Garrisons in SRCW can be controlled manually and locked from the minister but it is also possible to set values that will cause the minister to either increase or decrease the garrisons in an area. With a combination of settings and priorities it is possible to go from no garrisons to full garrisons or the inverse. Note that adding garrison may take the minister some time based on other circumstances.
When sent to High and Defensive, the minister will try for many garrisons. When sent to None and Balanced, the minister will try for no garrisons in the hex