Spiral Sea Shells Crochet Pattern

With Fibonacci  Sequence

I'm obsessed with number sequences these days and figured I'd dig around a little bit into the famous Fibonacci Sequence to see how it could relate to crochet and what I could design using these numbers.

If you haven't heard of the Fibonacci Sequence before, a quick Google search will give you lots of information, but all you need to know for the purposes of this Spiral Sea Shell Pattern is that we are following the number sequence discovered by the Italian Mathematician Fibonacci. He was a "medieval Italian mathematician who wrote Liber abaci in 1202; “Book of the Abacus”, the first European work on Indian and Arabian mathematics, which introduced Hindu-Arabic numerals to Europe. His name is mainly known because of the Fibonacci sequence." (Encyclopedia Britannica) although many sources attribute this finding to earlier Indian mathematicians.

If you're not big on maths, don't worry! This is really quite simple.

The idea behind this Fibonacci Sequence is just adding 2 numbers together to get the next.

It starts like this:

1,1,2,3,5,8,13,21,…

So you add 1 + 1 to get 2, then 1 + 2 to get 3, then 2 + 3 to get 5, and so on.

What makes this sequence really special is how it shows up in nature, especially in spirals like seashells, pinecones, and even flowers. As the numbers grow, they create a natural-looking curve that feels balanced and organic as opposed to perfectly circular.

I wanted to apply this idea to crochet, so I decided to use this sequence to guide my stitches. To make this shell, I increased following Fibonacci numbers. This created a spiral that expanded gradually, mimicking the way a real seashell grows.

In this spiral seashell pattern, you'll notice the shape doesn’t just get bigger. It is also not flat. It grows in a way that feels more fluid and natural. It turned out to be a beautiful, slightly curved spiral that looks much closer to something you’d find on the beach.

How the Fibonacci Sequence works (step by step)

• Keep adding the last two numbers to get the next number

So here is how we get the Numbers we want to work with for this pattern:

• 0, 1 → starting values
• 0 + 1 = 1
• 1 + 1 = 2
• 1 + 2 = 3
• 2 + 3 = 5
• 3 + 5 = 8 - I stopped here for this pattern, but if you were to continue, these would be the numbers.
• 5 + 8 = 13
• 8 + 13 = 21
• 13 + 21 = 34
• 21 + 34 = 55
• 34 + 55 = 89
• 55 + 89 = 144 and so on...

The rule (in simple terms)

Each number is:

previous number + the one before that

Mathematically, this is often written as:

F(n) = F(n−1) + F(n−2)

Why is the Fibonacci Sequence Interesting?

When you follow this sequence of numbers, you'll get a specific spiral shape (as shown in the diagram below). This is the Fibonacci Spiral, which is made up of squares that expand using this same sequence of numbers. When you draw a curve diagonally into each square clockwise, you get this beautiful Fibonacci Spiral which you'll notice in many natural creations.

You'll start noticing the Fibonacci sequence showing up in surprising places:

• patterns in flowers, pinecones, and pineapples
• spirals in seashells
• art and design proportions
• the shape of the universe! 

If you'd like to get more detailed information on the Fibonacci Spiral, with ind-depth mathematical explanation, here's a really interesting video by "Dyslexic Artist Theory on the Physics of Time".

For the purposes of the seashells we're creating today, things will be much simpler than in this detailed video explanation. We're just going to stitch some simple crochet stitches into a spiral. I'll show you exactly what you need to do. Scroll down for the instructions.

Disclaimer: This post contains affiliate links, which means I receive a small commission, at no extra cost to you, if you make a purchase using the Start Crochet links. Please see my disclosure for more details.

Materials Needed

• DK cotton yarn in 2 contrasting colors
• Size 2.5 mm crochet hook
• Yarn needle
• Scissors

Abbreviations Used in Pattern

• MC = magic circle
• sc = single crochet
• hdc = half double crochet
• dc = double crochet
• tr = treble crochet (same as triple crochet (UK) = worked same as dc, but with 2 yarn overs to start
• inc = increase = 2 sts into the same stitch
• st = stitch
• sts = stitches
• fo = fasten off

Skill Level

Beginner

Measurements/Size

Approximate finished size: 4 cm (1.5 ")

Gauge

Not important for this project.

Notes

• This spiral is worked in continuous rounds.
• Please note that I use US crochet terms.

Spiral Seashell Crochet Pattern Instructions

Shell

R1: Start with a Magic Circle (MC). Into this MC, work 2 sc, 2 hdc, and 3 dc stitches. (7 sts total)
Note: If you don't know how to work a Magic Circle, then ch 4, sl st to join and form a circle. Then work 2 sc, 2 hdc, and 3 dc into that circle.

Pull your magic circle closed. Do not join. Continue to next instructions.

Work a dc increase into the next 5 sts. (10 sts)

Work a treble crochet increase into the next 8 sts. (16 sts)

Leave 4" tail, cut your yarn and fasten off.

Weave in your ends neatly at the back of your shell. Make sure not to pull too hard on the final stitch so as not to deform your shell.

Cut excess yarn tails.

Note: Your shell will be curved, just like a real shell. It should not lay flat.

Contour

Using a contrasting color of yarn, tie a slip knot. Remove slip knot from hook.

Make sure the front side of your shell is facing upwards, then insert your hook into the center from the front of your shell. Catch the slip knot and pull it through.

Insert your hook into the first stitch you worked, pull up a loop from behind the shell. Slip stitch.

Note: It might be a little difficult to find the very first stitch of your rounds. Rotate the shell so that the last stitch is facing north. It will be the shortest stitch (sc) you can see nearest the center of your shell.

Continue to slip stitch loosely into the following stitches one after the next all around the shell. First, you will be slip stitching inside the shell, then at some point, you will be stitching on the contour of the shell (into the regular "v"s on the tops of your stitches. Continue till you reach the very last stitch.

Leave 4" tail, cut your yarn and fasten off.

Weave in your ends neatly on the back of your shell.

And that's all there is to it!

Now you can make several of these seashells to use as decorations or to add to your projects. What will you be using them for?

Thanks for stopping by and let me know if you have any questions in the comments section below.

Happy hooking!

May

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