@PenguinFoop
1. No, they don't really need houses. In ts2 I sometimes built a treehouse where I had some plantsims and bigfoots living together, but it was really only for bigfoot's sake the house was needed.
2. No they won't die. They do pass out though, and lack of water will make them wilt. A passed out wilted plantsim can be watered by another sim with a watering can!
3. In ts2 they don't need to sleep, though it's good to have atleast a tiny greenhouse with a sun lamp, to keep them in good mood during the night.
In ts3 they do need to sleep and can do so in a regular bed or by photosynthesis.
4. They could only do this in ts3. They would dig themselves into the ground to photosynthesize.
5. All the other things that any other sim would do for fun. They did have some unique abilities though. In ts2 they could play pranks on other sims by blowing pollen on them. In ts3 they had special kisses.
6. Of course they could only get sunlight during the day and they didn't get less on cloudy winter days compared to sunny summer days.
And as I said before, during the night, they had the sun lamps in ts2 and they slept in bed/photosynthesized in ts3.
7. Yes, like any other sim they too could pick and sell crops! XD
In ts2 there's a juice blender where you can put veggies and fruits (and even boots that you can get from fishing). A plantsim's water need will be filled by drinking it!
They are also better at gardening than other sims and can talk to plants.
8. In ts2 that would be the only way to get water unless you had a pool, shower or lived on a beach lot.
In ts3 there's the photosynthesis and also swimmable lakes.