Ginger plant leaves are turning brown and the stem dies.
Since you don't mention what kind of ginger you have ( variegated or shell ginger - Alpinia species; torch ginger - Etlingera elatior; edible ginger - Zingibar officinale) , or if it's in the ground or container, indoors or out, I can't be very specific, but leaves turning brown and stems dying makes me think first of too much moisture in the soil, and after that fungus (related to the previous moisture problem,) or insects. You might want to take some soil and plant samples to the Extension Service for analysis. This site will help you find one: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm
We have approx. 5 varieties of ginger plants in our community garden which is on the Gold Coast Queensland, Australia. Can you please provide pruning instructions or guide me to where I can acquire some?
Here are some good ginger pruning instructions: http://www.hoeandshovel.com/2013/04/how-to-trim-shell-gingers.html
Does one cut it off at ground level or further up the stalk?
If you're talking about pruning after flowering is done and the plant is starting to die back, you would want to prune at ground level. I think. There's really not very much information on this plant, but based on the plant's appearance, that's what I would do if I had one. You might cut one of the stems in the middle, just to make sure it doesn't grow from such a cut. Did you know that if you don't cut off the flower and allow the inflorescence to bend over when the flowering is done, it will start a new clump of plants from where the inflorescence touches the ground?
What is the best way to root ginger bought at the grocery store?
This article will help you: https://www.gardeningknowhow.com/edible/herbs/ginger/growing-ginger.htm
I have planted one acre in ginger and they are one month away from harvesting but the problem is that they have been overgrown by a lot of weeds, grass, brush, etc. What I would like to find out is if I leave it to die or cut down everything would the ginger plants grow back and would the harvest be larger? Would it make sense to start over in this way? Or should I harvest it and use some to replant?
If you are only a month from harvest, I would check a few plants and see how the rhizomes look. If they look full and healthy and ready to harvest, I think you should go ahead with the harvest and replant some for the next round.
Do ginger plants grow back from the roots after a freeze? The ginger plant is brown all over.
Ginger is not cold hardy. Rated to grow in zones 9 thru 12.
If you plant experienced freezing temperatures, it's most likely did not survive.
Here is a link about growing ginger.
https://www.gardeningknowhow.com/edible/herbs/ginger/growing-ginger.htm
Can one grow this plant in Toronto, Canada? And what zone do I live in please?
You could grow this during the summer and attempt to winter over indoor in a heated greenhouse or sunroom.
Your area is zone 6a through 7.
Here is a link about Beehive Ginger.
https://www.gardeningknowhow.com/ornamental/flowers/ornamental-ginger/growing-beehive-ginger.htm
http://www.plantmaps.com/interactive-ontario-plant-zone-hardiness-map.php