Sunpatch
Every seed packet is written in hours of direct sun. Almost nobody knows what their own garden actually gets — so the tomatoes go in the shady corner and never ripen.
The label said full sun — six or more. Your fence takes the rest.
Other sun apps show you where the sun is. That is the easy half. The half that decides whether anything grows is what stands in the way. Point your phone at the top of the fence, the garage, next door's lime tree — or just enter how tall and how far — and Sunpatch builds the skyline around that exact spot.
The app walks the day minute by minute and counts only the light that actually reaches you. You get the total, the first and last sun, the longest unbroken stretch, and the same figures for every day of the year — so you can see the bed that bakes in July sit in shadow from October.
Full sun, part sun, part shade, full shade — the same bands the labels use. 135 plants matched against the light you actually have, and a plain list of what will not work.
Every calculation runs on your phone, so measuring, the charts and the whole plant library work in aeroplane mode without an account. Signing in is optional and does one thing: it backs your spots up, so a lost phone is not a lost season. No ads, no analytics.