In order to properly grow grapefruit, you need to provide relatively warm conditions both day and night. This means growing them in temperate or tropical-like regions in full sun — preferably in USDA plant hardiness zones 9 and up, though some success can be achieved in zones 7 and 8 with suitable care. Grapefruit trees also prefer well-draining, loamy soil.

Read more at Gardening Know How: Grapefruit Tree Care – Tips For How To Grow Grapefruit https://www.gardeningknowhow.com/edible/fruits/grapefruit/growing-grapefruit.htm

Hi , My name is Jerome ,The tree today is potted in a very large pot . Maybee 20 gallons, the tree itself is very healthy and stands almost 9 ft high including the pot . I have removed thorns along the trunk so my kids do not injure themselves The plant is watered regularly and I have been mixing in All Purpose plant/food fertilizer ( 20-20-20 ) in with the reg waterings . As well the plant sits in front of a window that is in sun from 10 am until 6pm .