Stocks Seeds

Stock (Matthiola incana) is a treasured cool-season ornamental from the Mediterranean basin, prized for its powerful, clove-sweet fragrance that perfumes a whole bed. Its upright spikes carry densely packed blooms in soft pastels and rich jewel tones, making it a classic for borders, containers, and especially the vase, where stems are valued for their scent and long display.

Planting

Sow shallow, about 0.6 cm deep, and cover only thinly since this seed needs light to germinate well; sieved compost or vermiculite that lets light through works best. Keep the medium evenly moist at 18–24°C and seedlings emerge in 7–14 days. Start plugs indoors roughly 5–10 weeks before transplanting, pricking them into pots once two true leaves appear. Space plants 10–15 cm apart for cut flowers, or thin to about 25 cm in borders. Grow in full sun with 6+ hours of direct light.

Fertilizing

Test the soil before amending and avoid excess nitrogen, which produces weak, floppy stems. Watch for potassium deficiency, seen as brown leaf tips and margins at flowering, and supply adequate potassium through the growing and flowering phase. Stock prefers neutral-to-alkaline soil around pH 6.0–8.0 and struggles in acidic ground.

Care

Keep soil consistently moist but well-drained, watering at the base rather than the foliage to limit disease. Pinch out the growing tip of branching types for bushier plants with more spikes. Maintain good spacing and airflow to deter powdery and downy mildew, and watch for aphids, thrips, and flea beetles, worst at transplant. Harvest cut stems when one-third to one-half of the florets are open.