Black Currants Gone Wrong: Soil Acidity Unleashed Ruined HarvestsSeptember is a critical period for currant bushes. Photo: Pravda.ru by Maria Kruglova, https://creativecommons.org/public-domain/pdm/ Black currantsCorrecting Soil Acidity for CurrantsBlack currants are highly sensitive to pH levels, with an optimal range between 5.3 and 6.3. To resolve this, gardeners can apply slaked lime (known as "pushonka"). Applying Slaked Lime A procedure to neutralize soil acidity and improve nutrient uptake. For rapid correction in September, slaked lime is more effective because it takes effect before stable frosts arrive.