Also included are instructions on how to test your soil, and how to correct your pH if necessary. The Kelway professional direct pH soil tester is used by thousands of nurseries across the world. It operates on the principle of electrical potential between two dissimilar metal plates. No batteries required. When inserted into moist soil, the HB-2 registers degree of acidity on the upper scale.
Litmus paper is difficult to use and interpret.
The Kelway Professional pH tester is portable, rugged, convenient, operates without a power source and is not overly sensitive to temperature variances. Great for individual pots or for entire beds. The Kelway Soil pHD can more than pay for itself the first time it is used. The instructions include guidance on how to adjust soil pH. To test soil acidity the tester is inserted 2 inches into moist soil, and in minutes - the pH is displayed on the meter. The Soil pHD creates its own power by a tiny current between the tester's two different metal rings.