heat oven to 400 degrees Fahrenheit
peel turnips if needed/preferred
cut off the root and stem ends of the radishes and turnips
dice radishes and turnips into approximately 1/2" - 1" pieces (cooking time will vary depending on size)
toss with 1 tbsp oil
spread out on baking sheet
roast in oven for 20-30 minutes, flipping every 10 minutes
sprinkle salt over cooked vegetables
cut green onion thinly and sprinkle on cooked vegetables