It is important that the nutrients are available to the rose. This issue is highly determined by soil acidity.
The pH value of the soil is measured on a logarithmic scale running from 0 to 14. A pH of 0 is very acidic, and a pH of 14 is very alkaline. The pH level 7.0 is considered neutral. The ideal level for roses is 6.0-6.8, with 6.5 being the optimal level.
The soil may have sufficient amounts of nutrients, but if the pH level is far off one way or the other, the nutrients will not be available to the rose. The nutrients will be, what we call “locked up” and the rose will not be able to benefit from them. Adjusting the soil pH is necessary to have healthy plants.
Soils that are high in organic matter are less effected by a low pH. Organic matter holds onto nutrients. Soils low in organic matter and with an incorrect pH level will almost always yield a rose that exhibits nutrient deficiency problems. It may be necessary to have the soil tested, if roses are struggling, or before planting new roses.
Soil test samples can be sent to Utah State University Extension Services, for a nominal fee. The report of your soil test will reveal the content of current nutrients, which nutrients are lacking and recommendations to improve your soil.
Our next Blog Post will explain how to do this.