DO NOT OVER WATER GINGER AT ANY STAGE. Sorry had to use my all caps voice on that one. Wet media is asking for trouble. Ginger needs a fair amount of water but is actually very sensitive to standing water and poor drainage. Yes it can tolerate heavy rains if it has drainage but then we worry about washing away valuable fertilizer. I like to saturate a well draining media and then wait until said media has become a little dry...not bone dry mind you.
As ginger grows in size it will extract more moisture from media and soil and you will have to increase the frequency of your irrigation operations.
Overly wet media will encourage disease. This especially true when combined with hot summer temps. As ginger rhizomes are fleshy and tender they are easy prey for any casual pathogens lurking as they like to do when conditions are right for them, wet and hot usually.
As mentioned in the presprouting section, ginger is fairly picky in its early stages when it comes to water. Overwatering during presprouting and early transplanting is the main problem to watch out for - too much water causes the ginger to stop growing, which could really delay your crop time.
Important watering tips
• Water your seed as soon as the soil or media feels dry to the touch. If it is dusty or starts to separate from the edge of the container, it is too dry. When watering, make sure the media is saturated, but not muddy.
• If you are growing in an arid climate, it’s a good idea to mist the leaves to raise humidity.
If, on the other hand, you are growing in a climate with heavy rain, cover the plants with plastic to keep them from being overwatered. This is vital if you are growing in an open field, or if you just transplanted your ginger.
• If it is late in the season (late July-August), and the temperature is hot, don’t water too frequently. It is more vital to feed the soil, and in most cases it’s good to water the seed about every 2 days.
•If you see the foliage start to curl slightly in the early afternoon, it means the ginger needs water immediately. However, this method should be used as a last resort for checking whether the seed needs water, so if possible, try not to get it to that point.
•If you have a bag or hoop house culture, then a drip system with a timer would be beneficial for you.