Linen thread is of course the best thing in the world to make your indigo vat feel useful and it's life meaningful. Linen woven by hand it is sublime. (Right Jean?)
Hand-spun cotton will also make your indigo vat glow with importance and self-satisfaction.
The indigo vats more or less need cloth as well. Their existence is almost meaningless without it.
The best cloth would be something hand-woven.
(This could be repeated one hundred thousand times by every indigo-dyer and indigo consumer on the planet.)
Good cloth to indigo dye is not easy to find. It is out there but often enough, the selection is limited and you settle for less than satisfaction and a few dips later you're not so choosy.
There is a textile area with eighty-five shops or so in Tokyo. It is on the Yamanote Circle line. (Green one.) The station is called, Nippori. (Not 'Nishi Nippori' which means 'West Nippori'.) Avoid this place on weekends and during sales because it can be crowded. There are designers from Japan and all over the world buying textiles on these few streets. There is a lot of 'Made in Japan' textiles so you can expect the highest quality. Like the monstrous textile markets in Bangkok, Delhi and Morocco it can be overwhelming. Where did all this stuff come from and where is it going? There are mountains of polyester fabric which essence is shouting, 'throw me away' before it is even made into something.
Unless you read Japanese this map of the area won't be of much use. It just gives you an idea of how the 85 shops are located in the general area. Nippori station is at the bottom of the map.
Students here at the house are always looking for material to dye in the indigo. I suggest they go to Nippori and at times drag them along on my trips in. There are several large stores called, 'Tomato' that have a strong presence in the area. They have good stuff.
Yesterday, I took the luxury of walking around for a few hours and exploring the smaller stores and the upper floors of the big stores. (Usually in a mad rush to get out of the area, I swoop in, shop and run.)
The retro-Japanesque stuff makes good presents to take back to your home countries.
It is also a reasonable place to go shopping for cloth if you are coming out to the farmhouse and staying in Tokyo beforehand. Remember all cloth has to be boiled to have the sizing removed and this takes time and energy.
All this written....back home, exhausted from a long day in Tokyo I finished the fringes on these blankets woven last year. The wool is amazing. It is from Nancy Zeller at Longridge Farm. http://longridgefarm.com The wool was first dyed with gardenia pods to get a clear yellow and then a few dips in the indigo to get the green. Peddling around on the twill and using Nancy's silk/wool blend yarn for the weft on the lighter blanket.
Thinking....this is what I should be making and teaching. Stop all this Nippori bought stuff nonsense and focus on making thread/yarn from materials at hand and weave them. Hand-made is important. Very very important. Having been a marketing student in the 80s when marketing, targeting youth was about to take off, watching this documentary made me nauseous. It is worth a watch. If you do make things by hand it will definitely make you feel better about yourself as you despair on the future of humanity.
Make You Feel Good About Making Things.