Should You Turn Off Your Automatic Watering System for Winter?

At a Glance

Automatic watering systems do not always need to be switched off for winter. Reduce watering as plant growth slows, check soil moisture, and keep watering active crops as needed. Prepare exposed equipment for frost and gradually increase watering in spring. 

Purchase the Harvst WaterMate systems to manage your setup through changing seasons. You can also build your own system with Harvst more suited to your requirements.

Do Plants Really Need Watering All Winter?

You don’t always need to turn off your watering system for winter. Greenhouse plants, for instance, generally need less water as temperatures fall and growth slows, but winter crops and other growing plants may still need regular moisture. The key is to adjust your watering schedule to suit your plants and greenhouse conditions.

Shorter days, lower temperatures and reduced evaporation mean compost and soil can stay damp for longer. Continuing with your summer watering programme can leave roots sitting in wet growing media, increasing the risk of root damage.

If you are deciding when to stop watering greenhouse plants, check the moisture around the roots before changing your schedule. Dormant plants need very little water, while winter salad, herbs and other crops can still need occasional watering.

What Happens If You Leave Your System Running?

An automatic watering system can keep delivering water even when plants need less. If the schedule stays unchanged throughout winter, the growing medium can remain too wet between cycles.

Overwatering can damage roots, encourage root rot and waste water. Solar-powered systems may also have less energy available during shorter winter days, which can affect how long they can operate.

Review your watering schedule as autumn progresses. Reduce watering frequency or duration, and check the growing medium regularly. If different plants have different moisture needs, use separate watering zones, if available, to manage them independently.

Harvst’s WaterMate Temperature Sensing Helps

Harvst WaterMate, an automatic watering system, comes with built-in temperature sensing. These temperature sensors can help you adapt watering to changing conditions. The system can be configured to provide additional watering when temperatures are high and to stop pumping when freezing conditions are detected.

This helps you respond to temperature changes without relying on a fixed summer schedule. You still need to check plant moisture, since temperature alone doesn’t determine when each plant needs water.

How Freeze Protection Works While Your System Is Idle

Freezing temperatures can damage exposed irrigation pipes, fittings, pumps and water supplies. Before winter frost arrives, follow the Harvst WaterMate guide to winter care and frost protection to decommission your equipment. Depending on your setup, this may involve draining exposed components or disconnecting parts that should not remain full of water.

WaterMate’s temperature sensing can be configured to stop pumping when freezing conditions are detected. However, this does not make exposed pipes, fittings or water containers frost-proof. The equipment still needs suitable winter preparation.

If you plan to leave your system idle for an extended period, check the water supply arrangement, inspect the pump seal, clear any water traps and verify that battery levels or solar connections are secure before shutting down.

When It’s Time To Scale Back or Pause Watering 

There is no universal date for switching off an automatic watering system. Knowing when to stop watering plants in the UK depends on the crops you grow, the temperature of your growing space and how quickly the growing medium dries out.

Use these signs to guide your decision:

1. Reduce watering when growth slows and compost takes longer to dry.
2. Continue occasional watering when winter crops are actively growing and the root zone needs moisture.
3. Pause scheduled watering when plants are dormant and the growing medium remains damp between checks.
4. Review individual zones if some plants need water while others can go longer without it.

When watering the greenhouse in autumn, start by reducing your summer schedule instead of switching the whole system off automatically. Check the soil or compost before making further adjustments. 

At the same time, as you scale back or pause watering for winter, different plants may need different adjustments. Separate watering zones let you reduce watering in one area while still supplying moisture to actively growing plants. 

The WaterMate Mini offers this flexibility for smaller growing spaces, with coverage up to 6 m². It supports up to 40 plants using drippers or 12 sprayers, with two independently managed watering zones. Power options include a 10W solar panel, with a 240V mains-powered version also available. 

WaterMate Mini can draw water from a water butt using its pump setup and adjust each zone as plant growth slows during winter. If you rely on an outdoor water butt, insulate or drain exposed feed pipes, as standing water in the supply line or container can freeze solid in sub-zero spells. 

For off-grid allotment growers or remote plots without local Wi-Fi, Harvst also offers a 4G-connected WaterMate model that lets you monitor and adjust schedules from your phone throughout the winter.

Restarting Your System Come Spring

As temperatures rise and plants resume active growth, you can gradually increase watering to match their needs.

Before restarting your automatic watering system, inspect pipes, connectors, valves and drippers for damage and blockage. Clean the filter if your setup includes one, check the water supply and run a short test cycle to confirm each zone works correctly.

Start with shorter watering cycles, then increase them as plants grow and the growing medium dries faster. If you grow several types of plants, remember that they may not all need the same increase in watering. Separate zones let you adjust schedules for different growing areas as spring growth picks up. This is also the ideal time to evaluate whether your current setup matches the evolving scale of your growing space.

For larger greenhouses and polytunnels, Harvst WaterMate Pro supports up to 20 m² per zone and can be expanded to six zones with additional zone kits. It also supports up to 120 individual plants using drippers, has a 35 psi pump compatible with a suitable soaker and porous hose, and is available in solar- and mains-powered versions.

A Simple Autumn Watering Decision Guide

Use this guide to decide whether to continue, reduce or pause automatic watering as the weather cools.

You don’t need to turn off every automatic watering system for the entire winter. Adjust the schedule to match plant growth, check moisture levels and prepare exposed equipment for freezing conditions.

Choose a Watering System for Year-Round Growing

Still wondering when to stop watering greenhouse plants? Managing greenhouse or other growing-space irrigation through winter and into spring is easier when your setup suits your space and the plants you grow. 

Harvst WaterMate systems offer different coverage and zoning options, helping you manage watering across smaller greenhouses and larger polytunnels.

Compare the Harvst WaterMate systems to find an option that suits your greenhouse size, watering zones and seasonal requirements or build your own WaterMate setup. 

Product specifications and features are subject to ongoing improvement. For the latest details, please see individual product listings.