VIVOSUN GrowHub: What the App Does and How to Set It Up

Most grow tents are run by a handful of dumb boxes that do not talk to each other — a timer for the light, a speed dial for the fan, a plug-in hygrometer you squint at through the door. VIVOSUN's GrowHub replaces the lot with one controller and one app. This guide covers what the VIVOSUN app actually does, how to pair a hub in about five minutes, exactly which lights and fans it will drive — including several brands that are not VIVOSUN — and what happens when the Wi-Fi drops.

Who VIVOSUN are

VIVOSUN are a US indoor-growing brand — the strapline is Love Growing Green — and they arrived in the UK the way most people meet them: as the cheap grow tent everybody's first setup seemed to be built around. That is no longer a fair description of the range. Over the last few years they have built out a connected system, branded the Smart Grow System, where the lights, fans, humidifiers and sensors all plug into a central controller and are run from a phone.

That is the interesting part of VIVOSUN and it is the part this guide is about. Plenty of manufacturers sell a controller. Fewer sell a controller, a light, a duct fan, a clip fan, a humidifier and a dehumidifier that are all designed to be driven by the same box — and fewer still let that box drive their competitors' equipment too.

What a GrowHub actually is

A GrowHub is a small wall- or pole-mounted controller with a screen, a temperature and humidity sensor on a lead, and a set of ports on the bottom. Your devices plug into those ports with control cables rather than into the mains through it — this is the single most misunderstood thing about it. The hub is not a power strip. It sends control signals down data cables to equipment that has its own mains supply and its own control port.

That distinction is why it can do things a timer cannot. A timer can only cut power. A GrowHub can tell a fan to run at speed 4, tell it to move to speed 7 because the tent has drifted a degree warm, and dim a light to 60% — all without ever interrupting the supply.

The E42A is the one most people want. The dual-sensor arrangement is the reason: it reads conditions inside the tent and outside it, which is what makes its cleverer fan logic possible. More on that below.

The hub and its accessory

What the VIVOSUN app actually does

The app is free. There is no subscription, no premium tier and no paywalled feature set — VIVOSUN's own support documentation states it plainly, and it is worth saying because several competing ecosystems are heading the other way. Firmware and app improvements arrive as free over-the-air updates.

Six things are worth knowing about, roughly in the order you will use them.

1. Live readings, including VPD

The dashboard shows temperature and humidity from both sensors and calculates VPD — vapour pressure deficit — from them. VPD is the number that actually tells you whether your plants can transpire comfortably, because it combines temperature and humidity instead of treating them separately. If that is new to you, our guide to grow tent humidity and VPD explains what to aim for at each stage. Live data refreshes about once a minute, and you can pull the page down to force it.

2. Remote control of everything attached

Anything plugged into the hub can be driven from the app from anywhere with a signal — fan speed up, light dimmed, device off. This is the feature people buy it for and then use most on holiday.

3. Schedules and cycles

Lights get a straightforward on/off schedule. Fans can run on a schedule too, or on a repeating cycle — five minutes on, fifteen off, and so on — which is how you run intermittent extraction without a separate cycle timer.

4. Auto mode, which is the real upgrade

Instead of a fixed speed, you give the duct fan a high and low temperature and a high and low humidity. Below the threshold it sits in a standby zone — you choose in the app whether that means off, or ticking over at a minimum speed. Once the tent crosses the threshold the fan steps up, and the further past the threshold it goes, the harder the fan works. It is a proportional response rather than a blunt on/off, which is why a tent on auto mode holds a much flatter temperature line than one on a thermostat plug.

5. Advanced auto mode, which is cleverer still

This is the payoff for the second sensor, and you can only switch it on in the app — Settings > Additional Settings > Duct Fan Auto Trigger Mode. In advanced auto, the hub also looks at the air outside your tent before it decides. If the room is hotter or more humid than the tent, pulling more of it in cannot help, so the fan will not ramp up and the alarm icon flashes to tell you the outside environment is the problem, not the fan. Anyone who has spent a July afternoon watching an extractor run flat out and achieve nothing will recognise the situation. Our summer heat guide covers what to do about it.

6. Grow recipes, logging and alerts

Recipes let you set lights and fans by growth stage and hand the whole sequence to the controller — VIVOSUN supply pre-built ones written by their growers, and applying one is a single tap. Everything is logged, so you get a history of temperature, humidity and VPD rather than a single live number. And you can set ranges that trigger a push notification when the tent goes outside them, which is the feature that turns a dead fan from a lost crop into an inconvenience.

Setting it up, step by step

Allow about five minutes for pairing and rather longer for tidy cable routing.

1. Mount the hub

   It fits two ways: magnetically, onto the steel plate you screw to a tent pole, or straight onto a wall using the slotted hanging holes. Put it somewhere you can read without crouching.

2. Place the sensor properly

   The temperature and humidity probe is on a 3m lead. Hang it at canopy height, in open air, out of the direct beam of the light and away from the fan's intake. A probe sitting on the floor or taped to the tent wall gives you a number that is real but useless.

3. Connect your devices

   Match the cable to the port — the map is in the next section. Push connectors home firmly; a half-seated RJ11 reads as a missing device.

4. Power it

   Here is the part that catches people out. The hub draws its power from a connected AeroLight, AeroZesh or AeroWave E6 through the control cable — no separate power lead needed. If you are only connecting a non-VIVOSUN light or fan, you need the 12V adaptor, which is included with the individually boxed GH-E42A but not with every bundle.

5. Get your phone ready

   Two prerequisites, and both matter: you need a 2.4GHz Wi-Fi network and Bluetooth switched on. Bluetooth is how the phone hands the Wi-Fi credentials to the hub during setup. If your router runs a single combined 2.4/5GHz network name, you may need to split the bands temporarily.

6. Pair it

   Search "VIVOSUN" in the App Store or Google Play, install the app, create an account and follow the in-app pairing flow. Once it is on the network the dashboard populates within a minute.

7. Assign each device to its outlet

   Tell the app what is plugged into what, then set your schedules. You can assign two of the same device type to different outlets — two fans on two ports is a normal, supported arrangement.

What you can plug into it

Three connector types, and they are not interchangeable.

It is not a closed system, and that is unusual

The part that surprises people: the GrowHub will drive plenty of lights and fans that are not VIVOSUN. Their published compatibility list covers, via the RJ11 port, fixtures from Mars Hydro (TS, FC, FC-E and SP series), Spider Farmer (G, SE and SF series), Phlizon, Viparspectra, Bestva, Flexstar, Grower's Choice, Hyphotonflux, Luxx, Medic Grow, Sunraise and Volt. On the fan side, AC Infinity Cloudline A, B, S and T series fans with a Type-C connector plug straight in, and older Molex-connector Cloudlines work through an adaptor.

So if you already own a Mars Hydro light and an AC Infinity fan, an £87.95 controller may well tie your existing kit together without replacing any of it. That is worth checking before you spend on a brand-matched system.

The devices that talk to it

Everything below is designed to be driven by a GrowHub. They all work perfectly well standalone, so none of this is wasted if you buy the controller later.

Light and air

Holding the climate

Watching the room

What happens when things go wrong

Any system that puts a phone between you and your equipment invites one fair question: what happens when the phone, the app or the internet is not there? VIVOSUN's answers are better than you might expect, and worth knowing before you need them.

The rest of the VIVOSUN range

Not everything VIVOSUN make is connected. The ventilation parts in particular are just good, sensibly priced kit — and the extraction kit is the easy way to get a matched fan and filter without doing the airflow maths yourself, though our fan and filter sizing guide is there if you would rather check.

Browse the full VIVOSUN range

Quick answers

Is the VIVOSUN app free?

Yes. It is free to download and free to use, with no subscription fee and no restricted tier — VIVOSUN state this explicitly in their own documentation. New features arrive through free app updates and over-the-air firmware updates.

Do I need Wi-Fi to use a GrowHub?

No. You can run the controller entirely offline using the buttons on the unit to control lights, circulation fans and duct fans. Wi-Fi adds remote access, live data, environmental logging, push alerts, grow recipes and advanced auto mode — so most people connect it, but nothing stops you using it as a very good standalone controller.

Will the GrowHub control my Mars Hydro or AC Infinity gear?

Very likely. VIVOSUN publish a compatibility list covering Mars Hydro TS, FC, FC-E and SP series lights, Spider Farmer G, SE and SF series, plus Phlizon, Viparspectra, Bestva, Flexstar, Grower's Choice, Hyphotonflux, Luxx, Medic Grow, Sunraise and Volt — all through the RJ11 port. AC Infinity Cloudline A, B, S and T fans with a Type-C connector plug in directly, and Molex-connector Cloudlines need an adaptor. Check your exact model, since some third-party fixtures support fewer daisy-chained lights or a narrower dimming range.

How many devices can one hub run?

Up to 12 AeroLights daisy-chained on RJ45, or 8 VS-series lights on RJ11, plus 4 duct or clip-on fans on the Type-C ports and one temperature and humidity sensor. You can also assign two of the same device type to two different outlets. If you run out of Type-C ports, the 2-in-1 splitter at £13.49 turns one into two.

Does the controller need its own power supply?

Usually not. It takes power through the control cable from a connected AeroLight, AeroZesh or AeroWave E6. If you are connecting only a non-VIVOSUN light or fan, you will need the 12V adaptor — it is supplied with the individually boxed GH-E42A but is not part of every bundle.

What is VPD and why does the controller show it?

VPD, or vapour pressure deficit, combines temperature and humidity into one figure describing how strongly the air pulls moisture out of a leaf. It is a more useful target than humidity alone, because 60% RH at 20°C and 60% RH at 28°C are very different conditions for a plant. The E42A calculates it live from its sensors, and our grow tent humidity guide covers the numbers to aim for.

What is the difference between auto mode and advanced auto mode?

Auto mode ramps the duct fan when the temperature or humidity inside the tent passes a threshold you set, and works it harder the further past that threshold it goes. Advanced auto mode — switched on in the app under Settings, Additional Settings, Duct Fan Auto Trigger Mode — also reads the conditions outside the tent. If the outside air is worse than the inside air, it will not ramp the fan up, and it flashes an alarm icon instead, because pulling in hotter or wetter air cannot fix anything.

Should I buy the E25 or the E42A?

The E42A at £87.95 if you want the full system: dual sensors, VPD, scheduling, auto mode, recipes and dimming. The E25 at £29.49 is the entry point — Wi-Fi and app controllable, supports Smart Grow System devices, and has an expansion port so you can add an E42 or E42A later. If the reason you are buying is climate automation, go to the E42A; the sensors are the point.

Brand names other than VIVOSUN are the trademarks of their respective owners and are referenced here only to describe compatibility. VIVOSUN claim no affiliation with them, and neither do we. Specifications and compatibility lists are those published by VIVOSUN at the time of writing — check your own model before buying.