Automatic watering in Harvst mini greenhouses
Our mini greenhouses are a complete growing system, with built in watering. Pipes are integrated with the shelves and aluminium frame, and connected to electrically operated water valves. Water is provided by either a pump (which goes into a small water tank or a nearby water butt) or a garden hose.
All models feature two separate watering zones; top and bottom. The top of the greenhouse is intended for starting seeds and low plants such as salads. This area is covered by misters / sprayers. The bottom of the greenhouse is intended for larger plants, and is covered by sprayers with a larger nozzle size.
Water pressure is provided by a small submersible pump (280gph, 12v, 45mm diameter) which drops into a tank or water butt next to the greenhouse. No priming is needed, which allows us to control the pumping time more precisely, knowing that the plants will actually be getting water rather than the pump just running to prime itself.
How our greenhouse watering system works
We’ve designed WaterMate (our greenhouse watering system) based on what we’ve learnt while developing our own mini greenhouses … it uses the same control system, sensors and water valves with a more powerful pump, designed for irrigating a larger area, and longer watering cycles.
- An inlet hose goes from your water butt to the pump.
- The outlet hose from the pump goes to the twin water valves.
- Each of the two watering zones can be set up in a number of ways; we recommend two 13mm LDPE distribution pipes around the perimeter of the greenhouse, secured with the provided clips.
- From these distribution hoses, you can run sprayers to cover a larger area (such as salads, seedlings) or drippers to feed water to the roots of larger plants (such as tomatoes, peppers, aubergines).
Control and sensor setup
- The control box is mounted in the greenhouse, and powered by a small solar panel, allowing you to run the system anywhere – including an allotment.
- Two soil moisture sensors are linked up to the control box, and are used to trigger (or prevent) watering for each zone.
- The electric water valves are wired to the control box, which decides how much to water, and when, based on soil moisture, heat, solar energy and timers.
How our polytunnel watering system works
The WaterMate kit is also suitable for polytunnel irrigation; no electricity or piped water is needed, just somewhere to mount a solar panel, and a nearby water butt.
The main difference when mounting WaterMate into a polytunnel is the frame fixings. We don’t provide fittings for polytunnel tubes as they vary so much. However, the same concept of two distribution pipes around the perimiter applies. Many people run the 13mm LDPE pipe along the ground; however this does not support spraying. To spray an area of your polytunnel, you’ll need to rig up a pipe above the area to be sprayed.
Spray nozzles and misters
Any 4mm micro irrigation spray or mister nozzle will do – we recommend the Antelco 360 and 180 emitters pushed directly into the LDPE distribution pipe. The pump provided with the WaterMate kit will power up to 20 of the blue emitters (70 litres per hour) per zone. If you’re running your WaterMate from a garden hose, you’ll have more capacity.
Drippers and dribblers
Drippers are great for getting water just to the roots of your plants. There’s a huge range available. We recommend ones that are adjustable, so that once you have set up your spiders web of drippers, you don’t have to rebuild when you change your plants, you just turn off the ones you don’t need.
Soak hose / porous hose
The pump provided with WaterMate will provide enough pressure for a 15 metre soak hose or porous hose, which can be buried in the ground, or snaked around on the surface. The soak hose would use one of your two watering zones, leaving the other one for sprayers or drippers, or a different area of the greenhouse or polytunnel.