Quality of Feverfew

I've become very interested in growing my own herbal remedies, especially given the fact that Feverfew has proven nothing short of a miracle for my migraine symptoms. (I've been taking Feverfew since 01/2004, which has resulted in almost complete cessation of my migraine symptoms – before taking the herb, I was unable to get up from my bed for days or weeks at a time).
Nevertheless, one concern has risen about the quality of the Feverfew I've been purchasing in capsule form to date. The label on the bottle of the freeze-dried Feverfew product states that both the stem and the flowers are included in the process. For this reason, I'm very interested in learning how to grow and freeze-dry my own Feverfew. I also noticed that the percentage of Parthenolide ranges between 0.1 and 0.2%. I'm interested in knowing where I can purchase Feverfew seeds that yield a minimum of 0.2% Parthenolide (I believe Canada was working on standardizing a minimum, correct?)
Are there any sources that are known for providing consistent, high quality seeds and related products from which I can make an informed purchase? I'm also interested in equipment, given that I live in Connecticut and would have to grow the plant year-round.

Well, we would like to think that we sell the kind of seeds you are looking for. That's one of the things we are know for: having superior varieties with elevated active constituents.
While it is true that Canada has developed a 0.2% parthenolide standard for feverfew products, it is not at all clear that this constituent has anything to do with the herb's medicinal action. At one time it was thought that parthenolide is responsible for the anti-migraine effect but later evidence did not bear this out. Parthenolide then began to be taken to be a "marker" compound, a compound whose presence indicates the identity of authentic feverfew herb.
In my opinion parthenolides are not suitable marker compounds because they are unstable and will degrade easily in normal processing and storage. In order to meet minimum parthenolide standards, herb companies often concentrate feverfew leaf in extract form. So while the feverfew product meets the 0.2% standard, the actual anti-migraine ingredient may be concentrated also, and may thus vary considerably from batch to batch of products. This defeats the whole purpose of a marker compound standard in the first place.

Is there a way I can measure the actual content of Parthenolide in Feverfew, or would that involve instruments I may not have access to?

You need High Performance Liquid Chromatography (HPLC) equipment. This equipment is expensive to acquire and run, and requires extensive training to operate effectively.

I will greatly appreciate any information you can provide to a genuine novice like me.