How does the Harvst solar watering system work?

The brains of the system is the electronic control unit, designed and built by Harvst in the UK. It uses a combination of environmental data and timers to turn on electric water valves (and optionally a pump) which are connected to industry standard irrigation parts.

The built-in battery is charged by a small solar panel. A mains powered version is also available, which lets you run low voltage heaters and grow lights.

Settings are managed via your smartphone using a web app, either on your home WiFi network, or on a network transmitted by the box itself.

A typical installation is shown in the drawing (with options for inline and submersible pumps both shown).

Two separate runs of 13mm LDPE distribution pipe are run around your greenhouse or polytunnel, into which you can fix sprayers / misters directly, or add 4mm dripper lines.

You can also connect a garden hose directly to the water valves instead of using a pump.

Versatile : dual zone irrigation

The electric water valves allow you to run two separate watering regimes; perhaps drippers for tomatoes, and sprayers for salads. Or you can use the two zones to extend the capacity of a single pump. Each zone can be controlled independently.

Precise : automatic timer watering

WaterMate lets you water each zone from 1 second to 5 minutes, from twice a day to once a week. Timings are managed using the web app. The precise control over timing makes WaterMate suitable for a range of irrigation purposes, including the watering of microgreens and hydroponics.

Efficient : weather responsive

WaterMate can be set up to use environmental data from its sensors to save water on cool days, and give extra on hot days to help your plants grow better. On a hot and sunny day, choose to water more. On a cool day, don’t water as much.

Manage and monitor your greenhouse from anywhere

WaterMate is a smart solar watering system: the control unit can connect to the internet and send your greenhouse data to the Harvst cloud. Using the Harvst web app, you can monitor and manage your automatic watering system from anywhere.

You can also set it up to send you email alerts when temperature / soil moisture / humidity go out of range. If you are using a pump, it will also tell you when the pump is empty.

Read more about our remote greenhouse control and monitoring.

A powerful solar powered watering system

The control unit, water valves and add-on pumps are powered by the built in battery, which is charged by a small solar panel.

The Harvst Pro pump can provide 3 gallons per minute at 35 psi. That’s a significant amount of water.

Using our supplied pumps, the system can water up to 10 minutes per day, assuming good summer sun. Our experience is that even a large polytunnel uses less than 5 minutes of watering, if it’s set up properly.

The WaterMate solar watering system core pack is compatible with these Harvst add-ons:

System specifications:

  • Control unit 190 x 120 x 45 mm with mounting holes
  • Built in 14.8v 2900mAh lithium ion battery
  • 10W solar panel 350 x 220 x 18mm
  • Solar panel brackets
  • Dual 12v electric solenoid with snap-on hose connector input and twin 12mm barbed outputs

What is a solar watering system?

We use the term “solar watering system” to describe an automatic irrigation system where the electronic controls AND the pump are powered by a battery, which in turn is charged by a solar panel. This means you can run them anywhere, without the need for a mains electricity connection.

The Harvst WaterMate solar watering system can be set up with a battery powered water pump, or you can use the solar core pack (this product) with a mains water tap. The electric water valves run off the battery in the solar powered control box.

Can I use a tap or garden hose

Yes. The solar watering core pack comes with dual water valves, which connect to a hose simply using a Hoze-lock compatible snap-on connector (supplied). You’ll need to leave the garden hose turned on all the time, in order for the electric valves to control the water flow into your greenhouse or polytunnel, so it would be handy to fit a 2-way tap splitter for you to use a hose elsewhere too.

Can I fit my own water pump?

Any 12V DC pump using less than 4 amps continuous current can be fitted to the pump output of the core pack. You’ll need to buy a suitable connector from us.

How much can I water with the solar core pack?

This all depends on the pressure and flow rate of your water source. If you’re using mains water, then you will have no problem watering up to a 40m2 polytunnel. 

The Harvst Mini pump is practical and simple; just drop it into a water tank either inside the greenhouse, or a water butt outside. It can power up to 16 sprayers (8 per zone) or 40 drippers (20 per zone).

The Harvst Pro pump is a lot more powerful, and provides a higher pressure. It will power up to 120 drippers (60 per zone), 30m of soaker hose, 40 sprayers (20 per zone), or misters for keeping your greenhouse or polytunnel cool, and the humidity up.

I would like a complete solar watering kit

We provide WaterMate Mini and WaterMate Pro as ready-to-fit solar watering kits, including hose, fixings, fittings, dripper line, nozzles … everything you need apart from water.

How far can my water tank be?

The mini pump needs to be placed in a tank right next to your greenhouse; not more than 4m of inlet hose before the water valves. The pro pump can bring water from up to 10m away, with a lift of 4m.

How does the low water level sensing work?

When your water tank runs out, and the pump starts running dry, it uses less power. The control box monitors this and can send you an alert by email – “top me up please!”