Smart Growing Automation
One hub to run your whole grow. Industrial sensing, beautiful software, UK-built. Add Mini, Mid & Max channel routers as you scale. No cloud, no subscriptions.
Coming soonOne Nexus scales from a single tent to a full facility — start small, grow into a beast, never replace the brain.
The brain of the room — full VPD climate control, industrial sensing, CO₂ and lighting logic, the dashboard and mobile app. Its two onboard channels run a single tent on their own; add routers when you need more.
Coming soonTwo extra output channels for the Nexus. Add fans, a heater or a humidifier as your grow grows.
Coming soonFour channels of expansion. Drive circulation fans, dimmable lights and climate plugs from the same hub.
Coming soonEight channels for a fully kitted sealed room — every fan, light, heater and CO₂ valve, all driven from one Nexus.
Coming soonThe same hub, two interfaces. Both included with every Nexus. No extra cost.
The on-device dashboard. Open any browser on your home network and you’re straight at the live readings — no app to install, no account to create, no internet required.
Your grow room in your pocket. Watch trends roll in over hours and days — VPD, temperature, humidity, CO₂, light. Tune fans, change stages, get alerts from anywhere.
BudMaster Nexus is a UK-built smart grow room hub. It’s a true VPD controller: it reads temperature and humidity from a factory-calibrated sensor, computes leaf VPD using the standard formula (with a configurable 2 °C leaf-cooler offset), and drives fans and exhausts to your VPD target. Lights track your DLI target. CO₂ doses to your ppm target. Three closed loops, one hub. Whether you’re running a single grow tent in a 60 × 60 box or a fully kitted sealed grow room with Mini, Mid and Max channel routers added, the dashboard, the firmware and the API are exactly the same.
Start with a Nexus and a single tent. Add a soil probe when you start caring about pH. Add CO₂ when your room’s sealed. Add a Mini, Mid or Max router when you need more channels. Same dashboard, same firmware, same hub. Never throw kit away. Never start over.
Buy what fits your grow today. Upgrade in place when it doesn’t.
Seven kinds of grower keep finding their way here. See if any of them sound like you.
You’re running a single tent and you don’t need a wall of channels. A Nexus on its own gives you VPD-driven fan control, grow-stage presets, and the mobile dashboard — no routers required.
Coming soonYou already know what proper VPD does. Nexus lets you set a complete week-by-week schedule — different VPD, temp, RH, CO₂, DLI per week — and it auto-advances as the plants mature. Stop fiddling with sliders every Sunday.
Coming soonThe big-name commercial controllers want you to buy proprietary integration adapters per accessory and lock you to Ethernet. Add a Mid or Max router and Nexus drives every fan, light, heater and CO₂ valve in a fully kitted sealed room — same VPD/CO₂/DLI logic, no proprietary modules, no Ethernet-only restriction.
Coming soonFull REST API on every endpoint. Native Home Assistant via MQTT auto-discovery. ESPHome YAML in the box. Open firmware with OTA updates. No cloud, no account, no telemetry. Wire up Grafana, Node-RED, or roll your own dashboard — the data’s yours.
Coming soonYou bought AC Infinity fans, then found out the controller only talks fluently to AC Infinity gear. BudMaster works with any 12V fan, any dimmable LED driver, BudMaster WiFi plugs (or any smart plug), any soil sensor. No vendor lock-in. No app-only limit. No 60-day Wi-Fi drop-out.
Coming soonYou shouldn’t need a botany degree to keep plants alive. Tell BudMaster which week you’re in — Seedling, Veg, or Flower — and the controller targets the right VPD, RH, temperature and light hours for that stage. Three years of grow-forum reading, distilled into one button. Far fewer ways to get it wrong.
Coming soonComing soon: Sovereign mode — the controller speaks Nostr direct to a relay you control (or any public one). No vendor cloud, no Telegram in the loop, no account needed. Bring your own Nostr client (Damus, Amethyst, web). We don’t see your grow, and we mathematically can’t. Pay in Bitcoin to match.
In developmentBuilt by growers, for growers. No cloud, no subscriptions, no data harvesting.
Real-time vapour pressure deficit from temperature, humidity and barometric pressure. Fans respond to actual plant stress, not arbitrary thresholds.
Closed-loop light control that dims to hit your daily light integral target. Sunrise and sunset ramps built in. No other consumer controller does this.
Up to 16 weeks of staged targets that auto-advance. Research-backed presets for clone, veg, flower and auto.
Automatic night flush, botrytis prevention, temperature drop management. Your room stays dialled while you sleep.
Your grow room in your pocket. Check temps, tune fans, change stages, get alerts — from anywhere on the planet. Encrypted, free, no subscription.
Six-factor 0–100 environment score. Know at a glance whether your room is dialled or drifting. Auto-generated grow diary tracks every session.
Every reading your plants need, on one dashboard.
Most controllers react to single readings — temperature too high, turn on a fan. That's like driving by only watching the speedometer.
BudMaster is built on two measurements that actually matter: VPD and DLI. VPD (Vapour Pressure Deficit) tells you how efficiently your plants are transpiring — it's the single best indicator of whether your climate is helping or hurting growth. DLI (Daily Light Integral) tells you the total light energy your plants receive each day — not just how bright your light is, but whether your plants are getting enough over the full photoperiod.
Every decision BudMaster makes — fan speeds, light dimming, CO2 dosing, climate plug control — is driven by these two numbers. The charts below are the same reference data built into every Nexus. Use them to understand what your plants need at each stage.
Below ground, north-facing, brick walls. Ambient runs cold and wet — humidity in the high seventies year-round, temperature swings between 11 °C in winter and 18 °C in summer. The walls weep. The neighbour’s shower next door pushes up the RH every morning at 7am.
What BudMaster does: ramps the extraction fan to pull damp air out faster, dims the LED to bias warmth into the canopy without overheating, runs the dehumidifier plug whenever VPD drops below the seedling target, and times the heater to pre-warm the room before lights-on so the plants don’t hit cold dew at sunrise.
Top-floor flat, south-facing, the loft cooks all summer. Ambient runs hot and dry — high twenties on a normal day, mid-thirties in July when the sun's directly on the roof tiles. The tent traps the LED's heat. RH bottoms out under 30% by mid-flower.
What BudMaster does: opens the intake and exhaust together to dump heat fast, dims the LED progressively as canopy temperature climbs (50 % at +4 °C, full cut at +7 °C), runs the humidifier in bursts to lift RH back into the green, and shifts the photoperiod to start at dawn so the lights are off during the hottest part of the afternoon.
1.0 kPa is 1.0 kPa whether you’re fighting damp in a Lancashire cellar or heat in a Sussex loft. The whole point of BudMaster is that you tell it the plant’s target and the controller works out what to do with your equipment to get there. You stop manually pulling fan speed dials and stop guessing whether to crack the tent. You read the dashboard once a week instead.
An honest timeline. No hockey-stick promises — just what tends to happen with the first batch of growers we’ve worked with.
Plug in the carrier, scan the QR for WiFi, the dashboard shows live sensor numbers from the moment it boots. No account, no app store. You’ll see your real ambient T, RH, VPD, CO2, and PAR before you’ve finished your tea.
Pick a stage (Seedling / Veg / Flower) once. The controller tracks VPD against the target band and starts modulating fans and equipment in the first hour. Most growers find their climate stable inside the green zone by the next day.
The 7-day trends page is what catches the issues you didn’t know you had — midday VPD spikes, the night-time RH crash, the photoperiod creep. Most growers find at least one “ohhh” moment in the first weekly review.
The honest answer on yields: it varies. What’s consistent is that growers report fewer stress events, fewer manual adjustments, and a lot less anxiety opening the tent. The plants look right because the climate is right, day after day, while you’re asleep.
Vapour Pressure Deficit — the key to optimising plant transpiration. Select your grow stage to see ideal ranges.
BudMaster automates VPD control — adjusting fan speeds in real time to keep your grow room in the green zone.
Daily Light Integral — total light energy your plants receive per day. Find your PPFD and photoperiod to check your DLI.
BudMaster tracks DLI in real time and auto-dims your lights to hit your daily target — closed-loop control, not guesswork.
The VPD and DLI bands above aren’t marketing-friendly approximations — they’re the consensus distilled from peer-reviewed plant-science literature, breeder data, and commercial-controller defaults. The same ranges are baked into every BudMaster firmware build.
Primary sources: Dr. Bruce Bugbee (Utah State University Crop Physiology Lab) · Cornell University Controlled Environment Agriculture (CEA) Program · Wageningen University & Research (greenhouse horticulture, NL) · Dr. Marc van Iersel (University of Georgia — DLI & light-saturation research) · Fluence Bioengineering research papers · Photone / GrowLightMeter DLI compilation · GrowSensor week-by-week guide · FloraFlex temperature-differential guidance · California LightWorks commercial DLI targets · AC Infinity Controller 69 stock presets (sanity check).
Because your plants deserve better than a timer and a thermostat. And your tent deserves better than mains voltage.
Your sensor data never leaves your network. No account, no telemetry, no monthly fee. Works the day we go out of business and the day after that.
CO₂ runs on its own independent safety circuit — if the software crashes, the valve still shuts off. 12V DC throughout. No mains in the tent.
Firmware open, REST API documented, schematics inspectable. Works with your existing fans, lights, sensors. No vendor lock-in. No app store dance.
Want updates on new features, firmware releases and launch availability? Drop your email and pick which unit you’re interested in. One email a month, max — no drip campaigns, no third parties.