Some ingredients might be difficult to find: I had to buy chalk at drugstore prices to run tests on these composts. And most gardeners would find hoof and horn meal hard to obtain. Also, original John Innes formulae call for steaming the first part of each mixture before adding other ingredients, a difficult operation for home gardeners.
Another standardized growing medium on sale in England is made up of two parts (by volume) of peat, two parts fine vermiculite (equivalent to the size used as a plaster aggregate in this country) and two parts kaolin clay. To a bushel of this mixture a fertilizer is added (8 oz. in all) made up of two parts magnesium sulfate, two
parts potassium nitrate, three parts ammonium sulfate and four parts superphosphate (all fertilizer ingredients are by weight).
IN SAND AND PEAT
A method of growing all kinds of plants in sand and peat was developed in the greenhouses of Vaughan's Seed Company, Western Springs, Illinois, and has been continued by Frank McFarland at Half Day, Illinois, following the razing of the Vaughan range several years ago. In this system, the greenhouse benches are packed with a mixture of sand and peat which serves largely as support for the plants; nutrient elements are provided by flooding the benches with fertilizer solutions. Frank McFarland uses nothing else to grow his superb greenhouse chrysanthemums. (He cuts a crop of blooms every day in the year on an exact schedule, and they command premium prices on the cut flower market.) This method of growing plants to maturity would be difficult for the amateur greenhouse owner, but is ideal for starting and temporarily growing seedlings, either in the house in a sunny window or in coldframes, hotbeds and home greenhouses. The following modifications have been worked out for amateur use:
||50 per cent Swedish, German or Canadian peat, plus SO per
cent sharp sand
||50 per cent Swedish, German or Canadian peat, plus 50 per
cent horticultural-grade vermiculite (Terralite)
|| 50 per cent Swedish, German or Canadian peat, plus 50 per
Use clean (new or sterilized) flats, pots or greenhouse benches. The new "root-through" peat-and-fiber composition pots can be used without sterilization. Fill whatever containers you use with one of the following "soil" or growing mixtures:
After filling the container with growing medium, soak with plain water; allow the soil mixture to settle before sowing seeds. After sowing, cover growing unit with one of the plastic bags used to cover freshly-pressed clothes or with other thin plastic film. Often, the container will not have to be watered again until seeds germinate. After germination, water once with a soluble complete fertilizer such
as the following trade-name products: Rapid-Gro, Plant Marvel. Use one level teaspoonful to one quart of water.