From our perspective as Cornflowers (Centaurea cyanus), we are not overly demanding plants. We originate from European grain fields, which means we are accustomed to open, sunny spaces with well-draining soil. For your balcony or patio, this translates to a few key needs. Most importantly, we require a location that receives at least six to eight hours of direct sunlight daily. We stretch our stems and open our vivid blue petals wide to bask in the sun's energy. While we can tolerate some light shade, insufficient light will cause us to become leggy as we strain for the sun, and our flowering will be sparse. We also need protection from strong, damaging winds, so a slightly sheltered corner of the balcony is ideal.
The choice of container is critical for our root system. We do not like to have our feet constantly wet, so excellent drainage is non-negotiable. Please select a pot that is at least 12 inches deep and wide, with several drainage holes at the bottom. A fabric grow bag or a terracotta pot is excellent as they allow the soil to breathe. Do not use a saucer underneath, or if you must, empty it after watering to prevent us from sitting in water. For soil, we prefer a light and airy potting mix. Avoid heavy, clay-based garden soil, which will compact in containers and suffocate our roots. A standard, well-draining potting mix is perfect; we are not fussy about high fertility.
We are best started from seed directly in the pot where we will grow. We do not appreciate our roots being disturbed by transplanting. The best time to sow us is in the cool days of early spring or early autumn. Simply scatter our seeds evenly over the surface of the moistened potting mix and gently press them in, covering them with a very thin layer (about 1/4 inch) of soil. We need darkness to germinate. Keep the soil consistently moist but not waterlogged. With temperatures around 60-70°F (15-21°C), you should see us sprout through the soil in 7 to 14 days.
Once we seedlings are a few inches tall, we need space to grow. If we are too crowded, we will compete for light and nutrients, resulting in weak plants. Thin us out by snipping the weakest seedlings at the soil line, leaving the strongest ones spaced about 6-8 inches apart. When it comes to water, we are quite drought-tolerant once established. Water us deeply when the top inch of soil feels dry to the touch, allowing the water to flow freely from the drainage holes. Then, let the soil dry out somewhat before watering again. Overwatering is a sure way to make us unhappy. A light feeding with a balanced, liquid fertilizer every four weeks during the growing season is plenty to support our flowering.
Our main goal is to produce seeds to ensure the next generation. To encourage us to keep producing our iconic blooms for you throughout the season, you can practice "deadheading." This simply means snipping off the flower heads as soon as they begin to fade and wilt. By removing the spent blooms, you prevent us from putting energy into seed production and instead, we will redirect that energy into creating new flowers. This will keep us looking tidy and promote a long, vibrant display of colour on your balcony from late spring until the first frosts.
