The Sims 2: SeasonsEdit
Love works very much like the social need does for a regular Sim, and can be raised in the same ways.
Water is similar to hunger as experienced by non-PlantSims. A PlantSim deprived of water will wilt, and eventually die. The water need also has elements of hygiene as experienced by non-PlantSims. Sims will react to a PlantSim toddler with low water as they do to a normal Sim toddler with low hygiene. If FreeTime is installed, hunting bugs will affect a PlantSim's water need as it does a normal Sim's hygiene. To raise a PlantSim's water need, have them drink water from a sink, take a bath or shower, or do anything else that involves having contact with water. This includes having babies vomit on them. Drinking juice will also satisfy a PlantSim's water need.
The sunlight need is similar to the energy need of non-PlantSims, in that energy depletion affects PlantSims much as energy depletion affects non-PlantSims. However, maintaining or raising the sunlight need can be done by exposing the PlantSim to sunlight, either by taking them outside, putting them near a window, or putting them in a room with a greenhouse roof. At night, the Toasty Garden Lamp sans Toast can be used to restore the motive. The sunlight need is also somewhat similar to the Power need of Servos, though PlantSims do not have to become inactive to replenish it. The "maxmotives" cheat does not replenish this motive.
PlantSims have invisible motives as well: comfort and fun. If these motives are depleted, the PlantSim's mood could be in the red even when sunlight, water and love are completely full.
A PlantSim's Love and Water motives are affected by being in the room with a Snapdragon Bouquet.
The Sims 3: University LifeEdit
In The Sims 3: University Life, the Hunger and Bladder motives are covered by leaves, as PlantSims do not have these motives. The Hygiene motive is replaced by a Water motive, which can be filled by having the PlantSim come into contact with water (such as by swimming, using a hot tub, or taking a shower). PlantSims receive a Dehydrated Moodlet if this needs is low and a Hydrated moodlet if it is high.
While a PlantSim's Energy need can be satisfied by sleeping in beds, PlantSims can also "photosynthesize" to restore their energy. Unlike The Sims 2: Seasons, in which PlantSims can absorb sunlight while doing other things, this involves a PlantSim burrowing into the ground and becoming a plant. It can only be done outdoors during the day, and will also replenish the Water motive.