Growing sunflowers in Idaho is an incredibly rewarding experience! Idaho offers a wide variety of climates and soils, making it the perfect place to cultivate these vibrant and beautiful flowers. With plenty of sunshine and ample rainfall, sunflowers grow strong and tall in Idaho’s fertile ground.
Sunflowers are extremely drought tolerant and require minimal care, so they are easy to maintain. From the bright yellow petals to the dark center, sunflowers bring beauty and life to any garden or landscape. With the right care, Idaho sunflowers can be a showstopper in any landscape!
Idaho’s climate and growing zones
Zone 3 is located in the far northern part of the state and is generally cooler than the other zones. The average annual low temperatures range from 0-10°F, while the average annual high temperatures range from 40-50°F. This zone is best suited for hardy trees, shrubs, and perennials, as well as cold-tolerant vegetables like kale, beets, and spinach.
Zone 4 is located in northern and central Idaho, and is slightly warmer than zone 3. Average annual low temperatures range from 10-20°F, and average annual high temperatures range from 50-60°F. This zone is best suited for trees and shrubs like junipers, conifers, and maple trees. Additionally, vegetables like lettuce, broccoli, peas, and beans can thrive in this zone.
Zone 5 is located in the southern parts of central and eastern Idaho. Average annual low temperatures range from 20-30°F, while average annual high temperatures range from 60-70°F. This zone is best suited for a variety of trees, shrubs, and perennials, as well as vegetables like peppers, tomatoes, and squash.
Zone 6 is located in the southernmost part of Idaho, and is the warmest of the four zones. Average annual low temperatures range from 30-40°F, and average annual high temperatures range from 70-80°F. This zone is best suited for trees, shrubs, and perennials that can handle warmer temperatures, like magnolias, dogwoods, and hibiscus. Vegetables like corn, cucumbers, and okra can also thrive in this zone.
Zone 7 is located in the southwestern corner of the state and is the warmest growing zone of the four. Average annual low temperatures range from 40-50°F, and average annual high temperatures range from 80-90°F. This zone is best suited for trees, shrubs, and perennials that can handle hot temperatures, like palms, yuccas, and cacti. Additionally, vegetables like cucumbers, sweet potatoes, and summer squash can thrive in this zone.
Growing sunflowers in Idaho
Growing sunflowers in Idaho can be a rewarding experience, but there are a few things to consider before planting. Idaho is known for its cold climate and long winters, making it difficult to successfully grow sunflowers in the state. Sunflowers need warm temperatures and plenty of sunshine to thrive, so planting them in the spring when temperatures are still cold can be a challenge.
Idaho’s climate can also be unpredictable and extreme, with hot summers and cold winters. During the summer months, temperatures can reach into the 90s, making it ideal for sunflowers to thrive. However, the cold winter months can be difficult, with temperatures usually dipping below freezing. Sunflowers are very sensitive to cold temperatures and can be killed if exposed to frost. For this reason, it is important to plant sunflowers in the spring when temperatures are still mild, and the days are getting longer.
In addition to planting in the spring, it is also important to provide plenty of sunlight and water to your sunflowers. Sunflowers need at least 6-8 hours of direct sunlight each day to grow and bloom properly. Additionally, regular watering is important to ensure the soil is moist and not too dry.
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 Idaho
Sunflower seeds should be started indoors 4 weeks before your final frost date. In Idaho, 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 Idaho
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 Idaho
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!