PILF
The PILF Scale

Two values on every plant. Eleven characters on a tag.

A shared vocabulary for what you can keep alive, without knowing a single Latin name. “I used to only manage a C. I’ve kept a B alive for three months.” “Mine’s a 3 and it’s thriving, so I can probably do a 2.”

Grade — how much neglect it forgives

A
Hard to kill on purpose. Forgives a month of nothing.
B
Forgives two weeks away, or one persistent bad habit — not both.
C
Wants a rhythm. Tells you loudly when it isn’t getting one.
D
Wants the right room and the right rhythm. Buy this one third, not first.
F
Not sold here. Somebody else will.

Everything on a PILF shelf is an A or a B. That’s a merchandising rule, stated out loud. A grade is about difficulty, never quality — a C can be the most beautiful plant in the room. It just wants more from you.

Light — described as a room, not a condition

1 / 5
A room with no window at all. A hallway, a bathroom, an interior desk.
2 / 5
There’s a window somewhere in the room. You’re across from it.
3 / 5
Within a few feet of a window. Most living rooms, most cafés.
4 / 5
Right beside a bright window, out of the sun’s actual path.
5 / 5
Sun on the leaves for hours. Almost nothing indoors wants this.

The number on a plant is the least light it’s happy with. More is fine, right up to the sun itself. “Bright indirect light” tells a first-time buyer nothing; “a few feet from a window” is a place you can point to.

The shelf, on the scale

PlantGradeLightWater
Golden PothosA2Every 10 days. Droopy is fine.
Heartleaf PhilodendronA2Every 10 days. It forgives a late one.
Marble Queen PothosA3Every 10 days. Droopy is fine.
Spider PlantA3Weekly-ish. Safe if the cat chews it.
PeperomiaB3Every two weeks. The leaves hold water.
Snake PlantA1Once a month. Less in winter.
ZZ PlantA1Once a month. It stores its own.
HoyaB4Every two weeks. Likes a tight pot.

Six of the eight are fine in a room with barely any window. That’s the whole merchandising argument.