The problem with Mars is that it's surface is not very rich in minerals important to plants.
There is also a significant lack of water on Mars.
Does this mean that the only viable solution to plant growth on Mars will be to melt the ice, mix with minerals brought over from Earth and then directly distributed to the plants through hydroponics?
This itself has the issue of requiring the minerals to be brought in externally, and isn't very sustainable in the long run.
Is there a more sustainable method that could be investigated to allow initial plant growth for a sustainable colony on Mars?