Ronald L. Shumack

Lime requirements of Boston ferns: II. Foliar and medium analysis

Abstract Growth response and nutrient levels in the foliage and growth medium were compared using Nephrolepsis exaltata (L.) Schott ‘Com‐pacta’ ferns grown in a peat‐perlite medium with 4 rates of dolo‐mitic limestone (0.0, 1.2, 2.4, and 6.0 kg/m3) and 2 rates of gypsum (0.0 and 1.2 kg/m3). Incorporation of dolomitic limestone and gypsum resulted in greater growth compared to treatments without dolomitic limestone and gypsum, but dolomitic limestone rates of 1.2, 2.4, or 6.0 kg/m3 resulted in no difference in fern dry weight. Addition of gypsum resulted in higher foliar S levels. Suppressed fern growth was associated with lower foliar Ca and S levels. When 6.0 kg/m3 of dolomitic limestone was added to the medium, foliar N was lower and nitrates in the medium were higher compared to ferns grown with no dolomitic limestone. Addition of gypsum and dolomitic limestone to the medium increased soluble salt levels.

Liming materials and rates for Boston ferns in a soilless medium: I. Effect of pH

Abstract The growth of Nephrolepis exaltata (L.) Schott ‘Compacta’ was compared for plants growing in a peat‐perlite medium limed at three rates using two liming materials, dolomitic limestone and hydrated lime. Greatest fern growth occurred with no lime or low lime treatments. Both liming materials produced rapid changes in pH, which remained relatively consistent for 16 weeks. Two procedures were used to monitor pH; a standard soil testing procedure and effluent analysis. The pH ranges resulting in the greatest growth were 3.8–5.1 for media pH values and 3.6–5.5 for effluent pH values.