Harvst’s Smart Mini Greenhouses are built to help you grow veg, salads and herbs even when space and time are tight. Below is a simple overview of how they work and the key add-ons that make them low-maintenance.
Why Smart Mini Greenhouses?
Not everyone can tend plants daily, but you can still raise crops with automation doing the heavy lifting. Harvst offers smart mini greenhouses in four compact sizes, ideal for courtyards, patios or balconies. Founded in West Wales in 2019 by electronics engineer Chris Tanner, Harvst started as a solution to windy, wild conditions — and grew into a full smart growing system.
Automatic Opener
Small, enclosed spaces heat up fast. The Sprout lid can be propped open manually, but an automatic opener is smoother and keeps temps stable.
What’s Included
The Solar, 3 Season and 4 Season models include an automatic opener as standard. If you choose the greenhouse-only model, you can add the opener at checkout.
How It Works
No mains power needed — a wax cylinder and springs lift the whole lid as the inside warms. Set the opening temperature between ~18–25°C by adjusting the piston.
Solar Power
Harvst’s Solar models run a sensor-based watering system without mains power or water.
Panel & Mounting
A compact 5 W panel (approx. 23 × 18 × 1.5 cm) comes with brackets, a 3 m cable and a two-pin connector for the control unit — long enough to mount for best sun.
Smart Watering
The panel charges the control unit’s battery. Using sensor data and timers, the controller opens electric valves (and an optional pump) to feed drippers — keeping plants watered efficiently.
Smart Control & Sensors
The Control Unit
There’s a solar-powered controller (with battery) for the Solar model, and a mains version for 3 Season and 4 Season models. Setup is via a web app (iPhone, Android, laptop or desktop). If your greenhouse is within Wi-Fi range, you can monitor and tweak settings remotely.
Air & Soil Sensors
An air temperature sensor (1 m cable) is standard on Solar, 3 Season and 4 Season models. For finer watering control, add soil moisture sensors so the system waters based on actual substrate moisture, not just time.
Increasing Temperatures
Adding gentle heat extends your season and speeds germination. The 3 Season and 4 Season Sprout models include a safe, low-voltage heating cable.
Heating Cable
The 12 V cable is 4 m long, waterproof and self-regulating to a ~50°C setpoint (it draws more power on colder days to maintain temp). Lay it on the shelf and place seed trays or plant pots on top to warm the compost and gently heat the air.
Note: don’t allow direct contact with foliage or roots.
Power Limits
You can buy an extra heating cable for 3/4 Season models (not Solar — the panel can’t supply it). The mains control unit supports up to ~150 W total. Each cable uses ~60 W at max, so typically two cables is the limit if lights are off. When lights are on, the controller prioritises power (often allowing only the top cable).
LED Grow Lights
Use lights to grow year-round or when your spot lacks natural light. Harvst supplies low-voltage waterproof LED strips designed for the Sprout shelving.
Specs & Fit
On 4 Season models, 10 W strips (~50 cm) mount under mesh shelves to light the level below and add a touch of warmth. Shelf spacing is ~28 cm; raise seedlings closer to the strips at first, then lower as they grow. The control unit can support up to 12 lights depending on your heating setup and includes splitter cables for easy daisy-chaining.
Timing
Lights plug into the control unit and can be scheduled via the onboard timer (two runs per day). On warmer days, the automatic opener helps dump excess heat.