This Is How To Grow Sunflowers And See Your Garden Bloom

You may already know how to grow roses, thyme or even saffron, but no plant can beat the feeling that sunflowers (Helianthus annuus) give you. Even though it’s a plant, it gives a radiating smile that affects even the saddest person on earth. Its name, sunflower, is from the French word, tournesol, which means turns with the sun. 

Sunflowers at sunrise

Their seeds can serve as healthy snacks, while you can use their oil for cooking. They also help to absorb toxins in the body. Sunflowers are one of the easiest plants to grow, and they are highly pest-resistant. If you wish to grow this plant in your garden, this article will guide you.

Where to grow sunflowers

Sunflowers are so-called for a reason – they need sun and even give off a sunlike appearance with their beautiful, golden yellow petals. They were first domesticated by Native Americans for cooking, healing and making clothes.

When it comes to growing sunflowers, you need to plant them where they can get direct sun, at least 6 – 8 hours daily. Also, these lovely plants thrive best in fertile soil located in a sheltered place, as well as in containers and pots. Plant your sunflowers in a spot that can shelter them from strong winds and well-draining soil that will not water-log after it rains. 

Due to their long tap roots that need sufficient space to spread out, the soil of sunflowers must not be too compact. Hence, in making a bed, ensure you dig a deep hole of about 60-90 cm and 90 cm across. A somewhat alkaline soil with a pH of 6.0 to 7.5 will also aid their growth. 

Sunflowers come in different varieties, including dwarf sunflowers and giant sunflowers. Others come with bright yellow flowers, deep red flowers, and white flowers.  

A child in front of sunflowers

When to plant sunflower seeds

Aim for March, April or May to plant as this is the best time for sunflower seed varieties. To be extra sure, ensure you check the seed packet

Ensure you place the seeds individually in smaller pots or tins of about 10 cm. Then transplant seedlings to a bigger pot in the garden after eliminating all frost risks from early June. Be sure the pot is deep enough to accommodate their taproot.

If you can be patient enough, your sunflowers will germinate in multiple folds when the soil temperatures are around 21° to 24°C. But if you need to sow sooner, you can go with soil at a temperature of 13°C. That will protect the plants from critters and other pests. 

How to plant sunflowers

Like other tap roots plants, sunflowers grow best when you sow them directly into the ground or garden. The ground provides them with enough space and time to spread their taproots.

Here are the things you need when planting sunflowers:

  • Sunflower seeds
  • Seed tray
  • Plant labels
  • Multi-purpose compost
  • Waterproof marker pen

Step-by-Step Process For Planting in a Seed Tray

So are you ready? Follow the steps below and see your garden flourish!

Young sunflowers plants grow in the seed tray

  • Put some seeds in the seed tray with some multi-purpose compost.
  •  Add one seed per hole and push it 1.5 cm down gently into the compost. For small sunflowers, sow seeds about 15 cm apart, while for giant sunflowers, sow seeds 60 to 90 cm apart as good spacing ensures stable growth.
  • Add more compost and then moisture well.
  • Then, add a plant label for proper identification of what you’ve planted.
  • Ensure you cover the pots with a clear plastic bag.
  • Place the tray in a place where direct sunlight reaches, preferably the windowsill.
  • After the sunflower seedlings have germinated and grown up to 4 cm, keep them well-moisturized until they are ready to move into a separate pot, which will be at the end of May. 
  • Prepare the pot by adding a small amount of your compost. Then, carefully remove each seedling from the tray and transfer it into the new pot.
  • Fill the pot with more compost and gently push it down to secure the seedling. 
  • Add enough water and plant labels.
  • Place them in a warm, bright location.
  • You can then start to add water-soluble fertiliser twice a week to boost the seedlings’ growth.
  • Once your plants have reached 25 cm in height, it is time to plant them in the garden or transfer them to a bigger pot.

Note: Direct-sowing is more recommended than transplanting as sunflowers don’t like to have their roots disturbed.

Planting Sunflowers in the soil

Easy right? Now, let’s move on with the whole planting process. Check the steps below:

Human hand planting young sunflowers in the garden

  • Prepare your garden or yard by removing weeds and adding plenty of organic matter to nourish the sunflowers and promote strong root growth.
  • Dig a shallow hole of about 2 cm deep and gently place the seeds inside. If you prefer small flower heads, plant the seeds 4-8 cm apart, or plant 12-15 cm apart for larger heads. This measurement is important to have uniformed heads.
  • Carefully place the seed individually into the holes and cover it with soil. 
  • As the seedlings grow, thin the plants out, so they’re around 45-75 cm apart. 
  • Watering plants the right way is always important. Water well and stake plants with a bamboo cane to support the stem to grow straight.
  • To avoid birds scratching over the seeds, spread a large net over the planted area until seeds germinate.

How to take care of sunflowers

1. Water

Sunflowers need regular watering to grow healthy, so water deeply around the root spot, about 7 to 10 cm from the plants when they are small. 

After your sunflower plants have grown, moisture your plant at least twice a week but not frequently to encourage deep and strong rooting.

2. Fertiliser

Feed your plants sparingly as over fertilisation can cause their stems to break off easily. It will help if you use diluted or slow-release granular fertiliser to encourage larger flowers. 

When applying the fertiliser, be careful not to add it to the plant’s base. Else, it may build a moat in a circle around the plant. Also, feeding your plant with tomato feed can help in flowering and give you tall sunflowers.

Young woman is taking care sunflowers in her garden

3. Light

Sunflowers are generally known to be a big advocate for high temperature. Hence, you will be helping them grow well if you place your flower pots in a sunny location or plant them in an area that gets at least six to eight hours of full sun every day.

4. Temperature

Windy temperature is not ideal for sunflowers as it may trip them over, especially when they have grown tall.

Sunflowers can handle a bit of chilly weather, but they need good air circulation to prevent root rot and other diseases. Aim to grow sunflowers between 21 and 25 degrees Celsius when the risk of frost has passed.  The tall varieties find it hard to recover if they dry out.

5. Soil

Sunflowers can survive tremendously in any soil – poor or dry. However, you will get the best when you plant them in well-drained soil that contains a sufficient amount of organic matter.

Propagating sunflowers

You can propagate sunflowers by cutting and rooting them. The most straightforward method is collecting some of the seeds, drying them, and saving them for planting the following season. 

The flowers should begin to grow in the early fall. When this happens, the sunflower heads will turn downward, and the florets in the centre will shrink. The only way you can know if the seeds are ready for harvest is to pick some and open them. If the seed kernels are plump, they’re ready for harvesting.

Pinching out the growing tips of sunflowers is a technique used to encourage new stems to grow on plants.  This is the part that allows the plant to grow to a tall height you’d like. Pinching also helps to accelerate the growth of sunflowers.

Sunflowers seeds and flowers on wooden table

Harvesting Sunflower Seeds

To harvest, cut the flower head with some part (2 cm) of the stem, and hang it in a warm and dry place away from insects and rodents. 

Place a plastic bag over the seed heads to keep the seeds intact. Ensure you perforate the paper bag to allow ventilation. When the seeds are completely dry, scrape them off the flower head and collect them in a tray. 

Select some of the largest, more rotund seeds with the potential of germinating well.  Clean the seeds well, and store them in a dry, cool location until the next planting season.

Common pests and diseases for Sunflowers

  • Squirrels and Birds

Squirrels and birds love sunflowers for their seeds. To avoid this, cover the heads with a piece of cheesecloth or paper bags after the seeds start to develop. 

You can also distract these animals by providing corn in another location close to your sunflower plants.

  • Cutworms

Cutworms are moth larvae that eat the foliage, creating holes in young leaves and making young plants wither, leading to their eventual death. 

Cutworms hang out during the day, which is the best time to get rid of them. You can do that by handpicking them or introducing nematodes.

  • Grasshoppers

Although they do not damage the entire plant, grasshoppers take their shares from sunflowers by chewing their foliage and the seeds. You can use a grasshopper pesticide that doesn’t destroy the plant.

Beetle sits on a sunflower

  • Sunflower Beetles

Sunflower beetles have a reddish-brown head and a creamy, striped body. Despite their small body, they can cause permanent damage to your plants.

They harm sunflowers by eating through their foliage till the last flesh. Once you notice them early, repel them with insecticidal soap or neem oil.

  • Alternaria Blight

If you notice your sunflower foliage suddenly develop yellow-ringed black spots or the stems develop dark streaks, they may be suffering from Alternaria. The disease is a fungus that affects leaves, stems, and flower heads

To prevent this, avoid overhead watering and ensure there is ventilation among your plants. 

  • Rhizopus Head Rot

The signs of rhizopus head rot include black spots and spores on the backs of your sunflower heads. If you don’t take care of it on time, it may spread to other plants. 

Other things that affect the plant include mildew and is easily treated with a general garden fungicide. 

Sunflower varieties

  • Mammoth Russian

This sunflower cultivar can grow really tall and features large sunny heads. It offers easy-to-crack shells and plumpy seeds for snacks. 

Flowers bloom two months after planting, and you start harvesting seeds in the next three to four weeks.

  • Wild Sunflower

This plant boasts of beautiful long bouquets. You’ll have mature wild sunflowers in your garden within four or five weeks in the spring. Two months after sowing, you can have a blooming that makes you cheerful.

Velvet queen sunflower

  • Velvet Queen

If you think sunflowers only come in yellow colour, you are wrong. This breed comes in mahogany colour, which instantly makes you crave a red velvet cake. To beautify your garden, you can mix this cultivar with other types.

Sunflowers are inviting and beautiful to behold. They provide edible seeds that are healthy and help remove harmful toxins from the body. There is no reason not to have sunflowers in your garden. So, are you ready to give it a go?

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