1Ventilation

This is the single most important piece of hardware, and the one people most often under-spec. The Nexus can only dim a fan that's already the right size for the space. Undersized fan + smart hub = 100% duty cycle forever = unhappy plants and angry support emails.

Inline extractor fan

Sits inside or outside the tent, pulls air through a carbon filter and ducts it away. Sizing depends on tent volume, lighting heat, whether you run CO₂, and how much ducting you use. Use our free fan sizer to get a specific CFM number — takes 30 seconds.

Carbon filter (optional but usually wanted)

Strips odour from the exhaust air before it leaves the room. Match the filter inlet diameter to the fan — don't try to fit a 4" filter on a 6" fan with reducers, it kills airflow. Replace the carbon every 12–18 months; used-up carbon lets everything through.

2Climate hardware

Humidifier

Most grow tents run dry under lighting. A mid-range ultrasonic humidifier (3–5 L capacity) plugged into one of the Nexus's channels is enough for anything up to 1.5 m. BudMaster uses VPD targeting, so the humidifier runs only when the actual leaf vapour pressure deficit needs it — not on a fixed schedule.

Dehumidifier (late flower, winter)

Once plants are transpiring hard in late flower, or if you're growing through a damp UK winter, you'll swing the other way and need to extract moisture. A 10–20 L/day compressor dehumidifier switched via a spare channel handles a 1.2 m tent. For smaller spaces, a Peltier unit works but is less efficient.

Heater

Only needed if your room drops below ~18 °C at lights-off. A small 500–1000 W oil-filled radiator on a channel beats a fan-heater — no hotspots, no fire risk from dust on the element.

3Lighting

The Nexus dims any LED fixture with a dimmable driver. Most modern grow lights have one — check for a dimming port before buying.

Light sensor

The Nexus ships with a light sensor in the sensor pod. Hang the pod at canopy height so it reads the actual light reaching your plants (PAR). The Nexus then auto-dims the light to hit a daily light integral (DLI) target, so you're not over- or under-lighting.

4Power & cabling

Power supply (PSU)

The Nexus is powered by a 12 V DC supply — any regulated 12 V / 3 A unit does the job. Use one from a reputable brand (Mean Well is the gold standard). Avoid no-name bargain-bin bricks — grow tents run 24/7, and cheap power supplies are behind most flaky-sensor headaches.

Sensor cable (for the triple-sensor pod)

The triple-sensor pod connects to the Nexus with a plug-in 4-wire cable. It comes with 2 ft as standard — long enough to hang the pod 12″ below your light. Sensors will run up to 30 m, so if you need longer (a larger room, or extra rooms added via a router), Cat 5e or 4-core alarm cable does the job.

Mains wiring

All your fans, heaters, humidifiers, etc., plug into standard UK 13 A sockets. BudMaster's screw terminals are 2.5 mm² rated — you wire the appliance cable tail into the controller. If you're not comfortable with mains wiring, hire a qualified electrician. Mains voltage in a damp grow tent kills.

5Sensor placement

Where you put the sensor pod matters more than the sensor itself. Even the best CO₂ sensor reads rubbish if you hang it wrong.

• Hang the pod at canopy height. Plants live in that air — not at the top of the tent, not on the floor. VPD, CO₂, humidity and light readings all depend on this.
• ~12″ below the light. Far enough that the sensor doesn't read direct IR from the lamp, close enough to track the environment the plants actually experience.
• Not directly in airflow. A sensor sitting under the extraction fan reads the outside air blowing past. Place it in the body of the tent, not at a vent.
• Soil sensor: bury the tip 6–8 cm into the root zone. Not at the edge of the pot — roots don't grow there for the first 3 weeks. Centre of the pot, mid-depth.

6Smart plugs — for awkward kit

The Nexus's channels dim things smoothly — great for fans and LEDs, useless for kettles, water pumps or anything with its own controller. For those, use a smart plug the Nexus can switch on/off over your local network via its open API.

Compatible with any smart plug that takes commands on your local network — we recommend:

• Shelly Plug S — tiny, local-network only, no cloud. Our favourite.
• Open-firmware plugs — if you're comfortable flashing firmware, any generic Chinese plug (Sonoff S31 etc.) works a treat.
• Avoid: anything that requires a phone app + cloud account (TP-Link Kasa, Alexa-only plugs). Defeats the "no cloud" principle of BudMaster entirely.

7Pre-grow checklist

Before your first seed goes in, run through this:

• ☐ Fan sized correctly (use the calculator) and running, dimmable from 30% to 100%.
• ☐ Carbon filter fitted inline, airflow direction labelled.
• ☐ Humidifier full of distilled or RO water (never tap — it fouls the diaphragm).
• ☐ Light hanging at the right height for veg (60+ cm) and on a timer or controller channel.
• ☐ Sensor pod at canopy height, not in direct airflow, 12″ below the light.
• ☐ Nexus connected to your network, dashboard loading at its local address.
• ☐ RCD confirmed in the socket chain you're powering from.
• ☐ Tent tested at VPD targets for 24 hours empty before planting — if the climate holds steady, you're good.
• ☐ Chat widget bookmarked (bottom-right of every page on this site) — ask us anything during your first grow.