Garden Scheme
Ocimum basilicum var. thyrsiflora
Thai basil is a compact annual herb that reaches about 18 inches tall and wide, bringing purple stems and an anise-licorice character to the edible garden. Ocimum basilicum var. thyrsiflora earns a spot close to the kitchen, where frequent cutting is easy. Its upright, branching habit makes it useful as a small repeated accent among lower vegetable and herb plantings.
Space Thai Basil 12 inches apart, measured center to center (30 cm).
The mature spread is about 18 inches (45 cm), so plants set at that distance grow together into a closed canopy over the bed.
Treat 12 inches as a planning baseline — cultivar and local growing conditions shift the final footprint.
Set Thai basil in the sunny front or middle of a vegetable bed, rather than behind taller crops that will shade it later in summer. Place it beside a path, bed edge, or container rim where stems can be pinched and harvested without stepping into the planting.
Space plants 12 inches apart, center to center, for a close, orderly planting. Each plant can fill roughly an 18-inch-wide space, so allow its foliage to mingle lightly without burying it beneath neighboring crops. In a narrow bed, use a single row along the accessible side and reserve enough open edge to reach every plant for regular harvest and pinching.
Give Thai basil full sun and regular water throughout its growing season. A position with open exposure works best for keeping the planting easy to manage, especially where nearby vegetables become dense. Use a bed or container arrangement that lets water reach the root area without making the foliage crowded or difficult to inspect.
Expect harvests from early summer into early fall, with plants reaching maturity in about 70 days. Mid-summer to early-fall bloom can extend the plant’s presence after the main harvest period, and the flower spikes support pollinator activity. Pinch growing tips and emerging flower buds when leaf production is the priority, then leave selected plants to bloom if that suits the bed’s late-season role.[1][2]
Do not pack Thai basil tightly into a humid, enclosed corner of the garden. Leave a clear gap from neighboring foliage and avoid a layout that forces overhead watering onto the leaves; airflow and quicker drying reduce the conditions that favor basil downy mildew. Make room to remove an affected plant promptly if foliage develops yellowing with gray growth beneath the leaves.[3]