Everyone asks "how do you find time to do this?" Having a three-year-old and a ten-month-old, full time job, farm and a husband can keep me busy, but making my yarn fits right in to our busy life! I can cook my yarn on the stove, right alongside dinner! That's how this started. I'd put some yarn in the pot, mix in my dyestuff and let it sit.
As I've started experimenting more, I've found there are a few methods that work to get a low heat exposed to the dye and the yarn for a long period of time. I have a few pots I keep just for dying. I'll start by getting my dyestuff heated up in a liquid. Let's take Marigolds for instance. Marigolds are lovely and my plants have been super prolific this year. Sometimes I throw the whole flower head in and sometimes I snip off the petals and use those only. I put them in water and slowly heat them at about "low-medium" or "2" for a few hours, until the pot is steaming or small bubbles start to form and move to the top.
I make sure to mix every so often to keep everything submerged. Once it's heated, I'll turn it off and cover it. 24 hours later, I take out the 'stuff'. I've skipped this part and just put in the yarn and I seriously advise against it unless it's a big 'stuff'. I've had to scrape blackberry and chopped up rose petals off of yarn and it's not fun.
I'm left with just liquid dye and I'll put in my pre-mordanted yarn. Make sure it's soaked all the way through and mix it around so the dye gets into the skein really well. Some variation of color is good but if you only dye the outside of a skein, that'll look funny!
I heat everything up again, careful not to shock the yarn with a sudden temperature change. Again I wait for the steam or bubbles but I keep it on a low temperature so it can sit for a long time. Once it's good and hot I take it off the heat and let it sit for another 24 hours.
The best way to tell if your yarn is done is if the liquid around it is clear. That means your yarn has taken up all of the color. If it hasn't but you've reached a color you like, you can use the liquid again to get a lighter shade. (this is a good way to do a fade, too)
After your yarn has sat in the dye for as long as you want, give it a rinse. Rinse until it runs clear and hang it up to dry. I love hanging mine in the tree on a warm summer day but those are numbered around here I'm afraid!