A mixture of peat, silica sand and vermiculite is what most people use for them. I'd go 1:1.5 peat pumice, but use whatever you want. Between 2 and 12 weeks of cold stratification is recommended, the latter preferred. The longer you put them in, the more seeds sprout. At two weeks, you get about 10% to grow. At 12 weeks, 95%+ grows. If you choose to sow the seeds outside you simply need to place them in the plant pot and place it outside in early fall. The seeds need cold temperatures to germinate... 15-40 F is the best for them. Keep the soil very damp (not wet) at all times and don't allow it to dry. Make sure no fungus or mold appears! They require little, if any, humidity to germinate and can be grown in a greenhouse if stratified first. Like all pings, these seeds need bright light to germinate. Due to the fact they need to be sewn and kept in cold temperatures, you can grow them outside. I am making this sound harder then it is. With this, your pings should grow in four to twelve weeks (typically around 10 weeks). Once adults, this things grow like crazy! Nearly impossible to kill once you get them to germinate.