I used to be a daily poppy pod tea drinker for 3 years when they were cheap & abundant online. Worst withdrawals of any opioid I've ever been dependent on because it lasts forever, though the subjective high is not that euphoric compared to pills.
I've tried growing them numerous times & just don't have the knack for it whatsoever. Certain strains are said to have more morphine while others have more thebaine (the nasty stuff), so you'll want to avoid the latter. Purple Tazmanians are possibly the best strain in terms of morphine content (30% morphine-to-other-alkaloid ratio). Burma White, Afghani and Hens & Chicks are also popular for this purpose. If grown in the right conditions, all will produce opium.
Here's an interesting paper where some different strains in various countries were analyzed for morphine content.