The ground at my place has frozen more than 7 feet deep this year which is 3 feet deeper than normal. It's going to get even worse over the next couple of weeks. Anyone else experiencing this as well?
I have irrigation plastic pipes installed at the 5 foot depth. I partially drained them last fall with compressed air and opened up everything but I suspect I didn't get all the water out.

Since I have a greenhouse, I would need to turn the system on in late March, well before the ground thaws at that depth. The water source is the city and it comes in at about 5 degrees C. What would you suggest I do? Let it run at low pressure to slowly thaw the ice out? That's assuming I actually have ice in the pipes.