Growing sunflowers in Utah is a great and rewarding experience, especially in the summer months when the sunflowers are in full bloom. Sunflowers, a symbol of cheerfulness, are native to Utah and they thrive in the warm and sunny climate of the region. Sunflowers require minimal maintenance, yet they produce a beautiful and vibrant display of colors that can last for months.
They also attract beneficial insects, birds, and other wildlife to your garden. Not only are they aesthetically pleasing, but they can also be used to produce sunflower oil, sunflower seeds, and even sunflower-infused beverages. With the right amount of sunshine and water, Utah’s sunflowers can bring a smile to anyone’s face.
State climate and growing zones
Zone 4a has cold winters, with average annual minimum temperatures of -30 to -20 degrees Fahrenheit. This zone is mainly found in the higher elevations of the northern regions of the state. Winters are very cold, with snowfall occurring throughout the winter. Summers are short and cool, with average maximum temperatures ranging from 70 to 80 degrees Fahrenheit. The growing season is short, with the last frost date occurring in mid-June and the first frost date in mid-September. This zone is best suited for perennial shrubs, evergreen trees, and cold-hardy vegetables.
Zone 5a is slightly warmer than Zone 4a, with average annual minimum temperatures ranging from -20 to -10 degrees Fahrenheit. It is found in the higher elevations of the central and northern regions of the state. Winters are cold, but not as extreme as Zone 4a, and snowfall is common. Summers are short and cool, with average maximum temperatures ranging from 70 to 80 degrees Fahrenheit. The growing season is slightly longer than Zone 4a, with the last frost date occurring in late May and the first frost date in mid-October. This zone is best suited for perennial shrubs, evergreen trees, and vegetables that are a bit more cold-hardy.
Zone 6a has moderate winters, with average annual minimum temperatures ranging from -10 to 0 degrees Fahrenheit. It is found in the higher elevations of the central and southern regions of the state. Winters are cold but not extreme, with occasional snowfall. Summers are warm, with average maximum temperatures ranging from 80 to 90 degrees Fahrenheit. The growing season is longer than in Zones 4a and 5a, with the last frost date occurring in late April and the first frost date in mid-October. This zone is best suited for a variety of perennials, evergreen trees, and vegetables that can tolerate mild frosts.
Zone 7a has mild winters, with average annual minimum temperatures ranging from 0 to 10 degrees Fahrenheit. It is found in the lower elevations of the central and southern regions of the state. Winters are mild, with occasional snowfall. Summers are very warm, with average maximum temperatures ranging from 90 to 100 degrees Fahrenheit. The growing season is significantly longer than in the other zones, with the last frost date occurring in mid-April and the first frost date in late October. This zone is best suited for a variety of warm-season vegetables, perennials, and evergreen trees.
Growing zones 8a and 9a
Zone 8a has subtropical winters, with average annual minimum temperatures ranging from 10 to 20 degrees Fahrenheit. It is found in the lower elevations of the southern and western regions of the state. Winters are mild to warm, with little to no snowfall. Summers are hot, with average maximum temperatures ranging from 100 to 110 degrees Fahrenheit. The growing season is very long, with the last frost date occurring in early April and the first frost date in late November. This zone is best suited for subtropical vegetables, perennials, and evergreen trees that can tolerate high temperatures.
Zone 9a has tropical winters, with average annual minimum temperatures ranging from 20 to 30 degrees Fahrenheit. It is found in the lower elevations of the southern and western regions of the state. Winters are mild to warm, with little to no snowfall. Summers are very hot, with average maximum temperatures ranging from 110 to 120 degrees Fahrenheit. The growing season is extremely long, with the last frost date occurring in late-March and the first frost date in late December. This zone is best suited for tropical vegetables, perennials, and evergreen trees that can tolerate extreme temperatures.
Growing sunflowers in Utah
Growing sunflowers in Utah can be a challenge due to the cold climate. Despite the cooler temperatures, it is still possible to successfully cultivate sunflowers in Utah. Utah experiences cold winters and moderate summers, and the temperature rarely gets too hot for sunflowers to thrive. The best time to plant sunflowers in Utah is during the spring months of April and May. This is when the soil has warmed up enough to give the sunflower plants the best chance for successful germination.
When planting sunflowers in Utah it is important to use soil that is well-drained and has plenty of organic matter. Sunflowers prefer full sun, so it is important to find a location where they will receive plenty of sunlight throughout the day. It is also important to water the sunflowers regularly, especially during dry periods.
When it comes to harvesting sunflowers in Utah, it is important to be mindful of the cold climate. Sunflowers are best harvested at the end of the summer when they are dry and the seeds are mature. If temperatures drop before the sunflower plants are dry, it is important to harvest them quickly and store the seeds in a cool, dry place until the temperatures warm up again.
Some of my favorite varieties of sunflower include:
- Mammoth Grey Stripe Sunflower (Helianthus annuus) – 75-100 days to maturity
- Teddy Bear Sunflower (Helianthus annuus) – 60-90 days to maturity
- Red Sun (Helianthus annuus) – 65-95 days to maturity
- Autumn Beauty Sunflower (Helianthus annuus) – 75-90 days to maturity
- Lemon Queen Sunflower (Helianthus annuus) – 75-95 days to maturity
- Velvet Queen Sunflower (Helianthus annuus) – 90-110 days to maturity
- Dwarf Sunspot Sunflower (Helianthus annuus) – 60-90 days to maturity
- Giant Sungold Sunflower (Helianthus annuus) – 85-110 days to maturity
- Evening Sun Sunflower (Helianthus annuus) – 75-95 days to maturity
- Sundance Kid Sunflower (Helianthus annuus) – 75-95 days to maturity
When to start sunflowers indoors in Utah
Sunflower seeds should be started indoors 4 weeks before your final frost date. In Utah, the final frost dates are:
- Zone 4: Around May 12th
- Zone 5: Around April 30th
- Zone 6: Around April 21
- zone 7: Around April 3
- zone 8: Around March 28th
- zone 9: Around February 28th
You should also consider the size of the variety of sunflower you are planting, as shorter varieties can be planted later and taller varieties will need to be started a week or two earlier. Sunflowers should be started indoors:
- Zone 4: Around April 14th
- Zone 5: Around April 1st
- Zone 6: Around March 24th
- zone 7: Around March 6th
- zone 8: Around February 27th
- zone 9: Around January 31st
Starting sunflowers from seed is a relatively easy process that can be done both indoors and outdoors. To begin, you will need to purchase sunflower seeds from a garden center or online. When selecting seeds, make sure to look for the desired variety you want to grow. Once you have your seeds, you can choose to start them indoors 4 weeks before the last frost date for your region.
Fill a seed tray with starter soil and moisten it with a spray bottle. Place your seeds on top of the soil, cover them lightly with starter soil, and water them gently. Place the tray in a warm and sunny spot, and keep the soil moist. Once your plants have grown 2-3 sets of leaves, you can transplant them outdoors.
Planting sunflowers outside in Utah
Sunflower seeds should be planted outdoors after the last average frost date for your area. Planting sunflower seeds too early can result in poor germination and seedling growth and potentially death if there’s a hard freeze.
When planting outdoors, make sure the area has plenty of sunshine and well-draining soil. Dig a hole that is twice the size of the root ball, and fill the hole with compost or aged manure. Place the seedling in the hole and backfill with soil, then water deeply.
For the remainder of the sunflower’s life, make sure to keep the soil moist and fertilize regularly. With proper care, you should have beautiful sunflowers in no time!
When to harvest sunflower seeds in Utah
When sunflower seeds are ready to be harvested, the back of the flower head will be dry and start to turn brown. The individual seeds will be dry and firm. The green husks surrounding the seeds will have turned yellow or white and begun to dry out. To check if the seeds are ready to be harvested, lightly pinch the seed head between your thumb and forefinger. If the husks break open easily, the seeds are ready to harvest.
Harvesting sunflower seeds is easy. Cut the flower head off the stem and spread it out on a clean surface. To remove the seeds, use your hands to rub the flower head and release the seeds. Collect the seeds in a large bowl or container. Once the seeds are harvested, store them in an airtight container in a cool, dry place. Make sure the container is well sealed to keep the seeds from going bad. Sunflower seeds can last for up to a year if stored properly.
Sunflower seeds are delicious and nutritious snack food. They can be eaten raw, toasted, or sprouted. Sunflower seeds are also used in salads, cereals, granola, and energy bars. They are loaded with essential vitamins and minerals like Vitamin E, phosphorus, magnesium, and zinc. Sunflower seeds can also be used to make sunflower seed butter, which is a great alternative to peanut butter.
In addition to being a healthy snack, sunflower seeds are also used to make birdseed. You can leave your sunflowers intact outside well after the flowers have died to give your local birds a tasty snack!