Field Guide

Every region, every number.

PlantFriend is a quiet game and you can absolutely just play it. But if you want to know what is actually happening to your plant when you drag it through a sunbeam or stand it under the radiator, this page lays out every number.

The plant

Your plant tracks three needs: light, water, and heat. Each one is a value from 0 to 100. There is also a friendship score that only goes up.

The status bars show each need in green, yellow, or red. The colors are not cosmetic — they directly drive how fast your friendship grows.

Range	Color	What it means
40–60	green	The sweet spot. Friendship grows at full speed if all three needs are here.
30–40 · 60–70	yellow	Drifting. Friendship growth is cut to half speed.
10 or below · 90 or above	red	Critical. Friendship growth stops completely until you fix it.

Friendship growth

Friendship climbs at a base rate of 0.1 per second, multiplied by:

1.0x when all three needs are in the green band
0.5x when any need is yellow (and none are red)
0x when any need is red

Standing inside certain regions (sunlight, open window in rain, etc.) adds extra friendship on top of that, but the same multiplier applies — a red bar shuts off bonus growth too.

Passive drain

Even with the plant sitting on a neutral patch of desk, two needs slowly drain:

Light: −2 per second
Water: −0.2 per second
Heat: 0 per second (heat only changes when you push it)

Light drains the fastest, which is why the window and the lamp are doing most of the work for you.

Regions

Most of the room is empty space. The active patches are listed below. All numbers are per second, applied while the plant fully overlaps the region. Partial overlap scales linearly — the game samples 16 random points inside the plant's box, and you get the fraction that landed inside the region.

Two regions can overlap. If you park the plant where the lamp cone meets a sunbeam, both effects stack. The fan area and the radiator area cover most of the desk — pay attention to which switch is on.

Window — sun

Active by default at game start.

Variant	Heat	Light	Water	Friendship
Window closed	+0.3	+3.0	−0.2	+1.0
Window open	+1.0	+4.0	−0.5	+3.0

Opening the window during sun is the single highest-friendship spot in the game, but it also dries the plant out fastest.

Window — cloudy

Variant	Heat	Light	Water	Friendship
Window closed	0	+1.8	−0.3	+0.6
Window open	−0.2	+2.2	−0.5	+1.0

Opening the window in cloudy weather lets in a touch more light but also a cool breeze that nudges heat down.

Window — rain

Variant	Heat	Light	Water	Friendship
Window closed	0	+1.8	0	0
Window open	−0.2	+1.0	+1.0	+2.0

Open window in the rain is the only way to passively gain water from the window. The closed-window rain region is also much smaller — only the strip right by the glass — because the rain isn't reaching most of the room.

Lamp

Active when the left wall switch (the one near the lamp) is on.

Region	Heat	Light	Water	Friendship
Lamp cone	0	+2.3	−0.1	+0.1

A backup light source for cloudy days and rainstorms. Doesn't add heat, only a tiny water nibble. Friendship bonus is small — the lamp is for survival, not score.

Fan

Active when the right wall switch is on.

Region	Heat	Light	Water	Friendship
Fan cone	−1.0	0	−0.1	0

The cone is wide — it covers most of the desk. Useful for cooling the plant down, especially when the radiator is loud.

Sink

Active while the sink is running (tap the sink to toggle).

Region	Heat	Light	Water	Friendship
Under the faucet	−20	0	+30	0

The strongest effect in the game by far. Water shoots up almost instantly, but heat plummets just as fast — a couple of seconds under the tap and your plant goes from warm to frigid. The region is small (just the area directly under the faucet) so partial overlap is the norm.

Radiator

Activates on its own. After the tutorial finishes the radiator first kicks on around 80 seconds in, then cycles roughly 30–45 seconds on, 50–80 seconds off. Returning players see the first activation sooner (~15–35 seconds).

Region	Heat	Light	Water	Friendship
Left side of room	+2.0	0	−2.0	0

Covers the entire left half of the room and rises to the ceiling. The fan cancels most of the heat if both are running. Drink before you sit there.

Weather

The day starts sunny. After the tutorial, the weather cycles on its own:

Stays sunny for 60–90 seconds, then turns.
60% of turns go to cloudy, 40% go to rain.
Non-sun weather lasts 30–45 seconds before drifting back to sun.
Transitions cross-fade over 2 seconds; the new region activates 1 second in.

Rain has its own ambient sound whether the window is open or closed — a soft patter through the glass, or a louder rush if you let it in.

Putting it together

A few things that fall out of the numbers:

The sweet spot for friendship is having all three bars in the green band (40–60). Maxing a bar is actually worse than balancing it — 95 is red and freezes growth.
Light drains 10x faster than water when nothing is acting on the plant. If you tuck the plant in a corner away from everything, light dies first.
Open window + sun is the highest sustained friendship gain, at +3 per second on top of the green-band bonus. But water drains at −0.5, so plan a sink visit every minute or so.
The sink is a precision tool, not a parking spot. A full second under it adds 30 water and removes 20 heat. Two seconds and you've overshot both.
Rainy + open window is the only passive water source. Worth catching when it happens.
Partial overlap is real. If you straddle a region's edge, you get a fraction of the effect. Useful for the sink especially — sit half-in for a gentler refill.