8 THE CULTURE OF POT-PLANTS 



The three principal ingredients in plant food are nitrate, 

 phosphate, and potash. The two last remain in the soil 

 until they are used by the plants, but the former quickly drains 

 away. If, therefore, there is a deficiency, it is most likely to 

 be in nitrate. Good potting soil, such as a mixture of three 

 parts of turfy loam, two parts of leaf-mould or decomposed 

 manure, and one part of sharp sand, contains all the food 

 that is necessary. There is no need to add anything else for 

 a time. There is much nutriment in old turf, which also 





Fig. 4. — Potting Bench. 



gives firmness to the whole, and much more in leaf-mould or 

 decomposed manure. The sand has no food value, its only 

 object being to keep the soil porous — that is, to provide 

 spaces between the particles which air and water can penetrate, 

 and through which surplus water can escape. When plants 

 have been freshly potted in this mixture, they have all the 

 food they can use ; it is not until their roots have grown 

 through it, and become matted at the side, that there can be 

 any scarcity. The plants can then be transferred to larger 

 pots, or else the food required can be supplied in the form of 

 a fertiliser. 



Thethree principal ingredients already mentioned — nitrate. 



