Watering Your Garden In Winter

One of the frequent questions we get asked is ‘Do you have to water your garden in the winter?’ so we thought we’d put together some hints and tips on watering your garden during the coldest season, together with explaining why watering requirements change during the winter months. Firstly, let’s answer the most pressing question:

Do you have to water your garden in the winter?

You would think that with typical winters in the UK consisting of cool, damp and windy weather conditions that you wouldn’t need to water your plants in winter, but this isn’t the case. With winter covering from 21st December until the 20th March there will be some dry spells and this means that although you won’t need to water as frequently during winter as you would the rest of the year, there will be times when you will need to water your garden in winter. 

Why do you have to water garden plants in winter?

Although most of your plants will be dormant, or in a slow-growth stage, during the winter months when there are long dry spells you will still need to water them to prevent them from drying out. The plants which you should consider watering during these times are conifers and evergreens, together with any recently planted shrubs and container plants. 

Why do you need to water conifers during winter?

You may need to water your conifers during the winter months when there are dry spells as their needles will continue to transpire even during the colder months of the year. This means that they will need to be able to replace the moisture they lose through their needles by taking up fresh moisture via their roots. If they can’t do this because the ground is frozen or there simply isn’t moisture available as it’s been dry for a long time, then the needles will dry out, turning brown, damaged by a so-called ‘frost drought’.

To help stop this happening, you can take preventative measures in the autumn, including giving them a deep water in late autumn which ensures their roots are well hydrated before winter starts. In addition, applying a thick 5 to 10 cm deep layer of mulch around the base of the conifers (leaving a free space around the trucks) will help hold the moisture in the ground as well as insulate the roots from freezing.

If there are long dry spells during the winter months then check the soil around your conifers and if it appears dry deep down near the roots then you will need to give them some water. Only water on mild, frost free days and when temperatures are above 4 degrees celsius. Ideally water in the morning so the soil has time to absorb the water and so do the roots. Water the soil, avoid getting water on the foliage or trunk and water deeply - you want to provide sufficient water that it soaks down to the root ball so this is likely to take you watering for about ten minutes using a watering can or slow trickle from a hosepipe. If you are using a watering can then use tepid / lukewarm water to avoid shocking the roots.

How do you water evergreens in your garden in winter?

During dry, windy days in winter any broadleaf evergreens in your garden borders, such as boxwood, holly, rhododendrons etc will be susceptible to dehydration due to their larger leaves continuing to lose moisture. This can be made even worse when there are freezing temperatures and the ground freezes, preventing their roots from accessing the water they need.

Whilst observing these weather conditions may alert you that it’s time to water, you should always check the soil to see how dry it is before watering. You need to check the moisture at a depth of between 5 and 8 cm, so ideally push a trowel into the ground, and if the soil feels dry and crumbly at that depth, it’s time to water.

You don’t have to water your whole garden border when watering in winter, as you could be wasting water on many dormant plants that will be surviving with much less moisture, so use a watering can or hosepipe and direct the water to the plants that need it - in this case, your broadleaf evergreens. Always wait until the ground isn’t frozen and the temperature is above 4 degrees Celsius. Always water in the morning and water deeply, avoiding foliage and watering the soil around your evergreens so the water slowly soaks into the ground to reach the roots prior to evening when temperatures could fall and freeze the ground overnight.

Why do recently planted shrubs need watering during winter?

With autumn being the perfect time to plant new shrubs such as viburnums, euonymus and pyracantha, when it comes to winter, these new additions won’t have managed to grow extensive root systems, which would help them to access water from low down in the ground. This means that during dry spells, you may need to water them to ensure their underdeveloped roots still get the water they need.

Watering deeply and infrequently will help your newly planted shrubs to become established and encourage deeper roots to grow. However, when you are planting new shrubs in autumn, it’s best to apply a thick layer of mulch around them as this will help to retain moisture and reduce weed growth - you don’t want weeds in your garden borders even in winter as they will simply compete for any moisture available and may extract it from the soil before your plants have a chance.

What about my plants in containers?

How often should I water container plants in winter? One of our key tips when watering your container plants is to water sparingly - although you want to provide sufficient water that it reaches the roots of the plants, what you don’t want to do is over-water as water drains more slowly in winter so is likely to freeze before it has a chance to drain out of the holes in the base of your container. So only water when the top few inches of compost in the container feels dry. In the winter months this normally means watering every three to four weeks, although this could be more frequent if your container holds evergreens as these will still be transpiring throughout winter so will need to replace this moisture.

You should only water containers when the temperature is above 4 degrees celsius, as when temperature is lower the roots can’t absorb the water you are providing. So rather than the roots taking up the water it will freeze, which can damage the roots and potentially damage the container as it freezes and expands as it could crack your container.

Don’t always think that if there has been rain, that you don’t need to water container plants. Rain doesn’t always soak deep into the compost in containers, especially in winter when you are likely to have moved them to a sheltered position, which could prevent rain from reaching them. Also, if you have evergreens in the containers, their foliage could block most of the rain reaching the compost. In addition, if there have only been short showers then the rain might only moisten the surface of the compost, whereas there needs to be sufficient moisture to reach the roots of the plants. So the best plan of action is to check the moisture in the compost in your containers by simply inserting a finger knuckle deep - if the compost feels dry it’s time to water.

When watering container plants in the winter months, it’s important to water early in the day as this allows any excess water to evaporate before the temperature falls later in the day to prevent the water from freezing overnight. Although in the summer you might have set up drip watering systems to make watering easy and efficient, in winter you will have removed these systems to protect them from freezing temperatures so you are best to use a watering can, removing the rose so you can easily direct delivery of the water straight to the compost and avoid getting it on plant foliage.

If you have rainwater collected in water butts this is the best water to use as it should be at a similar temperature to the compost in the pot, so there is less chance of shocking the roots then using very cold tap water could. Rainwater is also free of the chemicals and salts which tap water can contain and which can easily build up in the limited amount of compost in a container.

It’s important when watering container plants that they have adequate drainage - what you want to avoid is water pooling at the base of the pot as it could freeze and damage both your plants and your pots. This means ensuring your containers have adequate drainage holes - if there aren’t many you can always add more by carefully using a drill.

It’s also really important that you elevate your containers off the ground - this not only ensures any excess water can drain away, in winter it’s also important as it improves air circulation and prevents pots from freezing to the ground. You can also improve drainage for your plants by mixing in perlite, vermiculite or grit into the compost - these all help to create more air pockets in the compost, preventing it from compacting and allowing water to freely drain through.

Helping Your Garden Stay Healthy Through Winter

We hope that the guidance we have provided will help you to water your garden plants during the winter to ensure your plants survive and remain healthy, ready to start growing vigorously in spring. Please remember, this post has been created using personal knowledge, insights from conversations with other gardeners and manufacturers in the gardening industry, and by drawing on information from gardening magazines, books, and online resources. We aim to be as informative and accurate as possible—but if you spot a mistake, please remember we’re only human!