Growth and biomass yield response of Cleome gynandra L. to different levels of giant kelp extracts supplemented with kraal manure

• Spider plant has been hindered by problems, including low investment in research. • Giant kelp extracts (GKE) and kraal manure are used to improve crop productivity. • In this study, GKE and KM significantly affected growth and yield of spider plant. • Applying GKE at 1 mL/L GKE produced the highest plant height and stem diameter. • Generally, different GKE and KM levels influenced the productivity of spider plant. Cleome gynandra (hereafter, spider plant) is an annual leafy vegetable considered drought-tolerant due to its ability to withstand high temperatures. However, this plant is low-yielding, which limits its use as a future crop. Therefore, the current study investigated the effect of giant kelp extract (GKE) supplemented with kraal manure (KM) on spider plant growth, yield, and biomass. It is hypothesised that different levels of supplements will result in different levels of productivity. Two field experiments (season 1 and season 2) were conducted in a research field at the University of Fort Hare. The field trials were laid out in a split-plot design: the main plot consisted of KM at three levels (0, 30, and 60 kg/345 m 2 ), and the subplots were assigned to five GKE (0, 1, 2, 3, and 4 mL/L), which were replicated three times. The results indicated a consistent increase in control (0 kg/345 m 2 ) in both seasons. However, the growth parameters of spider plants remained unaffected by increasing KM application rates (60 kg/345 m 2 ). Spider plant treated with 1 mL/L GKE increased plant growth parameters in both seasons. Administering 3 mL/L GKE + 60 kg/345 m 2 KM resulted in the highest leaf yield in season 1. The increase in plant growth parameters when administering GKE suggests that its application in small quantities improves plant productivity. Thus, this study confirms that the sole or combination application of KM and GKE plays a significant role in increasing plant growth, yield, and biomass.