RESUMEN
The dragon fruit (Hylocereus costaricencis) is a new emerging fruit crop, there is very less information available on the spacing and fertilizer dose requirements of this crop so the present study was carried out to find the effect of fertilizer doses, spacings, and interaction effect of both on plant growth of dragon fruit (Hylocereus costaricencis) at the Orchard, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore. during the year 2022. The design of the experiment was a split plot with four main plots viz. M1 = 3.5 x 2.0 m2, M2 = 3.0 x 3.0 m2, M3 = 3.0 x 2.5 m2, M4 = 2.5 x 2.5 m2 and six sub plots viz. S1 = N540 P420 K360, S2 = N495 P385 K330, S3 = N450 P350 K300, S4 = N340 P260 K225, S5 = N225 P175 K150, S6 = N0 P0 K0 g per pillar was applied and replicate four times. A significant difference was observed in terms of vine length (m), cladode girth (cm), cladode length (cm), and cladode number when different doses of fertilizers were applied. The highest vine length (2.96), cladode girth (24.52), cladode length (67.21), and number of cladodes (67.48) were observed in S3 (N450 P350 K300). Similarly, the highest vine length (2.503) and cladode girth (19.78) were observed in M4 (2.5 x 2.5 m2). The highest cladode length (67.47) was observed in treatment combination M2S3. Hence, the application of fertilizer dose S3 (N450 P350 K300) and adoption of spacing M4 (2.5 x 2.5 m2) is good to enhance the vegetative growth characters of dragon fruit under Tamil Nadu conditions.