indexes of plants in PCC and SD are 0.76 and 0.98, and the comprehensive indexes of plants in PSS and PPH are all higher than that in PM. It means that those four kinds of substitutes can be used to take the place of the peat moss totally as soilless growing media. In the period of 50–100 s, the differences of the Ultra-Weak Photon Intensity of the leaves among all the treatments are different significantly, and the trend is similar to that of the root. The photosynthesis of the New Guinea Impatiens is very different to the data of morphology evaluation indexes. There is no noticeable effect of the growing medium itself on the elements contents of the plant. The determinant may be the nutrients solution. There is no significant difference of the contents of chlorophyll in the plant that was planted in the substitute media between the PM. Under almost the same growth conditions, the Hoagland nutrients solution can make a steady and balanced supply of nutrients for the plant which cannot be evidently disturbed by the type of media. The substitute media have lower performance of preserving moisture and fertility, under normal cultivating conditions, the plants developed well, but in order to keep the plant in good condition, the substitute media depends more on extraneous nutrients from nutrients solution than PM.