You Asked, Kathy Answered: Overwintering An Indigo Vat

We get lots of emails from customers about challenges with dyeing and needing Botanical Colors’ President Kathy Hattori’s help. Why not share the learning so we can all benefit? From our inboxes to you, it’s simple: You Asked, Kathy Answered. Email questions@botanicalcolors.com with your plea for help!

YOU ASKED: I’ve moved to a new place and don’t have room to bring my buckets of indigo indoors for the winter (Seattle area). I’m pretty sure that I will need to re-start any ferment in the spring, but will my indigo vat survive otherwise? Somewhat of a beginner here.

KATHY ANSWERED: Survivability of overwintering an indigo vat depends on a number of factors. If you have a true fermentation vat then it may or may not survive the winter outside as the cold temperatures may cause problems with the bacteria in the vat. Many fermentation vats require warm temperatures to survive and regular care and feeding.

If you have a 1-2-3 type vat, it may do just fine as it is not a fermentation vat, but expect that it may take some effort to bring it back into balance. What I usually do with a 1-2-3 vat that I’m trying to revive is to warm it with a bucket heater to approx. 90F, remove the heater and stir it well and let it settle. I’ll stir the vat a couple of times over the next hour or so, and I’m looking to see if the vat produces an indigo flower (the cluster of bubbles that floats on the surface of the vat), and if a “skin” or metallic sheen is visible on the surface of the vat. If I start seeing that activity, then I’ll add a small amount of calcium hydroxide and fructose (usually 1-2 Tablespoons for a 5-gallon vat), stir and see if the indigo flower gets more vigorous looking, the bubbles are darker, a metallic skin forms, or other activity. If I see all of those signs, I will try dipping a small piece of test fabric and evaluate the depth of shade I’m trying to get. If the vat still seems very light, it is possible to add more indigo, calcium hydroxide and fructose to the existing vat to enrich it and once the new enrichment is incorporated, stir well, let settle, observe for reduction and start dipping.

You might also want to read:

A Deep Dive into the 1-2-3 Indigo Vat

Hints & Tips for Natural Dyers: How to Minimize Indigo Crocking

You Asked, Kathy Answered: Let’s Talk Indigo

Shop all things indigo:

The Easy 1-2-3 Fructose Indigo Kit (comes with dyeables!)

Japanese Indigo Folding Fan (Sensu) by Takayuki Ishii

Organic Indigo Ink – 3 Varieties

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