Possible stuck fermentation?

For my first batch, I used a 1.8kg can of John Bull India Pale Ale LME and a 1.6kg can of light LME (7.5lbs total LME) to make a 5 gal. batch. After adding cold water, I let the wort cool to 72 F, and measured the OG at 1.052. I sprinkled an 11g package of Windsor brewing yeast on top and closed the lid on my fermenting bucket. That was Tuesday morning. About 10 hours later, the first bubbles started coming out of the airlock. By Wednesday morning, it's bubbling pretty good.

Then Wednesday evening, I did something stupid. I thought It would be better to move it to the basement where I thought the temp was about 65F. I check on it the next afternoon, and the temp is actually 60F, and all airlock activity had stopped completely. I brought it back upstairs, let it warm up, and rocked/swirled the bucket a bit to try to suspend the yeast again. The specific gravity at this point was 1.020 (Thursday evening). The airlock started bubbling a little, so I thought I would be ok. But I just took another gravity reading (Monday evening), and it's still 1.020, maybe 1.019. I really don't think it's done fermenting. Should I add more yeast?

Thanks in advance!

It has only been 6 days right? If so, just let it sit and take another reading in another few days. I made the mistake of racking to the secondary too soon, don't make the same mistake I did.

What is the FG you're targeting?

It does sound like you're stuck, but patients is definitely necessary. I'd let it go for several more days before taking any action besides an occasional good swirling.

I've posted before that I had a stuck fermentation, and to remedy I was advised to throw in some yeast re-energizer (available at LHBS's), and to re-aerate. The yeast re-energizer cant hurt anything as it is sold to fix stuck fermentations specifically, but re-aerating is definitely risky (I got beat up a little for forwarding this advise). Talk to somebody who really knows what they are doing before aerating if you decide to go this route. These methods worked for me, and the beer turned out great. I was past two weeks in the primary before I took any action, and I was stuck at around 1.030.

I would also recommend waiting - possibly as much as 3-5 days, then take another gravity reading. If it still hasn't changed, pitch more yeast if you have it.