From seeds to Blue, growing Japanese Indigo in Scotland for dye

My name is Elisabeth Viguie Culshaw I am a natural dyer based in Glasgow and I am in love with the color blue.

This is the first post of my Indigo growing season. For the next six months on a regular basis I will be writing about growing and using Japanese Indigo in Scotland. I will describe my process and give useful tip to those who would like to try their hands at growing their own dye plants.

I usually run this as a paid course but I have decided this year to open my knowledge and tip in a FOC blog post way to allow more want to be growers to catch up. I will be sharing regular photos of the result on my Ig page @bettysbeautifullife make sure to give it a like if you would like to keep up. The posts will naturally stop end of September at the end of the season and the opening of my “Shades of Blue” Indigo exhibition in Glasgow.

I have been working with Indigo for many years. Before the Covid crisis I travelled the world to learn from Masters and plants in the East. But Covid trapped me at home and I decided to start growing my own small crop.

After some research my choice was for Japanese Indigo. I found a grower in Norway and my thinking was that Scottish weather and light level would not be worse. In 2021 I grew my first crop, 600 plants in a new grow box in the middle of my Glasgow Urban garden.

When the world was in chaos with the biggest health crisis of the 21st century I sat in the garden waiting for my plants to grow.

I found that growing Japanese Indigo connected me deeply with the seasons, the color blue became very connected to the plant.

In 2022 I started growing in The Glasgow Botanical garden 1500 plants of Japanese Indigo or Persicaria tinctoria in two ordered bed at the top of the garden. In 2026 I will be growing for the 5th year. In September I share the fresh leaves with the pubic.

In 2026 I will be presenting “Shades of Blue” a month long exhibition about “Indigo” the plants, colors and processes. The Auld Kirk in Kirkintilloch (Scotland) will be hosting me. Together we are growing Japanese Indigo plants in a box just outside the entrance door of the museum. We want to inspire the visitors to look at growing their own dye plants.

Growing Japanese Indigo in Urban Glasgow in 2026

In this ongoing blog I will be sharing my growing journal for 2026. If you are interested about growing you will find here my notes and best advice.

Every week I will post about my development and in the summer I will share some recipes for using the leaves for color.

APRIL – WEEK 1:

April is the beginning of my growing season, in Scotland the late spring means the soil does not warm up for several months after the new year and it is possible to have frost well into March.

As a general rule I germinate my seeds indoors in trays in seedling compost because despite the extra cost I feel I get a much better rate of germination that way. I usually plant around 1500 plants in drops of 5 seeds in small cubicles. In my experience Japanese Indigo plants are very sociable and like to grow in groups. I have experimented with groups of 10 but as they mature in their individual pods they draw too much food from the compost and tend to grow leggy. 5 is my favorite number.

I plant to germinate for several beds. One grow box (1.5 x 2.5 m) in my own garden (part sun/shade, fresh compost with addition of liquid fertiliser during the season), two beds (1.2 x 5.5 m in the grounds of the Glasgow Botanical garden,) the soil is clay rich and while I add compost and manure every year the plants are never as well developed as my own space. This year I am also growing for a 1.2 x 2.5 m box outside The Auld Kird in Kirkintilloch. In total I am germinating 1515 seeds this year.

In April I plant the seeds and they will take around 10 days to germinate. After a few days once the second set of leaves have opened I will transfer them into small pots and start hardening them. Around mid to end of May they will be ready to plant outside and at that time the ground will have warmed up.

In other areas (South of England), Europe or USA the germinating will have been done in March but for me it is essential to keep an eye on the weather. So for me April is a great month.

This week I identified some small trays in the shed, made of plastic I bought those several years ago. I fill them up with soil, pop 5 seeds on top of each cubicle and dust a small layer of compost.

The trays are resting in my growing room. I live in Urban Glasgow and while I have a great garden shed, I dont have a green house. For me growing dye plants has always been a temporary activity and I believe in trying to as much as possible using what I have to make this work. So to that effect I use a room in our flat which has a great very large window with mid day sun and a lot of light. This works like a green house. A large table just behind the window acts as growing table and end of the summer a drying table. The temperature indoors is around 20 degree which is great for this germination to take place.

My green trays are resting on top of a plastic small tray. I can water the seeds quite happily. In good time the grown seeds will be transferred into small compostable pots in group of 5 and those will rest on the same table until they need to harden outside.

This year I have a new tool… a watering bottle made of a recycled bottle. I am always on the look out for a fine watering can for my seeds and I found just the thing. An old plastic bottle that was in my recycle bin happen to be keen to help. I heated a sharp knife on one flame of the cooker and used to pierce very sharp and small holes.

After planting the seeds I covered the whole bed with some plastic sheeting. I know it sounds a little strange to work with plastic on eco techniques but the plastic covering the wet earth will heat up when hit by the lunchtime sun and will create condensation which in turn will keep the soil humid and warmer. This will “fake” a green house effect. It will help the seeds feel they are in a warm climate.

The general temperature of the room is between 16 and 17 degree centigrade and I keep an old thermometer in the corner of the window. But at lunchtime the sun hit the window as this room is south facing and the temperature rises above 25 in the cubicles.

As a general rule I do not believe you need to purchase sophisticated, and expensive tools to perform a task. You have to understand what you are trying to achieve and trouble shoot with what you have around you.. that is the real sustainable way.

When deciding to grow semi large scale (i think 1500 plants is semi large scale) I made the conscious decision not to create a stash of items that would ultimately end up in landfill. Some garden tools had to be purchased but I did not built an expensive greenhouse, I did not buy a lot of compost, and so on.. Year after year I reuse the same green trays to germinate the seeds. I think this is the right way. You may not realise that you have at home many many things you can use for this. Take a look around. There is great satisfaction to make do with fewer items and achieve the growth of plants.

I hope you can join me on my journey of growing plants for blue. If you are in the UK I suggest contacting George at Bailliwick in Guernsey. Find her on instagram under Bailliwick. For now she supplies the best seeds.

On this note, I do not produce my own seeds. The growing season in Scotland is very short and often it freezes in the autumn too early for seeds to mature. I focused on producing seeds in 2023 and the growing from them in 2024 was of poor quality. I came to terms that I would be ok with buying seeds years after years. I feel blessed enough to be able to grow.

On my next post I will share more detail about my set up, some information about soil, fertilizer, way of planting, about my timing and my climate.

Please be aware if you are a beginner that every soil is different and will give a different result. Be patient, be grateful and learn to accept what nature gives you.

Good luck.

Betty xx