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How to grow sunflowers indoors

Sunflowers are a beautiful addition to any garden. However, they can also be grown indoors given the right conditions. They will brighten any home and bring a sprinkle of summer to any room in your house. They can also produce a head full of tasty seeds and as they are easy to grow annuals, they can be replanted every year by using the seeds from the previous year’s harvest. Because of their nutritional value, the indoor sunflowers are widely favored by organic food lovers.

How to Start

Sunflower 1

Sunflower 1. Photo by Forest Wander

First step in growing sunflowers indoors is deciding which variety suits your needs the best. As not all varieties produce seeds, you may have to determine if you want to grow them for their beautiful appearance only or for their nutritional attributes. Many avid gardeners select the dwarf kind of sunflowers because of their compacted size and ease of care. The dwarf variety typically grows to less than two feet tall and produces bright yellow flowers with dark centers. Some of these types of sunflowers produce edible seeds. They are a natural source of Vitamin E and B and are often used in salads.

Types of Indoor Sunflowers

Sunflower 2

Sunflower 2. Photo by Sakeeb Sabakka

Many flower lovers prefer the dwarf varieties of indoor sunflowers due to the ease of cultivation and care. The most common types include the following:

• Teddy Bear – Produces 1-foot plants with orange and yellow petals. It begins to bloom with one 4-inch main flower and expands with additional 4-6 surrounding flower heads.
• Big Smile – Grows up to eight inches in height, and it produces a single flower with yellow petals and black center.
• Pacino – Reaches the height of two feet and produces a cluster of flowers with yellow petals and yellow center.
• Jade – The tallest of the dwarf variety, the Jade can reach the height of 4 feet. It blooms quickly with greenish petals and cream-colored center. They are typically used for flower arrangements as they do not produce edible seeds.
• Valentine- This branching variety has pale yellow petals and light center. It may grow up to 3 feet tall.

The Seeds

Sunflower Seeds

Sunflower Seeds. Photo by Valdemar Fishmen

The sunflower seeds need plenty of warmth and sunshine to germinate. The temperature of the soil must be maintained at 70-75 degrees during the germination period, and it should never be allowed to fall under 65 degrees. They should be planted in seedling trays and placed in the sunniest spot in your home. You should see the first leaves appear in about one week, and growth is typically rapid afterwards if the container is placed in front of south-facing window. If the amount of light is not sufficient, it can be supplemented by fluorescent lighting specifically designed for seed germination. It is important not to change the location until the plant is well established, at which point, it can be replanted into a bigger pot with a wide bottom. If the new plant becomes too leggy with poorly developed leaves, it may have to be discarded as it will never grow to its proper size or produce any seeds. It is also a sign that the plant is too cold, and it is has reached the stage of its collapse.

Transplanting the Sunflowers Outdoors

Many people choose to transplant the taller varieties of sunflowers outdoors once the weather becomes warm enough for the plant to flourish. The seeds typically attract wildlife such as squirrels and birds. If the plant remains in the pot, the top layer of soil can be protected by wire mesh. If the sunflower is transplanted directly into the ground soil, the top layer can be covered with moss or gravel to minimize the invasion of wild animals.

Sunflowers also do not thrive in windy locations. They prefer calm and bright locations illuminated by sun throughout the day. They blossom vigorously when planted against the fence or when supported by stakes. Sunflowers are “social” plants and like to be planted within close proximity to each other. They can later be thinned out if they become too crowded.

Growing Period

Sunflower 3

Sunflower 3. Photo by Moyan Brenn

Once the seeds or seedlings are planted, the sunflowers will have to be watered every 1-2 weeks, letting the soil dry in between the watering. In nature, ordinary rainfalls are sufficient enough to help the sunflowers develop to their natural height and shape. Indoors, they have to be watered regularly mimicking their natural environment.

When the plant reaches the height of two feet, it should be supported by a stake anchored to a structure outside the container. The stakes should never be placed directly into the pot as they may damage the root system. In addition, by this stage of growth, the sunflower heads become massive and become too heavy for the stem to hold its weight. For the plant to keep growing, it is imperative to provide it with additional support. If the plant is grown only for its flowers, the tips can be periodically pinched back to encourage bushier growth and rapid explosion of additional flower heads.

Pot and Containers

The seeds or seedlings best germinate in small 12-16 inch pots. Sunflowers prefer the stability of the same container and soil mixed with organic matter, and they do not like to be removed from one location to another. It is recommended to plant one seed per pot. When the plant matures, it can be transferred once during the season to a bigger container with plenty of room for roots to spread. The plant will have to be watered more frequently as sunflowers are thirsty feeders and need additional nourishment if grown indoors.

Diseases and Pests

Sunflower 4

Sunflower 4. Photo by Anthony Quintano

Naturally grown sunflowers are prone to acquiring several plant diseases. When grown outdoors, they fall prey to caterpillars and grasshoppers. Their bright yellow petals captivate the attention of many types of worms as well as birds. However, indoors, the danger of becoming infested is minimized and indoor sunflowers typically do not need any special attention or pesticides making it safe for all occupants of the household including children and pets. Keeping your sunflower in a sunny location throughout the season will also avoid the growth of mildew or fungus.

End of Season

At the end of the summer, the petals begin to fall, and the plant starts to wilt. If you grow indoor sunflowers for their seeds, the best method for harvesting them is to let the plant die on its own. As this technique is not the most attractive, the plant can be moved to another location as long as it stays warm until the seeds reach their edible size. The stem can also be cut and hung upside down for better ventilation. Once the plant is harvested, some of the seeds can be retained to be replanted the following year, and the remainder of the plant should be discarded as it will not re-grow on its own again.

Summary of the Preferred Conditions for Indoor-grown Sunflowers

Sunflower 5

Sunflower 5. Photo by Rachel Samanyi

• Plant the seeds or seedling in a well fertilized soil that has been cultivated about 12 inches deep. Incorporate organic matter such as compost.
• Water regularly throughout the growing season, and cover the top layer of soil with mulch or gravel not touching the stem and allowing proper ventilation.
• Place the containers and pots in a sunny area of the house facing the south. Minimize transfer of the pots from one location to another.
• If growing more than one sunflower, place the containers closely together, and set them apart as the plants become bushier.
• Weeding and pest control is not necessary when growing indoor sunflowers.
• Apply mild fertilizer around the base of the plant throughout the season in regular 2-3 week intervals to promote healthy growth.
• Stabilize and support the plant once it reaches the height of two feet. Place the stakes behind the plant and secure them to on outside-the-pot structure such as the wall or another planter.

Sunflowers can withstand long periods of drought, but grow best when watered and maintained regularly. They make a wonderful addition to other plants in your house and provide plenty of shaded protection for low growing plants in your house. They generally serve as a background to other container plant and flower arrangements, and they thrive in the company of other plants.

The seeds can be stored in air-tight containers during the winter and used for consumption or can be replanted the following season indoors or outdoors. The sunflowers originated in Western United States, and now can be grown and cultivated in all temperature zones throughout USA and Canada.

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