Growing sunflowers in Colorado can be a truly rewarding experience! With its mild summer temperatures and plenty of sunshine, Centennial State is an ideal place to grow sunflowers. Sunflowers are incredibly easy to grow, making them a great choice for novice gardeners and experienced green thumbs alike.
With their bright and cheerful blooms, sunflowers can bring a splash of color to any garden. Plus, their seeds are a nutritious snack and their oil is a great cooking ingredient. With so many benefits, it’s no wonder that sunflowers are such a popular choice for Colorado gardeners!
Colorado climate and growing zones
Colorado is a diverse state with climates ranging from hot deserts to high mountain ranges, with many growing zones in between. In general, the state has a semi-arid climate, with mild winters and warm summers. Growing Zones 3 through 7 represent some of the most diverse and productive growing areas of Colorado.
Zone 3, located in the northern and central part of the state, has cold winters and short growing seasons.
Zone 4, located in central Colorado, has mild winters and longer growing seasons.
In Zone 5, located in the southern part of the state, has hot summers and longer growing seasons.
In Zone 6, located in the western part of the state, cold winters and hot summers create somewhat challenging conditions for growing.
Zone 7, located in the western and southern parts of the state, has hot summers and mild winters, making it an ideal location for a wide variety of crops.
Growing sunflowers in Colorado
Growing sunflowers in Colorado can be a rewarding experience. Sunflowers thrive in warm climates, so Colorado’s cooler temperatures can make growing them more difficult. However, with the right soil, plenty of sun, and diligent care, it is possible to make sunflowers grow in a Colorado climate.
The key to growing sunflowers in Colorado is to choose a variety suited to the climate. Sunflowers are available in many different sizes and colors, so finding one that can withstand cold temperatures is important. Look for sunflower varieties that are bred for cold climates and are winter-hardy. In order to thrive, sunflowers need plenty of sun.
The best time to plant sunflowers in Colorado is in the spring when days are long and the sun is strong. Choose a spot that gets at least 6 hours of direct sunlight per day. The soil in Colorado can be rocky and dry, so it’s important to ensure your soil is well-draining and has plenty of nutrients. Adding compost or other organic matter can help create a healthy soil environment.
Sunflowers do best in soil with a pH of 6 to 8. When it comes to watering, it is important to keep your sunflowers well-watered. However, it is important to avoid over-watering, as sunflowers are susceptible to root rot. Aim to water your sunflowers once a week, or more in hot weather.
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 Colorado
Sunflower seeds should be started indoors 4 weeks before your final frost date. In Colorado, the final frost dates are:
- Zone 3: Around May 15th
- Zone 4: Around May 12th
- Zone 5: Around April 30th
- Zone 6: Around April 21
- zone 7: Around April 3
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 3: Around April 17th
- Zone 4: Around April 14th
- Zone 5: Around April 1st
- Zone 6: Around March 24th
- zone 7: Around March 6th
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 Colorado
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 Colorado
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!