This last consideration was one of major importance, and to meet all 
these requirements, it was decided to use the following basic physical in- 
gredients: 
¥s peat moss—for retention of moisture. 
Ys shavings—to provide aeration and to take the place of the peat 
as the peat decomposes. 
¥; fine sand—to insure good drainage and aeration and to furnish 
physical support. 
This mixture should be fumigated before use to eliminate weeds, worms, 
snails, slugs, bacteria and fungi. 
These basic ingredients were purposely selected to supply little or no 
nutrient. The nutrient requirements could be met by adding certain fer- 
tilizers to supply nutrients in proper proportion to provide a fertile non- 
saline growing mix. 
The fertilizers that were added are: 
1. Potassium Nitrate: Both potassium and nitrogen are essential nu- 
trients for plant growth. This material provides a maximum of both 
in a minimum of bulk. The nitrogen here is immediately available 
(about 14% N, 46% K,0O). 
2. Treble Superphosphate: This material is actually mono-calcium 
phosphate made by treating phosphate rock to make the phosphorus 
more available to plant growth. It is only sparingly soluble and 
therefore long lasting. 
3. Dolomite Lime: This material supplies both calcium and magne- 
sium, and in addition it counteracts the acidity of the physical in- 
gredients which are too acid for optimum growth. 
Since there is not an unlimited reservoir of nutrients in the mix, it is 
necessary to provide the required elements from time to time as the plants 
are growing. The initial concentrations are optimum but nitrogen will be 
of primary concern because it is most readily leached and is used in two 
ways in the mix: 
1. Plant uptake. 
2. Microorganism uptake as they slowly decompose the organic 
materials in the mix. 
Liquid feeding is perhaps the safest and most accurate method of fertil- 
izing. Nitrogen can be supplied as urea (46%N), phosphate as mono-am- 
monium phosphate (12% N, 61% P2O;), and potassium nitrate (14% N, 
46% K20). These materials can all be mixed with one another in solution. 
They provide a maximum of nutrient with a minimum of salinity. 
There are several fertilizers on the market today that answer these re- 
quirements, Instant Vigoro, RX-15, and Folium to name a few. We use and 
recommend a formula recommended by Mr. Matkin as being best for our 
potting mixture — a product known as Formula 312. In areas where water 
contains an excessive amount of sodium salts, the use of agricultural gypsum 
is suggested (usually one tablespoon to a six inch pot every three months is 
sufhcient). Another corrective procedure is to irrigate with lime sulfur 
solution (diluted 1:200) every three months. 
anh Oe 
