Hi! I'm Gina, an organic fibre and dye farmer - Welcome to my blog!

I'm excited to share my journey of growing Japanese indigo (Persicaria tinctoria) over the 2023/24 season in Lincoln, Canterbury. Whether you're a seasoned gardener or just starting out, cultivating this beautiful dye plant at home can be a rewarding experience.

In this post, I'll walk you through each step of the process—from sowing seeds and transplanting, to nurturing your plants and harvesting your abundant foliage. I'll also share tips and insights from my personal experience, based on both organic farming principles and the comprehensive Fibershed indigo report.

If you're looking for Japanese indigo seed, you may still be able to find some at my shop here.

Now, let's dive in and discover how you can grow Japanese indigo in your own backyard!

Sowing seed

One thing to note before we get started is that this plant is very forgiving! If something in my tips doesn't work for you, feel free to adapt to suit your needs and resources available and go with that. You'll find that the plants will simply follow your lead!

Japanese indigo does well if started indoors and transplanted outside after any threat of frost has passed. In Christchurch, this can be as late as November!

For small amounts, sow seeds in trays with damp seed raising mix, or if sowing larger amounts, prepare soil in a greenhouse to a fine sandy tilth and sow into damp soil. Ensure your trays, pots or seed beds are free draining so the seeds and roots don't get waterlogged.

There is no need to plant single seeds if you don't have the time or space, you can freely scatter the seeds in broad trays of mix, lightly cover with soil or river sand and separate them when it comes time for transplanting. The seedlings are quite robust!

Keep the soil warm and moist, checking below the surface of the soil before watering as the top can dry out faster than the soil below. Keep ontop of any weeds that may show up.

Seeds will germinate in around 4-6 days, showing their round cotyledons (first leaves) and burgundy stems. The first true leaves are crinkly and will develop by around 2 weeks.

Transplanting

Only transplant outdoors once the risk of frost is gone as frost can damage the plant considerably. Planting into a sunny spot will help with good plant development as well as helping to eliminate pest and disease vulnerability.

Prepare your field, gardenbed or containers with compost well ahead of time so that the compost has time to settle into the soil. As we are growing this crop for its green leafy foliage, the soil should be well stocked with nitrogen to boost vegetative growth.

Once the seedlings are about one hand tall (horse measuremet term there!) or about 20cm tall, they are ready for transplant. However, as mentioned, if you aren't ready to transplant just yet, that's ok! They will happilly relocate whenever it suits you.

To loosen your seedlings from the nursery bed, plunge a garden fork next to your section of plants and lift to losen them at the roots. This allows for easy lifting of the seedlings with less damage should you try with a trowl or spade.

As you'll see in my photo above, the plants are "nodal" which means they grow at each of the leaf intersections. This is just another wonderful benefit of these plants! Why? Because the plants will root and regrow at these points, which means if you lay the plant down and cover the roots and a few extra nodes with soil, being sure to leave the tops above ground, they'll magically multiply and offer a wonderfully bushy plant!

Because I had 5,000 seedlings to plant out, I wanted an overly bushy crop of indigo for easy harvesting, so I planted my seedlings in bunches of 5-6, laying each bunch down and covering a few nodes up the stem. We compressed the soil quite firmly so that the roaming chooks wouldn't undo our hard work!

On a smaller, home garden scale, I'd still plant a few seedlings in bunches together to help the plants establish their bushyness. The nodes buried under the soil will take some time to root and develop shoots, and by this time, you may be ready to harvest your first batch of leaves!

Keep your soil moist throughout the growing season. Once the plants get bushy, their mass will help retain moisture in the soil so that you won't have to irrigate so much.

Harvest

There are many ways to test the leaves for pigment production. Personally, my view is that if the plants have bushy leaves and the stems are taller than 50cm or knee height, they're ready for harvest. However I'll share a few ways to check anyway.

One way is to mash a leaf up in your hand to damage the celulose structures and release the juices. Crush and mash in the palm of your hand with your thumb for a minute or two and wait about 10 minutes for colour to develop.

Another way is to hammer a leaf onto white cotton and watch the colour develop.

Finally, if you have time, you can pluck a leaf and allow it to dry. If it turns blue when dried, then it contains pigment.

When you're ready to harvest your wonderful indigo foliage, simply cut the stems with secateurs, or snap at a node with your hands, leaving at least 20cm of plant above the soil for regrowth. Treated as a cut-and-come-again crop, you should be able to get 2-3 harvests out of your plants.

Continue to harvest your foliage until the plants start putting out flowers. It has been documented that the pigment starts to decline once the plant begins to put its energy into reproduction. I still collected stems that hadn't gone to flower as a last ditch effort to generate colour and it was successful!

Storing and using your indigo

This is a subject for another blog as the options and processes are numerous. However in the meantime, here's a few resources to help scratch your itch:

• Maiwa, How to dye with indigo: https://naturaldyes.ca/how-to-dye-with-indigo 
• Michel Garcia You Tube channel: https://www.youtube.com/@MichelGarcia-jf1zv
• Facebook group "Indigo pigment extraction methods": https://www.facebook.com/groups/indigopigmentextractionmethods/
• You can find the Fibershed report that I reference here: https://fibershed.org/wp-content/uploads/2018/01/indigo-planting-harvesting-nov2017.pdf 

Thank you for taking the time to read my journey! Do let me know if you're growing it yourself and how you're finding it! I'd love to hear your story.

Happy growing!