Where to get proper soil?

[Beanier]

I'm in karachi and I'm trying to grow tomatoes with horrible luck. The plants never last long enough. And everywhere I look for proper potting soil they give me composte or sand. And neither are ideal for growing. I'm trying to set up a proper greenhouse on my roof and I need someone who knows where to get a hold of someone who knows about soils and mediums and pH that can also provide me with soil. Any idea where I can go?

[Izhar]

The tomato plants can be grown easily in Baalu matti and ojhir ki khaad mix in 3:1 ratio.
Here is a topic on tomato growing tips: viewtopic.php?f=30&t=650