How to Plant Turing Sunflowers

Preparing Your Planting Bed

Choose an area that gets 6-8 hours of direct sunlight. As their name suggests, sunflowers love the sun! They even grow to face it. Your sunflowers will enjoy a sunny spot in your yard where they can soak up the rays they need to thrive.

Use a loose, well-draining soil. Sunflower roots are long and tend to stretch deeply into the soil. However, they can’t do that in compact soil. Make sure your soil is well aerated. If you’re using the soil that’s already in your yard, dig 2 feet down into the ground across your entire planting bed. Break up all of the soil using your hoe or shovel. You could also use an aerator, which you could buy or rent from a home improvement or gardening store.

Make sure the area drains well. The sunflowers will grow best in an area where the water drains away quickly. Check the area where you want to plant after it rains to look for pooling water. A well-draining area will not have excess standing water. You could also spray water over the area and watch what happens. If the water drains away, then the spot is likely good for sunflowers.

Check the pH of your soil. The ideal pH for growing sunflowers is between 6.0 and 7.5. However, they’re also a hardy plant that can thrive even in less than ideal conditions. If your soil pH is not desirable, you may want to amend your soil. If you want to lower the soil pH, you can add elemental sulfur, aluminum sulfate, iron sulfate, acidifying nitrogen, sphagnum peat, or an organic mulch. If you want to raise the soil pH, you can add limestone, hydrated lime, or wood ash to the soil.

Shelter your plants from strong winds. Sunflowers are tall, which makes them more susceptible to wind. Strong wind can damage the stems of your growing sunflowers, causing them to break. If you can, plant them near a wall or fence so that they’ll be safer from the wind. You could install a lattice or other planting support feature behind the sunflowers.

Choose a large, heavy container if you’re using a pot. Sunflowers can be grown in pots, though the ground is better. Use a deep container or planter, and make sure it is weighed down. As the sunflower grows, it can tip the pot. Stone and terracotta pots can be a great option, as they are heavier.

Sowing Sunflowers

Wait until after the last spring frost. Cold weather isn’t good for sunflowers. In fact, they grow best if you wait until the temperature is steadily above 55 °F (13 °C). In most areas, the best time to plant sunflowers is between mid-April through May. Alternately, you can start your sunflowers off in a pot indoors in the early spring and then move them outdoors in late spring once all risk of frost is over.

Place the sunflower seeds directly into the soil 1 inch (2.5 cm) deep. Sunflowers grow best in the ground. You’ll want to bury them a little since the seeds are very tempting to birds. It’s a good idea to plant 2 seeds in the same spot, as not all of them will sprout. Don't worry about crowding because you’ll be thinning them later anyway. You can find seed packets at most gardening stores or online.

Space the seeds 6 inches (15 cm) apart. This is a good distance between your seedlings and will increase your chances of success. Although it’s too close for mature sunflowers to thrive, some of your seeds and seedlings will likely get eaten by scavengers or die of other causes.

Add a fertilizer to encourage root growth. Strong, deep roots can help the sunflower thrive, especially as it gets taller. If the roots don’t grow well enough, the plant won’t be strong enough to stay in the ground as it keeps growing. Fertile soil can provide the nutrients needed for the root system to grow strong. If you’ve just fertilized the soil before you planted the seeds, then you do not need to add anymore fertilizer at this time. The best way to fertilize sunflowers is by using a diluted liquid organic fertilizer.

Thin the plants when they are 6 inches (15 cm) tall. Make sure that each plant has about 1 foot (0.30 m) of space on either side. Try to save the blossoms that appear to be thriving the best, pulling the extra flowers that are growing nearby.

Cover the plants in a thin netting if birds are a concern. Birds might see your budding sunflowers as a delicious snack. Unfortunately, they could munch on all of your plants before they have a chance to grow. You can prevent this by covering the seedlings with a thin netting, such as a cheesecloth. Remove the netting once the flowers are fully established. You’ll know the flowers are fully established when they have progressed past being a seedling. A good time to remove the netting is when you thin out the plants. Once the sunflowers have seeds, you’ll likely have birds snacking on them again. Although this is frustrating, it could cause some seeds to scatter and grow new flowers!

Caring for Your Sunflowers

Fertilize the sunflowers once a week. Sunflowers are heavy feeders, but they also have deep roots that make the best of available nutrients. Since it’s easy to over-fertilize them, it’s best to use a diluted organic fertilizer. Simply add the fertilizer to the plants’ regular watering. You could use a slow-release fertilizer that ensures a continuous release of nutrients into the soil.

Give your tall sunflowers some support. Drive a tall, sturdy garden stake or cane into the ground near your sunflower. Then tie the flower to the stake. Although this is optional, it will help your flower stand tall as it continues to grow. You may want to add another tie in another place further up the stem as the flower grows. This will prevent your sunflowers from flopping over.

Water your sunflowers once a week. You should water 3-4 inches away from your seeds or seedlings. Once the plants begin to thrive, however, you should water them thoroughly directly over the plant. Keep in mind that the roots are deep, so you’ll want to provide lots of water during your weekly watering. If it’s been very dry or very wet, it’s a good idea to alter your watering schedule. Feel the soil to see if it feels dry or wet. Provide extra waterings if the soil feels dry, but delay your watering if the soil feels wet.

Protect your sunflowers from pests. The biggest threats to sunflowers are birds and squirrels who want to snack on the delicious seeds! You can protect your plants with netting or by covering the flower with white polyspun garden fleece. Luckily, sunflowers aren't prone to insects. If you live in an area with a lot of deer, then you may want to put a deer-proof fence around your yard. Deer also enjoy eating sunflower seeds.

Joining the Turing Experiment

Grow your sunflower to full maturity. You will need a mature flower head to examine. It’s a good idea to cover your sunflower in a net or white polyspun garden fleece, as you’ll need as many seeds intact as possible to do a count. Sunflowers usually don't reach full maturity until late summer or early fall.

Photograph the head of the flower. Take a close-up photo of your flower head. Make sure that you have a clear view of the seeds. Then print out your photo. You can also cut the flower head and use it for your experiment instead of the photo.

Count your seeds using the photo. It’s easier to count the seeds on the photo than on the flower. Start by doing a clockwise count of the seed spirals. Write that number down, then start again. This time, do a counter-clockwise count. Document this number, as well. You can use this official counting guide provided by the Turing research project: http://webarchive.nationalarchives.gov.uk/20170404145538/http://www.turingsunflowers.com/measure/howto

Input your counts into the official Turing sunflower data sheet. This will help you identify if your flower contains a Fibonacci sequence! While many sunflowers do, not all sunflowers will. Although the official study is over, you can still get your very own data sheet here: http://webarchive.nationalarchives.gov.uk/20170404150818/http://www.turingsunflowers.com/media/Resources/count/Measure_and_count.pdf