Cannabinol, or CBN, is the cannabinoid within cannabis that is responsible for the sedative effects. If you are interested in a product to help induce sleep, I suggest a strain that is high in CBN. A nice resource to discuss your treatment goals would be the pharmacist at the dispensary. I also suggest working with a dispensary that lab tests their products.
Hope you find my recommendations helpful.
You may also want to read more about cannabinol, or CBN, in our article covering the non-psychoactive cannabinoid (see link below). According to Steep Hill Labs, having 2.5 to 5 mg of CBN will have a level of sedative effects equal to a mild pharmaceutical sedative like Diazepam. You may want to check out Kikoko’s Tranquili-tea, which contains 5 mg of CBN/3 mg THC: https://www.hellomd.com/products/58dc2cfe53635624bf2a4992/tranquili-tea. Though if you’re terribly sensitive to THC even at this fairly low dose, then finding a pure CBN product may be better for you. Hope this helps!
As jennernp and lyp have mentioned, CBN is largely responsible for the sedative effects of cannabis. Accordingly, indica strains tend to have higher concentrations of CBN than both sativa and hybrid strains – which is why indica strains have more sedative properties.
Another way to increase CBN concentration, and therefore sedative effects, would be to age the cannabis. CBN is a metabolite of THC. Thusly, as cannabis ages, more THC is metabolized to CBN.
Here are some strains which are excellent sleep aids: Querkle, Granddaddy Purple, Skywalker, God’s Gift, Afghan Kush and Northern Lights.
However, those strains will all get you high if enough were used. It is unlikely that strains with lower THC will be very useful for sleep. This is because, as previously mentioned, CBN is a metabolite of THC. As such, I would recommend that you age any one of the mentioned strains, which would lower the THC concentration while increasing the CBN concentration. Use as little as possible so that you don’t get "stoned."