Frequently asked questions

A grow room controller automates the fans, lights, humidifier, heater and CO₂ valve in your tent or room so plants get consistent conditions day and night. If you're running more than a single fan on a mechanical timer, you'll almost certainly grow better with a controller — and one BudMaster Nexus replaces what would otherwise be three or four separate boxes from different brands.

Vapour Pressure Deficit — the difference between how much water the air could hold and how much it actually holds at the current temperature. It's the single best number for telling whether your plants can transpire efficiently.

Low VPD (~0.4 kPa) suits seedlings; high VPD (~1.4 kPa) suits flower. Nexus targets a VPD range you set, automatically adjusting extract fan speed to hold it. See the VPD calculator to find your target.

DLI (Daily Light Integral) is the total light energy your canopy receives in a day, measured in mol/m²/day. Most controllers let you schedule on/off times. Nexus goes further — it measures actual PAR at the canopy with a light sensor and trims a dimmable LED automatically to hit your DLI target.

Result: every day's light dose is the same, even as your plants grow taller and canopy closer to the fixture.

Nexus includes dual-safety CO₂ control — a software timeout and a separate independent hardware backup that cuts the valve independently of the main software.

That said, CO₂ enrichment is still a real hazard and you are responsible for safe installation in a properly ventilated space. A printed CO₂ safety brief comes with every Nexus.

Full guide: CO₂, done right, is a game changer → — what it does, what it needs to actually work, and the safety reference levels.

No. The dashboard is served directly by the Nexus on your local network. Once Wi-Fi is set up, it runs offline indefinitely — schedules from its own clock, sensors read locally, decisions made locally. Internet is only needed for firmware updates (when you click update) and optional BudMaster Mobile App notifications.

No. No account to create, no subscription, no monthly fee. Ever. The Nexus works if our company disappears tomorrow — the firmware is open-source and the dashboard is on your device. See the privacy policy and the "what if BudMaster goes out of business" question below.

Probably, yes. Any speed-controllable inline fan, any dimmable LED driver (Mars Hydro SP, Spider Farmer SE, HLG, Growcraft and most other brands), any on/off humidifier or heater via smart plug.

BudMaster is brand-agnostic by design — see the compatibility page for the full list of tested gear.

Yes. BudMaster works with Home Assistant out of the box (disabled by default; toggle on in Settings). Every sensor reading and every control channel is exposed. No Home Assistant cloud account needed — local only.

Yes. A full open API is built in, documented at /api.html and on the Integrations page, and also on the Nexus itself. Every sensor readable, every target settable, every action triggerable over your network.

Air: a temperature/humidity sensor, a barometric pressure sensor, a CO₂ sensor and a light sensor (logs PAR / DLI).

Soil: an industrial 7-in-1 soil sensor — temp, moisture, EC, pH, N, P, K.

All wired. No wireless sensors in the base kit — reliability over convenience.

Safety. 12V DC is classified as Extra-Low Voltage (SELV) under BS 7671 / IEC 60364 — non-notifiable under UK Part P Building Regs. It can't give you a shock through dry skin. Grow-tent damp environments are inherently safer. There's no ageing mains wiring inside the case. And the dangerous bit (the wall PSU) is a cheap replaceable commodity.

Full engineering rationale: Why every BudMaster runs 12V DC end-to-end → — safety, variable-speed control, push-pull airflow, cost, noise, and power efficiency.

No. Any regulated 12V DC supply does the job. Mean Well is the gold standard. Cheap unbranded bricks are the single most common cause of flaky sensor readings — avoid them.

A bespoke UK-designed board with the brain — a fast dual-core processor — plus Ethernet, PoE, Wi-Fi, and inputs and outputs for your sensors and equipment, all on one board. Schematics are open — you can inspect or repair anything you own.

Most customers are reading sensor data in under an hour. Wall-mount the Nexus, plug in the triple-sensor pod, wire your fans and PSU via screw terminals, run the first-boot Wi-Fi setup on your phone. Stage presets load in two clicks from there.

No. The Nexus runs on 12V DC safe-touch voltage — no mains on the board. You wire fans and sensors via screw terminals; if you can wire a light switch, you can wire this. A printed quick-start comes in the box, plus a setup video link with your despatch email.

No, and they never will. OTA firmware updates are free for the life of the product. You initiate them — we don't push. Signed binaries, local-network-only delivery. Release notes and downloads at /firmware.html.

Yes. Sensor readings never leave your network. We collect no telemetry, track no usage, never see your data. Order details (email, delivery address) are retained for fulfilment and warranty only. Full breakdown on the privacy policy.

Fair. We're a new company and we'd rather earn that trust with the product than with a marketing budget. The hardware has been in development for over a year with prototype units running daily. Firmware is open-source, the feature list is publicly documented, the schematics are on this site.

If it doesn't do what we say, return it inside 14 days for a full refund. If it breaks within 12 months from causes that aren't your fault, we replace it. Every established brand was unknown once.

Those companies make their money selling fans and lights. Their controllers exist to lock you into buying more of their equipment — that's why the AC Infinity Controller 69 only talks fluently to AC Infinity gear, and TrolMaster needs a £50–£200 proprietary adapter for every brand of equipment you want to integrate.

BudMaster exists because we couldn't find a controller that did what we needed without forcing us into one brand's ecosystem. Our incentive is to make the best controller possible, not to sell you fans. We don't sell fans. We don't sell lights. The controller is what we sell — and the only way it succeeds is if it's worth buying.

Every email goes to the person who designs the hardware, writes the firmware, and ships the box. No ticket queues, no AI chatbots pretending to be human, no form letters, no support number that bounces between three time zones. If it doesn't work, we want to know — and we want to fix it that day.

Read any forum thread about AC Infinity, Mars Hydro, or Spider Farmer support and you'll see why we picked this approach. Replies typically arrive inside 24 hours, Mon–Fri.

Yes — three ways. The control-panel page shows the actual Nexus dashboard live (synthetic data, real UI). The app page shows the mobile app rendering at iPhone widths. And we'll happily do a 15-minute video walkthrough if you'd rather see real sensor data and ask questions live — email hi@budmastergrow.com with a couple of times that suit you.

Cross-shop. The closest functional rivals are the AC Infinity Controller 69 Pro+ (less feature coverage, AC-Infinity ecosystem only), TrolMaster Hydro-X Pro (~£430 base, plus £50–£200 per integration adapter), and Pulse Pro (£400, monitor-only — doesn't control anything). The Inkbird ITC-608T at £100 is a thermostat with VPD display, not a controller.

If you'd rather DIY: the brain, four sensors and a dehumidifier-grade smart plug will cost you ~£30 in parts and 40+ hours of firmware work. We've already done the firmware. That's mainly what you're paying for.

Nexus and the Mini / Mid / Max channel routers are coming soon — we're finalising the first production run. Join the waitlist and you'll be first to hear when they go live, including pricing and batch position. One email, no spam, cancel anytime.

Pricing is coming soon and goes to the waitlist first. Join the waitlist to be told the moment Nexus and the routers are live. If you want a sense of the value, the "how does it compare" question above lines us up against the closest rivals.

Yes — worldwide from day one. UK shipping is free; flat-rate shipping to the EU, US/Canada and Aus/NZ. Import duties and VAT at destination are the buyer's responsibility. See the shipping page for full details.

Before despatch: yes. Reply to any order email with your change request — address, quantity, or full cancellation — and we'll sort it. After despatch: see the shipping & returns page.

12 months from delivery covering PCB and pre-soldered components — on top of your statutory rights under the Consumer Rights Act 2015. Not covered: reversed polarity, liquid damage, overvoltage, firmware modification. See shipping.html § 9 for the full terms.

Email hi@budmastergrow.com within 48 hours with your order number, a description of the fault and a photo. We respond with return instructions within 24 hours. Sensors carry a 30-day fault-only return window.

Your Nexus keeps working. The firmware is open-source, the dashboard runs on the Nexus itself, and nothing depends on our servers. You can fork, modify, or fix anything in perpetuity.

This is a deliberate design choice — no lock-in, no hostage situation. One of the core reasons we built it this way.