Centaurea, Cornflower, Blue Boy ~ 100 seeds

Sun Preference
Full-Sun
Bloom or Harvest Time
Spring, Summer
  $2.99

Description

Centaurea cyanus
Hardy Annual
Spring/summer bloom
Can handle light frost

A butterfly, bee, & hummingbird favorite!

These classic flowers enjoy a very special place in the hearts of all cottage garden lovers. Their 1½-inch thistle-shaped blossoms are a brilliant electric-blue color that rivets the eye. Colorful and showy in the spring garden, Blue Boy makes a stunning landscape display and equally arresting bouquets to enjoy indoors. These are beautiful old-fashioned flowers to enjoy on their own or to interplant lavishly with other spring flowers.

Seed Starting Successfully

Start your garden from scratch with Gertens' wide variety of seed packets! Whether you're a seasoned gardener or just starting out, we have seeds for every skill level and garden size. From colorful flowers to delicious vegetables, our seeds are carefully selected for their quality and performance.

Seed Starting Successfully

Grow Your Best

When to Grow Veggies & Fruits

From Our Experts

Details

Cold Winters: March - May 
Mild Winters: October - April 
Sun/Shade: Full sun 
Sow Seeds: 1 - 2 inches apart, 1/2 inch deep 
Days to Germinate: 7 - 10 days 
Mature Height: 3 - 3½ feet 

TO START OUTDOORS 
Sow seeds in a finely textured garden bed in full sun as soon as soil can be worked. In mild winter areas, where the ground doesn’t freeze, plant in fall for next spring’s bloom. Space seeds 1 to 2 inches apart and cover 1/2 inch deep. Keep seed bed moist until seedlings emerge in 7 to 10 days. Weed and water carefully. Thin seedlings to 6 to 8 inches apart.

TO START EARLY INDOORS 
Sow seeds 1 to 2 inches apart in a container of seed starting mix, 2 or 3 weeks before last expected frost. Cover 1/2 inch deep, keep moist and provide a good light source until seedlings are transplanted outside. Plant 6 to 8 inches apart into fertile garden soil in full sun when plants are 3 to 4 inches tall. Seedlings grow quickly; plant out before the roots get crowded.

GROWING NOTES 
In mild winter areas the best cornflowers (aka Bachelor Buttons) result from seeds sown in fall to bloom the next spring. In cold winter areas where ground freezes, plant in early spring to get sturdy plants that will flower for many weeks if faded blossoms are removed.

More Information

Mature Height (Range) 37" - 48"
Spacing in Row 1-2", thin/transplant 6-8"
Days to Germination 7-10 days
Planting Depth 1/2"
Seed Packet Type Flowers
Plant Life Cycle Hardy Annual
Bloom or Harvest Time Spring, Summer
Sun Preference Full-Sun
Common Family Name Bachelor Button
Brand Renee's Garden

Product Questions (12)

Starting times will vary depending on the vegetable you are growing. Each seed packet will have specific sowing instructions for that type of vegetable. Some plants, such as tomatoes and peppers, should be started indoors, 6-8 weeks before the last frost...
The process of bringing seeds outside is called hardening off. Hardening off is generally done sometime after the seedling has two full sets of normal leaves. In Minnesota, you want to begin hardening off seedlings in late April/early May.  To ...
If you have a southern facing window with all day sun, you may grow seedlings in a windowsill. Be sure to rotate the seedlings frequently to ensure the plants do not lean heavily towards the sun. For more even results, use a grow light, positioned roughly...
We recommend using either high intensity T5 fluorescent bulbs, or LED grow lights. Both setups will produce excellent results. T5s are the typical grow light, are economical and come in frequencies that are helpful for plant development. LED technology...
Grow lights should be kept roughly 4-5” above the top of seedling leaves. If you are using very powerful LEDs, you could even keep them 8-10” away.
Grow lights should be used to mimic a natural sunlight cycle for plants. We recommend using them 12 hours a day, from roughly 7am to 7pm.  
A variety of seedling trays exist for seed starting. If you are starting smaller seeds, a simple peat cell tray works great. However, the larger the seed, the larger the initial pot should be. If you are starting larger seeds indoors such as: sunflowers...
Do not start any type of fertilizer regime for young seedlings until they have at least two full sets of regular leaves. Start with a root stimulator, then after a month you may move on to a gentle, weak (half strength) water-based fertilizer. Remember...
Let the roots tell you when to transplant. When you begin to see the seedling’s root growing out of the bottom of their current pot, it is time to transplant up to something larger. We recommend using a 4” nursery pot to transplant most seedlings. In...
Gertens carries a wide variety of both spring and autumn planted bulbs. Spring planted bulbs, such as gladioli and dahlias, are best started indoors in early April, and planted outside once the soil temperatures are above 55 F. Autumn planted bulbs, ...
The big three tips are: 1) Staking and training 2) Feeding and watering and 3) Harvesting and enjoying. 1) Keeping plants trained and staked allows air circulation around crops and provides much-needed support for produce as it grows...
Gertens does carry an assortment of both perennials, as well as annual and perennial wildflower mixes. It is important to remember when growing perennials, that you will not get any flowers the first year of growth. It often takes a perennial 2-3 years...
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