The Simple Guide to Greenhouse Irrigation

Your greenhouse or polytunnel is like a warm, glassy haven for your plants. A spa retreat for seedlings. But what your greenhouse can’t do is water the plants for you.

That’s why you need a smart, efficient greenhouse watering system. Whether you’re growing tomatoes, coaxing cucumbers to climb, or just pottering about with a few herbs, watering is your number one job. It's important to get the correct amount of water spot-on, especially when some plants can suffer or even die from overwatering.

We’re digging into the best watering systems out there and how to match them to your plants, your lifestyle, and your greenhouse dreams.

What Watering Methods Are Available?

There are a wide range of systems that can be used in a greenhouse or polytunnel, including:

• Sprinklers/overhead spray
• Automated irrigation
• Solar powered irrigation
• Misting and spray
• Micro-drop/dripping/seep hose watering

Each of these methods of irrigation has its own set of advantages and disadvantages, these will certainly influence the method you decide to use.

What Watering System Is Right for My Greenhouse?

Every greenhouse will require a watering system, but the type and size required can depend on a few factors including the size of your greenhouse, the number of plants and the type of plants you’re growing. We have put together a guide below that details some of the features of each system.

1. Drip Irrigation Systems

Picture it like a miniature sprinkler system for your plants. Drip systems slowly release water directly to the roots where it’s needed most. They’re great for flower beds, vegetable patches and other contained areas. They can release water at set intervals throughout the day which minimises water waste from the run off of heavy watering.

These systems require water pressure, so are often combined with a solar powered pump from a water butt and can be completely automated. They’re useful for greenhouses of any size, as they can be scaled perfectly up or down.

Best for: Any size greenhouse; ideal for tomatoes, cucumbers, and thirsty veggies

2. Sprinkler Systems

If you’ve got a commercial-sized greenhouse or you’re growing foliage-heavy plants, a sprinkler system might be the solution. They raise the moisture levels of unplanted areas, making them great for preparing the unused sections of your greenhouse for planting.

Best for: Large greenhouses, plants that don’t mind wet leaves (like ferns or salad crops)

3. Capillary Matting, or Mat Irrigation

Seed capillary mats (also called self-watering trays) are one of the most effective, quick and low maintenance methods of keeping plants hydrated. The mats work by absorbing water, often from a reservoir which makes the mats wet. The plants are then placed on this and have access to water as and when they need it. This also forces plants to grow deeper roots, as their source of water is from below them.

Capillary matting also creates a humid atmosphere, which promotes some plant growth and saves water. As long as there is water in your reservoir, all of the plants under the mat will stay hydrated. Topping up reservoirs is normally done weekly, making this one of the lowest maintenance options available which makes it perfect for amateur growers.

Best for: Beginners, herbs, seedlings, and small greenhouses

4. Misting Systems

Along with sprinklers these are the best choice for a greenhouse with a lot of seeds that require regular watering. Misting systems spray a very fine amount of water onto the soil which gradually hydrates and moistens it without disturbing it. These are also often automatic, making the process of watering all of your seedlings seem effortless.

Best for: Big greenhouses and for propagating seedlings

Common Extras for Irrigation Systems

Automatic Watering Systems (with timers & controllers)

Think of this as cruise control for your greenhouse! These systems are completely automated, so you don't have to turn anything on or off. They work on a timer and provide your plants with the same amount of water every so often, depending on your requirements. This lends itself well to large projects, where manual watering may be too time-consuming.

Solar powered irrigation systems:

Solar powered irrigation systems are the eco-friendly future of gardening and they require no water, mains or electricity supply. This makes them completely self-sufficient and perfect for your smaller greenhouses. They are often in the form of drip irrigation, connected to a water butt (or any other non-pressurised water source) that sucks through water at regular intervals throughout the day.

Summary

Picking the right watering system for your greenhouse is key and there is always a solution out there that will suit your needs. Be realistic about the size of your greenhouse, the plants you can grow and how much you can afford to invest into an irrigation system and you will end up with a successful crop year on year.

We offer a range of hand-built Victorian design timber greenhouses, all finished to exceptionally high standards. These traditional and aesthetically striking timber buildings can be tailored to the size you need and finished in a wide range of luxury Farrow & Ball paint colours. 

If you are looking for a storage space for your tools and equipment, then our wider range of Garden Sheds may be the option for you. For a heavier duty shed, with more customisation options, you should consider our Superior Shed.

If you are unsure about what works best for you, whether it be for a greenhouse or one of our range of Garden Buildings, the best thing for you to do is speak to a member of the team. For instance, if you were to visit one of our UK Show Centres, you would be able to not only get first-hand guidance from the team, you would also be able to see our full custom collection. 

Alternatively, if you would prefer to discuss your requirements with someone directly, please contact us and one of our team will be more than happy to talk through the options available.