I live at 9000' in southern Colorado...what strains ire better for high altitude growing?

A customer has a question and I hope we can get some opinions on it, thanks

“I bought five white widow seeds earlier this year and planted two of them on may 20th. Only one came up so I planted the other three two weeks later. Only one of them came up and it died yesterday. The one that came up from the first two I planted is still alive but is only about one inch tall and only has it’s first set of real leaves. After this much time it should be a lot bigger. I planted some ak47 seeds in march and they are doing fine, one is a little stunted. My question about the strains is which are better for high altitude growing? I do live at 9000’ in southern Colorado, does anyone has any recommendations for this altitude? I like sativa strains. Thanks for your help.”

Maybe super silver haze more overall, how are they germinated? What is your medium? What is your ph? Temperature and humidity?

This stuff will help us help you also are you trying to plant in pots or the ground