Various plant extracts have the potential to enhance growth and reproduction in vegetable crops but their nutritional composition may differ. The current study was aimed at analyzing the nutritional composition of leaf extracts for Moringa oleifera (moringa), Chlorophyta (algae), Symphytum officinale (Comfrey), Bidens pilosa (black jack) to prospectively increase their use as biostimulants in horticulture. Fresh plant leaves were collected at vegetative stage prior to flowering and processed for specific laboratory analytic techniques of major and trace nutrient elements. Analysis of variance results revealed that algae had significantly higher nitrogen and calcium levels of 8.13 and 18.69% respectively close to the levels of some commercially available fertilizers. Comfrey and blackjack had appreciably levels of potash of 4.39 and 3.78% respectively. Magnesium levels were very high in blackjack (60.54%) ahead of all the assessed plant extracts. All the tested plant materials had generally low levels of phosphorus. The leaf extracts of the four assessed plants are variable in their composition of major and trace elements but are in the range of nutritional requirements of most vegetable crops. Algae has the potential to be exploited as a biostimulant due to its observed high levels of nitrogen, calcium and trace elements close to the levels of some commercially available inorganic fertilizers.
Chlorophyta, blackjack, leaf extracts, Symphytum officinale, trace elements