How much space?
Growing ginger doesn’t take up much room at all. Every rhizome you plant will first only grow a few leaves, in the one spot. Over time it will become a dense clump and very slowly get bigger, but only if it isn’t harvested.
The rhizomes underground also don’t seem to mind if they become a bit crowded.
Ginger grows to about two or three feet in height.
A 14 inch pot easily holds three average rhizomes; a rectangular Styrofoam box holds about nine to a dozen. If planting them in the ground plant them about six to eight inches apart.
How much water?
Ginger needs a lot of moisture while actively growing. The soil should never dry out. Don’t overwater though, because the water that drains away will take nutrients with it.
Ginger loves humidity: If you have problems with dry air then regular spraying and misting might help. Dry air can cause problems with spider mites. But that’s not a problem for people who try to grow ginger out of its range and indoors. A sheltered, moist spot in a warm climate will provide enough humidity. Towards the end of summer, as the weather starts cooling down, your ginger will start to die back. Reduce the water, even let the ground dry out. This encourages the ginger to form rhizomes. Once all the leaves have died down your ginger is ready for harvest.
How much and which plant food?
If you are growing ginger in good, rich soil it shouldn’t need anything extra. I grow mine in tubs. I put in fresh compost mix every year and never add any extra fertilizer. If you don’t have good soil, or if you are growing ginger in some standard bought potting mix, then you have to feed it regularly. You will also have to feed it if you are growing ginger in an area that gets torrential summer rains (many tropical regions do). Such rains leach all the goodness from the soil. Work in some organic slow release fertilizer at planting time. After that you can use some liquid fertilizer like seaweed extract or fish fertilizer every few weeks.
When to harvest ginger root?
If you are growing ginger root in the garden you can start stealing little bits of it once it is about four months old. Just dig carefully at the side of a clump. (This “green ginger” does have a lot less flavor than the mature stuff, though.)
The best time to harvest ginger is any time after the leaves have died down. Usually it takes eight to ten months to get to that point.