Home-grown Weld

Funny story. So I’m growing weld for the first time, which is a dye plant that gives the most light fast yellow known. It shot up stalks and was taller than me, the little yellow flowers were starting to open. I wondered when the heck I should pick it, so I did what anyone with a computer does – I Googled it. And I became a bit confused by all of the hits for marijuana cultivation on the first page of results. (Get it? Hits? Ba-dump-chhhh!) At which point I notice the one-liner below the search box:

Showing results for when to harvest weed. Search instead for when to harvest weld.

Um, yes, please search instead…..

Anyway, opinions seemed to vary on when to harvest weld (imagine that), and I also heard from another dyer that plants in crappy soil that only grew to about 2 feet tall yielded the best dye, and larger plants were likely to be quite weak. Hmmm. My plants were a bit over 2 feet tall….these are the couple I left after harvesting 4 more just like them:

I cut off the flowers, put them in a paper bag, and hung the stalks upside-down in a dark place to dry. I left them for about 2 weeks. The flowers were already separated, I further separated the leaves, the remaining small stalks, and the large main stalks. Time for a test! Here’s the relevant data:

  • Yarn was superwash merino
  • Mordant was alum
  • Weld used at 50% WOG

For those not familiar with natural dyeing terms, WOG is “Weight Of Goods”. In other words, the amount of weld used was 50% the weight of the yarn dyed, or 50g of weld per 100g of yarn. My 5 batches were:

  • European dried weld, what I normally purchase and use


  • Home-grown weld large stalks (not pictured)
  • Home-grown weld small stalks


  • Home-grown weld leaves


  • Home-grown weld flowers


And the extraction & dyeing process I used:

  • Soak weld in water overnight
  • Soak test skeins in water overnight
  • Put weld and water in a stainless steel pot, bring to boil
  • Boil for 30 mins
  • Strain out weld
  • Add wet test skein to hot dyebath, leave to dye/cool overnight

Normally I’d be more conservative about adding cold yarn to hot water – with minimally processed wools, it’s a recipe for harshness, if not outright felting. But these were small test skeins, superwash wool, and I didn’t want to spend a lot of effort on cooling the dyebath, since I was also dyeing production batches at the time. So I didn’t really care if they lost a little hand.

And the results!

IMG_6606 (Large)

IMG_6601 (Large)

Going from most saturated (left) to least saturated (right) in both shots above:

  • Home-grown flowers
  • Home-grown small stalks
  • European dried weld
  • Home-grown leaves
  • Home-grown large stalks

So…I have to say I’m pretty stoked. I got what I’d consider really good color from my first crop! The flowers and small stems were definitely worthwhile, and the leaves were about on par with the European dried weld I had. The large stalks aren’t really worth the effort, I’d say they have about equivalent color to a typical exhaust bath.

As far as when they were harvested…well, they had been flowering for the better part of a month, and the flowers near the tops of each head were just opening. Plants were about 5 feet tall, and as you can see in the very first pic, had one main stalk with many sub-stalks and flower heads. Another very interesting thing is that all of these plants are less than a year old. This is a little strange – weld is supposed to only form basal rosettes the first year, like so:

Weld rosettes (Large)

I planted these in July of last year, so I guess you could argue that it’s the second growing season and they’ve seen one “winter”. But, I planted more seeds in early April of this year, and a few of them are now stalking in their first season:

Weld small stalk (Large)

San Luis Obispo does go hot/cold a lot in the spring and fall. It’s not unusual to have a week of 85-90 degree weather followed by a week of 60 degree weather. So I think the temperature swings faked them out into thinking they had seen a “winter”. Speaking of “winter” – it does dip below freezing at night, but a high in the 50s would be a pretty cold day. I shut off the sprinklers between November and February this past year, and the weld rosettes were overgrown by coreopsis and marigolds. So I pretty well neglected them for about 4 months and they survived and dyed splendidly.

The moral to this story – JUST GROW IT! Seriously, you have nothing to lose and weld is spendy stuff, so there’s a lot to gain. As you can see from these last 2 pictures, I’m planting it in whatever space I can around the house and it seems to be doing well.

Where you can buy weld seeds:
Thyme Garden Herbs
Sand Mountain Herbs
Alchemy Works
Earth Arts (link removed, site not active)
The Woolery
Horizon Herbs doesn’t carry weld, but carries a lot of other seeds and even madder seedlings in season.

Do note that the proper name for weld is Reseda Luteola. The main dye compound is luteolin, which is the most light fast natural yellow. There is also a species of plant called Reseda Lutea, but this is not true weld and contains zero to very small quantities of luteolin (Cardon, Natural Dyes, pg 171). So make sure you get the right stuff!

Happy growing!

edited 07/10/2014 to update links


About alpenglowyarn

Engineer, maker of tools for yarn dyers and maker of other interesting things. I still do some natural dyeing, but not as a business. View all posts by alpenglowyarn

6 responses to “Home-grown Weld

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