The invention provides seeds and plants of spinach hybrid SVVB0421. The invention thus relates to the plants, seeds, plant parts, and tissue cultures of spinach hybrid SVVB0421 and to methods for producing a spinach plant produced by crossing such plants with themselves or with another plant, such as a spinach plant of another genotype. The invention further relates to seeds and plants produced by such crossing. The invention further relates to plants, seeds, plant parts, and tissue cultures of spinach hybrid SVVB0421 comprising introduced beneficial or desirable traits.
