“The good thing about it is it doesn't need to be watered that often.”
You bought your girlfriend a potted cactus for her office. You're explaining why you thought it was a good idea for a gift.
The good thing about it is it doesn't need to be watered that often.
Use this expression when you want to talk about the good points of something:
The good thing about my job is that I get a lot of vacation time.
The good thing about living in a big city is that you can get everything you need within walking distance.
In grammatically correct, formal English, you should include "that" at the beginning of the clause:
The good thing about it is that it doesn't need to be watered that often.
In conversational spoken English, people often leave "that" out.
Use "___ needs to be ___" to talk about work that someone needs to do:
It needs to be done soon.
English speakers use "be __" to avoid saying exactly who should do something. For example, you might say this this to an employee:
The files in this folder all need to be reviewed.
Instead of this:
You need to review the files in this folder.
The first one sounds softer and less direct.
Or you can say "___ needs to be ___" if you don't know who should be responsible:
That old building needs to be knocked down.
Use "___ doesn't need to be ___" when it's OK not to do something:
No, they don't need to be cooked. You can eat them just like that.
When you give a plant water, it's called "watering" the plant.
Can you water the plants for me while I'm away?
You can also "water" a garden or lawn:
The best time to water your lawn is in the early morning.