10 Cardinal Basil Seeds

Cardinal Basil stands out from ordinary sweet basil for one striking reason: instead of plain spikes, it crowns itself with thick, showy flower heads in a deep wine-red to burgundy colour that rise well above its broad, glossy green leaves. That bold contrast makes it as much an ornamental plant for borders, pots and cut arrangements as a kitchen herb. The leaves carry the classic warm, sweet basil aroma with a clove-like, slightly spicy edge, so they still earn a place in fresh salads, sauces and garnishes while the burgundy blooms add colour to the plate and the garden alike.

Planting

Cardinal Basil is a warm-season annual and is sensitive to frost, so timing matters. You can start seed indoors about 6 to 8 weeks before the last spring frost, or sow and transplant outdoors only once all danger of frost has passed and the soil has warmed; wait until nighttime temperatures stay reliably above 10 C before moving plants out. Cover the seed lightly, to a depth of roughly 0.6 cm. Germination usually takes around 5 to 10 days, and is best when the soil or seed-starting mix sits at about 18 to 21 C, with seedlings often emerging within 5 to 7 days. Give the plants a full-sun position with at least 6 to 8 hours of bright light a day; they will tolerate part sun but always prefer a warm, sheltered, sunny spot. Thin or space plants to about 15 to 30 cm apart for full-size growth, or closer at roughly 10 to 20 cm if you are growing for cut leaves, with direct-sown rows about 45 cm apart. In Egypt the main constraint is cold nights rather than summer heat: in the Nile Delta and Lower Egypt, start seed under protection or in a seedbed in late January to February and transplant out in March to April once nights are reliably above 10 C, for a long cutting season from June through October. In the warmer winters of Upper Egypt the frost-free window is wider, so transplanting can begin a few weeks earlier, from late February into March, and a second autumn crop is possible. Avoid sowing into the cold of mid-winter (December to January) in either region.

Fertilizing

Keep feeding gentle and low in nitrogen. Work a low-nitrogen starter fertilizer into the bed before planting. If growth slows about two months after planting, give the plants a nitrogen boost by side-dressing with roughly 0.1 to 0.2 kg of calcium nitrate per section of row. Basil grown in the ground in good soil often needs no extra fertilizer at all. For plants in containers, feed with a diluted balanced liquid fertilizer every 3 to 6 weeks, ideally an organic-based balanced feed, and steer clear of high-potassium feeds.

Care

Cardinal Basil is not drought tolerant and needs a fairly constant supply of soil moisture, so keep the soil evenly moist and never let it dry out completely. Water deeply about every 7 to 10 days, and more often for plants in containers. Water at the base of the plant in the morning and avoid wetting the foliage, which helps reduce disease. Move or thin seedlings to their final spacing once they have formed 2 to 3 pairs of true leaves, and transplant indoor-started seedlings out about 6 weeks after sowing, once frost has passed. Pinch out the growing tips regularly, at least once a week, to keep the plant bushy and full. For the best leaf flavour, harvest in the cool of the early morning and pick just before flowering, pinching out flower buds as they appear; left to bloom, plants turn woody and the leaves become more bitter, though with Cardinal Basil many growers let some of the burgundy flower heads develop for their ornamental colour. For a full cut, take the whole plant back to about 10 to 15 cm above the ground to encourage fresh regrowth. Watch for common pests such as aphids, slugs and snails, spider mites, whiteflies, Japanese beetles and leafhoppers, and for diseases including basil downy mildew, Fusarium wilt, grey mould, bacterial leaf spot and damping-off; watering at the base rather than over the leaves helps limit downy mildew.