What this is
A deep water culture (DWC) hydroponic garden built to grow 2–3 high-value herbs in an apartment with near-zero intervention. Roots sit in an aerated nutrient reservoir; an ESP32 reads the sensors and switches the pumps and light; Home Assistant runs the grow logic locally so the plants survive any internet outage; and this page mirrors it all through Cloudflare.
How it runs itself
☀️ Light
14 h photoperiod on a relay — on at dawn, off at night.
🫧 Aeration
Air stone runs continuously; the single most important thing in DWC.
🔁 Circulation
Water pump mixes the solution 15 min every 2 h.
🪣 Auto top-off
A float switch triggers a refill pump; alerts you only when the jug is empty.
The crops
Two water-loving, DWC-native herbs with complementary growth habits — both root from cuttings (no germination lottery), tolerate pH/EC drift, and love Bengaluru's warmth. High-value, hardy, and cut-and-come-again — the ideal pair to prove an autonomous rig before graduating to something fussier.
🌾 Lemongrass
Tall clumping aromatic (60–90 cm). Roots from a market stalk. High-value fresh & dried; the light rides an adjustable riser to track its height.
🌿 Rau răm
Low, sprawling Vietnamese coriander. Semi-aquatic — loves permanently wet, aerated roots. Cut-and-come-again.
The stack
Edge
ESP32 · ESPHome · DHT22 · DS18B20 · float switch · 4-ch relay
Brain
Raspberry Pi · Home Assistant automations
Cloud
Cloudflare Worker · D1 · KV · Pages
Structure
3D-printed PETG lid · net cups · sensor mount