A note on the employment of a mixture of sand and calcium bentonite as the growth medium in pot culture and the establishment therein of a sward of perennial rye grass

Summary and conclusions

1. A mixture of sand and bentonite (after converting it to the calcium clay), containing 6 per cent, by weight of the latter, was found to be a suitable medium in pot cultures for the growth of grass. A good sward of perennial rye grass was established in the medium by suitable watering, manuring and cutting of the grass, within 11 weeks of sowing.

2. The mixture allowed of easy control of the moisture content, and appeared to possess a moisture-retaining capacity comparable with that of a natural soil.

3. The mixture is almost totally deficient in both nitrogen and phosphoric acid, and markedly deficient in potash and in some of the less common elements necessary for plant growth.

4. In view of the above properties and of the buffering action due to the presence of the bentonite, the mixture would appear to be suited to the more general study in pot culture of plant nutrition problems, and to offer several important advantages over either sand alone or natural soil for this purpose.