Thai Magic

Basil (Ocimum basilicum) is commonly hit by downy mildew, which shows up as yellow patches on leaves with gray-purple growth on the underside, especially in cool, humid weather. Remove and discard affected leaves immediately, water at the soil line (not overhead), and space plants for airflow; if it keeps spreading, use a labeled copper or potassium bicarbonate product according to the label. Keep plants in full sun to dry foliage faster after morning dew.

Start light harvesting once plants are ~6–8 weeks old or when they have multiple sets of true leaves (and consistently after the plants are established). For a full harvest, cut when plants are around 60 days from sowing: look for dense, healthy leaf growth with flavorful leaf blades across the stems, not sparse growth at the top. Harvest by pinching/cutting just above a pair of leaves to encourage branching; if the plant begins setting flower spikes, flavor can turn sharper and you should harvest more frequently.