The first result from the TerraSens grow tests. One cultivar, the same kind of pot, one variable: the light.
Window light≈100 PPFD
TerraSens light≈500 PPFD
Specimen 01 · Ocimum basilicum 'Red Rubin'Day 38
The light comes from specially selected LEDs: deep red plus warm-white full spectrum. PPFD (photosynthetic photon flux density) measures how much of the light plants use for photosynthesis actually reaches the leaf, in µmol per m² per second. Measured at leaf height with the Photone app.
Setup
Two 'Red Rubin' basil plants of the same cultivar, in the same kind of pot. One grew on a bright windowsill, the other under the TerraSens light. We measured the light at leaf height with the Photone app: about 100 µmol/m²/s at the window, about 500 under the lamp.
Result
Under the lamp the leaves turned deep purple, the colour 'Red Rubin' is grown for. On the windowsill they stayed mostly green with purple veins.
Numbers
Window ≈100 PPFD, lamp ≈500 PPFD. The lamp runs 16 hours a day (6:00 to 22:00), which gives the plant roughly 29 mol/m² of light per day (the daily light integral, DLI). Next time we also log the window through the whole day, because daylight changes by the hour.
What it means
'Red Rubin' only colours up properly under strong light. The selected LEDs and their arrangement give it that light on a shelf, with no greenhouse and no purple glare.
Next
Grow test 02: 'Purple Ball' basil from seed, on the windowsill and under the lamp. Sown on 23 September 2026, result around mid-November.
Grow tests
Follow every test, from seed to result.
The first lamps arrive in Q1 2027. Followers see the design first and get the result of every test: one email per test.
Window light≈100 PPFD
TerraSens light≈500 PPFD