Growing Cornflowers In Containers – A Full Guide

Introduction to Growing Cornflowers in Containers and Pots

The Cornflower plant is an herbaceous annual plant that belongs to the Asteraceae family and it is also called a Bachelor’s Button. Cornflower plants are about 30–90 cm tall with also narrow gray-green color leaves; they produce papery flower heads surrounded by bracts. The plants make excellent cut flowers and attract bees and butterflies and other pollinating and beneficial insects. Although blue is the most common color; white, red, pink, and purple color varieties are also available. In this article we also discuss the below topics about growing Cornflowers;

  • How much time it takes to grow Cornflower
  • Cornflower growing tips
  • What is the best fertilizer for Cornflower
  • Growing Cornflowers indoors
  • What is the best soil for growing Cornflower
  • How do you know when Cornflowers are ready to harvest
  • Tips to grow and care for Cornflowers
  • Container Care for Cornflower
  • Growing Cornflowers in pots

A Step by Step Guide to Growing Cornflowers in Containers and Pots

Cornflower plants are easy to grow and flower best in sunny positions. Cornflower plants should self-seed in the fall, but collecting Cornflower seeds is extremely easy, and growing Cornflowers from seeds are a great way to spread them around your garden and with your neighbors.

Different Varieties of Cornflowers

The following are the different varieties of Cornflower.

  • Blue boy variety – The Blue boy Cornflower variety has a vivid periwinkle blue.
  • Tall double mixed colors Cornflower variety – This variety has a shade of white, pink, and blue.
  • Blackball Cornflower variety – This is a rare variety with deep crimson poms.
  • Dwarf blue midget variety – The Dwarf blue midget Cornflower variety blooms begin at 6 inches, and container-worthy plants max out at 12 inches.

Cornflower has been developed into several named cultivars that offer different colors besides the traditional blue form. Usually, mixing different colors in a single planting makes the colors more impactful.

  • ‘Burgundy Beauties’ has a mixture of deep purple color and whitish flowers on plants about three feet tall.
  • ‘Dwarf Blue Midget’ is a blue-flowered form that reaches about 12 inches tall.
  • ‘Florence Mix’ is also 12 inches tall and has a mix of white and pink blossoms.
  • ‘Almost Black’ has deep purple-burgundy blossom on plants to 3 feet tall.

Tips for Growing Cornflowers in Containers

Tips for Growing Cornflowers in Containers
Tips for Growing Cornflowers in Containers (Pic source: Pixabay)
  • Cornflowers are annuals and they should be planted during the cool season and will decline as the weather heats up. Plant Cornflowers in full sun to get the most blooms and sturdier stems. They can take a little shade, particularly in the afternoon, but will perform best in all-day sunshine.
  • Cornflowers are adaptable and will grow in the poorest of soils. Ideally, they prefer a neutral to slightly alkaline soil pH level. Established plants can tolerate dry soil, but regular water will keep the Cornflower plants healthier.
  • The Cornflower plants can become floppy and can be flattened by rain or wind.
  • Pick a sunny spot with well-drained soil for growing Cornflower. Make sure that the place you’ll be planting them in has soft soil and no weeds. As the seeds sprout, they’ll be a bit delicate, so give them the best start by helping their roots and stems spread out easily.
  • Water the soil before you plant if it’s dry and you want it to be moist, but not standing in water. Then, add the seeds to the soil. You will want to place the seeds about 0.5 inches or 12mm deep, and each row of seeds must be at least 12 inches or 30 cm apart. Cover the seeds with soil.
  • You might wish to label your Cornflowers with a plant tag, so you’ll know where they will be sprouting. You should start seeing sprouts in a week or two weeks.

Ideal Conditions for Growing Cornflowers in Containers

  • Cornflower plants can be grown almost anywhere and grows best in full sun.
  • For spring/summer growth, the seeds need 85 to 95 days to reach flowering maturity. They thrive in temperature levels ranging from 15 to 26°C with soil temperatures at least 12°C.
  • The Cornflower plant is drought tolerant, and it can even survive a light frost. Cornflower seeds also can be germinated indoors if heavy frost is on the horizon. The fall or winter growth period stretches from 200 to 260 days.
  • Allow the soil to dry out slightly between watering and do not allow the soil to become too dry, or the plants may flop over. However, the Cornflower plant is drought tolerant and will easily spring back from under-watering.
  • Feed Cornflower plants once per month during the spring and summer months using a balanced flower fertilizer. The Cornflower plant can be invasive if the soil is too fertile, so avoid over-fertilizing.

Soil Requirement for Growing Cornflowers in Containers

  • Cornflower plants grow well on pretty average soil without added fertilizer or compost. Try and provide an average well-drained garden soil.
  • Unlike most of these garden flowers, the Cornflower plant prefers soil on the alkaline side, with a pH level between 7.2-7.8. Although you can add crushed limestone to the garden beds if your soil is on the acidic side.
  • Use well-draining soil for growing Cornflower plants and the container must have several drainage holes. You may even use a soilless mix.
  • Cornflower plants prefer soil on the dry side, so the potting mix must be one that will not retain too much moisture.

Light and Temperature for Growing Cornflowers in Containers

When it comes to temperature, Cornflower plants are fairly agreeable, tolerating both light freezes as well as the hottest summer days. The plants will tolerate humidity, but keep a close eye on them, as it leaves them susceptible to fungal disease.

Cornflower plants prefer full sun but can tolerate partial shade. The plants need lots of light to produce their array of flowers. Temperature-wise, these plants are tough. Young seedlings can tolerate light freezes and often germinate in the late winter and early spring. Weaker plants will die back and hardier plants continue to survive and flourish. These plants tolerate heat, but in the most extreme heat conditions need extra attention to keep them healthy.

Best Way to Propagate Cornflower for Growing in Containers

  • The seed is the easiest method to propagate these plants and the way which most people choose. You can sow Cornflower seeds directly in the soil or start the seeds in containers.
  • Cornflower seeds will germinate in 7 to 14 days. Once germinated, you should thin them down to one plant each 8-12 inches.
  • Your plants will fill in space once they begin to push up plant leaves and stems, and in time they’ll flower.
  • To collect seeds from Cornflower, wait until the flowers have faded naturally on the plant and fully dried. Then, cut the flower off of its stalk, and break it up to reveal the seeds hiding within. The Cornflower seeds are oblong with a tuft of brownish hair at the end.
  • Allow your seeds to dry for 7 to 10 days in a cool, dry location and then store them until the next planting season.

Growing Cornflowers from Seeds in Containers

Cornflower seeds are very easy and inexpensive to grow in the home garden. These plants produce single or double flowers with fringed petals and gray-green color leaves. Dwarf plant varieties are suitable for edging and borders, while taller varieties are popular in cottage gardens. Though, since taller varieties may not be readily available at local nurseries, planting Cornflower seeds is the only way to get them in the garden. Usually, they are easy to grow both indoors and outdoors.

Seed Depth – Cornflower plant requires sunlight to germinate. Don’t cover them up with more than 1/16 inches of fine topsoil.

Seed Spacing – Plant or thin 6 to 12 inches apart.

Days to Germination – Usually, growing Cornflower from seed takes 7 to 21 days at 18°C to 23°C. Cornflower seeds germinate at the early end of the range.

If you do decide to start Cornflower seeds indoors, do so 6 to 8 weeks before you plan to set them out and grow them in a bright window or under fluorescent grow lights. Then, use deep peat pots to allow for low-shock transplanting, and don’t let them dry out.

Planting Cornflower Seeds Indoors – Cornflower seeds are very easy to sow indoors as well as outdoors. Watch the calendar and plant them accordingly, about 1 month before the last frost or about a month before you’re planning to set them outdoors.

Fill containers or peat pots with your choice of growing medium. Once the containers are filled, moisten the mixture and then allow it to drain. Then, sow 3 to 4 Cornflower seeds per pot and cover with another 1/2-inch of growing medium. Mist the top lightly with water, and then cover containers with plastic bags or sheeting. Place the containers in a warm location to allow seeds to germinate.

After seed germination, remove the plastic and then place the containers under grow lights or in a sunny location. Once seedlings reach 2 inches tall and have one pair of true leaves choose the strongest seedling to keep and then pinch off the others at soil level. Use a water-soluble fertilizer once on all the containers, and then transplant seedlings outdoors when they are 4 inches tall (or less).

Water and Fertilizer Requirement for Growing Cornflowers in Containers

Water your Cornflower plants once per week only on weeks that do not receive rainfall. Allow the soil to dry out between watering. Do not allow the soil to become too dry, or the Cornflower plants may flop over. However, the Cornflower plant is drought tolerant and will easily spring back from under-watering.

If your soil is poor then fertilize your plants monthly with liquid manure or compost tea. Most soil types provide ample nutrition for your Cornflower. If you’d like to give them a boost, apply some compost or a balanced slow-release fertilizer before planting seeds. Every month or two spread some compost around the base of your Cornflower plants. This provides lots of nutrition and guarantees you’ll have plenty of flowers throughout the year.

Feed Cornflower plants once per month during the spring and summer months using a balanced flower fertilizer. Refer to the manufacturer’s instructions for proper dosage, and then apply half the recommended dose. The Cornflower plant can be invasive if the soil is too fertile, so avoid over-fertilizing.

Cornflower Plant Care

  • Very little special container care for Cornflower is necessary. One of the biggest tips for growing Cornflower in containers is to keep the soil a little on the dry side. Fertilize container Cornflower plants with water-soluble plant food once per month.
  • Cornflower should be deadheaded for best appearance. There are only a few pests that bother the Cornflower plants and disease is confined to fungal issues which are easy to prevent by monitoring water usage.
  • When growing Cornflowers in containers, be prepared for a short but glorious season. These wildflowers are mostly present in the spring and early summer seasons except the perennial forms.
  • Water your plants once weekly or when the top 6 inches of soil begins to dry.
  • Cover the soil around the plants with a 2-inch layer of mulch to help retain soil moisture and then keep back weeds.
  • Pinch off dead flowers carefully once or twice weekly during the blooming period.
  • Monitor the Cornflower plants for fungal growth that indicates mildew problems or red splotches that indicate rust. Trim off infected plant leaves, and destroy badly infected plants to prevent the spread of these diseases.

Cornflower Plant Growing Problems

Cornflower plants are generally a very healthy and hardy plant when cared for properly. The Cornflower plants can become susceptible to molds, rusts, and mildews if the plants receive too much water and not enough air circulation and sunshine. They are prone to wilting in drought conditions.

Very few pests will bother Cornflower plants. Some types of aphids take up residence on or under leaves. These can be wiped out by applying neem oil on all plant surfaces and the oil smothers eggs and kills the adults.

Mealybugs are another sucking insect that may snack on your Cornflower plant. While Cornflower plants are not their first choice, they still may be at risk. Use insecticidal soap to end their stay.

In addition to these, rabbits will nibble on the leaves of your plants. They may also help get rid of caterpillars or other pests, so consider them to be helpful. Many beneficial insects are drawn to the flowers and ladybugs will help to eliminate aphids. Pollinating insects such as bees will make a garden thrive. Very few diseases will cause damage to your Cornflower.

Getting rid of powdery mildew disease can be a slow process. Neem oil works well but takes multiple applications. Weekly sprayings will reduce the chances of powdery mildew disease or pest infestation. Spread by wind-borne spores, rust also appears. This fungal disease causes yellow or white spots on top of plant leaves. Over time, spores appear on the underside of the leaves and the plant’s growth becomes stunted.

When and How to Harvest Cornflower

Cornflower makes good cut flowers. When harvesting the Cornflower blossoms, cut them just before the buds open for a longer-lasting display. By using sharp scissors, harvest a full stem, which will encourage new growth to sprout from the base of the plant.

Commonly Asked Questions about Growing Cornflower

Do Cornflowers need full sun?

Cornflower plants like to grow in well-drained soil in full sun.

Are Cornflowers annual or perennial?

Cornflowers are extremely colorful hardy annuals.

Where do Cornflowers grow best?

Cornflowers grow and flower best in sunny positions.

Can you transplant Cornflower seedlings?

If you start Cornflower seedlings indoors, you should transplant them to their permanent garden bed before they grow to more than 4 inches tall. Only, transplant after frost danger has passed. Cornflower plants require moist but well-drained soil and full sunlight to perform their best.

How long does it take Cornflower to grow?

Cornflower plants are a pretty quick flower, having just 65 days for growing from seed to bloom.

How often should you water Cornflower plants?

Water Cornflower plants once weekly or when the top 6 inches of soil begins to dry.

In case if you are interested in this: Growing Organic Spinach At Home.


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