I grow both of them and a few other edible gingers in zone 7b (Raleigh NC). 2 by 2 is not much space. Neither of these plants gets very big above ground but you want lots of space under ground for the roots to spread out. I plant one root cluster every 2 feet in my garden. Turmeric can handle any amount of sun (as long as its watered) but root ginger does better in the shade for me. It takes about 265 days to get optimum flavor in the roots, so I plant the roots in March (indoors for my zone) and get them to sprout and then raise them as houseplants until the daytime highs are mostly in the 80's, then plant them in the garden. I harvest whenever the night time lows are predicted to get around freezing but anytime after Halloween will work. I can get most store bought roots to sprout but Turmeric can be tricky. I have had Turmeric roots take more than year before sprouting but most of the time they sprout in about a month. You can just lay them on top of the soil and watch for green tips to form, or plant them underground. If your yard never freezes you may be able to harvest root ginger throughout the year by just breaking off bits of root and leaving the plant in the ground. Root ginger grows right at the surface (Turmeric is underground).

True and second year crops are primarily used for cattle feed. Pithy, bitter, and lower nutrient levels. Or tilled in as a green manure for soil improvement. Not something that is normally done intentionally for human food crop. Dave

It depends on how you want to use it for pickles - weed, seed, or heads. Different recipes call for different forms. We harvest and dry quite a bit as dill weed (leaves). Probably 1/2 of it that way as we use dried dill weed for much more than just pickles. If you don't want to dry it then you can freeze it in ice cubes but that dilutes the flavor IMO. We let some go to form seed heads to harvest the seed, and harvest some of the heads before they go to seed and vacuum seal them for the freezer to use as heads later on in pickles. Dave

I have several curcuma and globba gingers in pots due to armadillas digging stuff up. They like to eat my ginger bulbs. Anyhow, rihjt before our first freeze, I let the pots totally dry out and when the foliage dries up I clip it off and put the pots in a shed over the winter. It stays above freezing in the shed although Curcuma and Globbas can take some freezing temps. In late April, I take the pots out of the shed and set them in semi shade and water them. Pretty soon they start leafing out. You must just water them a little until they leaf out. You dont want the pots soggy or they will rot. Been doing it this way for about 5 years now :)