Pine trees are a beauty in any landscape and any season. They’re also evergreens, which means you can count on some natural color year round, whether you’re in the height of summer or the peak of winter. While they’re known for being fairly hardy trees, pine trees still need some special care, especially in the seasons they tend to be neglected the most.
Pine trees need some kind of watering year-round, even in the winter. However, it’s not always appropriate to water them every single winter day. Make sure the air temperature is at least 40 to 50°F, and that you water from the trunk of the tree to the area covered by the branches.
Of course, there are plenty of circumstances in which you should avoid watering pine trees in winter. And, there are just as many reasons to find the right conditions and take the time to water it throughout the winter.
Why You Should (Or Shouldn’t) Water Your Pine Tree In The Winter
Far too many people make the mistake of thinking that because they are evergreen the trees will essentially take care of themselves. Now, there’s a reason people think that: evergreens are known to be fairly easy to care for.
However, like any other living organism, pine trees still need a little oversight, some
maintenance, and the proper resources to grow.
Think of evergreens also as ever-growing. They aren’t plants that go dormant for months at a time until you’re ready to plant them again in spring. That means that, unlike plants that go dormant over the winter, they still need the resources to maintain their health.
But there are some times during the winter months when pine trees shouldn’t be watered. Some guidelines for reasons you shouldn’t water your pine during the winter are:
- Temperatures under 40°F
- Recent precipitation
- Snow cover
- A heavy frost expected during the day
It’s overall quite fascinating these green giants grow during the winter – you can take a peak at our article on how evergreens grow during winter if you’d like to learn about that. Otherwise, read on!
4 Reasons To Water Your Pine Tree During The Winter
1. Pine Trees Don’t Lose Their Leaves Like Other Trees
Deciduous trees lose their leaves in the colder seasons. Then, the leaves grow back as the weather warms.
As you might assume, pine trees don’t lose their leaves based on season, like deciduous trees (like maple trees) do. Because they don’t lose their leaves, (or in this case, needles) they still have to expend resources maintaining their foliage throughout the year.
Note: foliage is a term widely used to describe the ‘green’ parts of a plant, typically meaning stems, shoots, and most notably, leaves.
While trees that lose their leaves can more or less ‘hibernate,’ evergreens can’t. This means that your pine tree needs to be hydrated enough to keep its needles supplied with crucial resources.
2. Pine Trees Tend To Grow During The Winter Months
Unlike other trees, which lose their trees during the fall and winter, pine trees keep their needles throughout the year.
This allows them to take any bit of sunlight they get and convert it into energy to fuel their growth. Whenever any plant does this, it’s referred to as photosynthesis.
Because pine trees keep their needles, even in the winter months, they need some sources of sunlight and water. This is not only to maintain their leaves (needles) but also to use the sunlight gathered by those leaves to continue their growth.
Even though growth rates are slower in the colder months, the pine tree still needs the resources to balance the maintenance of leaves and new growth.
3. Watering Pine Trees In The Winter Can Keep The Soil Loose And Healthy
Most people think of soil as simply being the medium in which they grow their plants. However, far too few people take the time to consider the makeup of their soil (aside from fertilizing it and perhaps checking the pH levels).
Pine trees are like any other plant, they get the nutrients and water they need from the soil, but they also absorb some oxygen from it.
Very dry soil can become compacted, which means that aside from cracking on the very topside of it, there’s very little room for oxygen to move through. The roots of any plant need oxygen for healthy growth.
When soil becomes dry, water helps to loosen it up. As the soil loosens, there’s more ‘room for movement,’ so to speak. Essentially, that means that by watering your pine tree, you also loosen the soil. As a result, it allows more oxygen to move through the ground and reach the plants’ roots.
4. Watering Can Prepare Pines For Spring Growth
Most plants experience reduced growth throughout the winter, and pine trees are no exception. However, many evergreens spend much of the warmer months making up for growth and resources they went without during the winter.
By watering your pine tree during the winter, you’re helping it maintain its health during a tough season. Not only that, but you’re actually giving your pine tree a head start to begin better growth in spring.
Rather than seeking to make up for lost time and energy (i.e. repairing and replacing damaged or deprived needles), they can get started with optimal growth right away.
If your pine tree was newly planted in the Fall, take a look at our guide on what to expect with our full pine tree timeline overview!
How To Water Your Pine Tree During The Winter
So, you’ve decided that the right choice is to water your pine tree during the winter? You’ve verified that all the right conditions are in place? Great!
Now all you need to know is just how to water pine trees during the winter.
You may even have a regular irrigation system in place for the other three seasons. That’s wonderful, but chances are you’re not looking for burst pipes in the winter, and therefore likely don’t run it (And by the way, don’t risk burst pipes and water damage, just manually water your pine trees in winter).
Let’s review the pre-watering checklist again:
- Is the ambient air temperature at least 40 degrees Fahrenheit?
- Is there little chance of a hard frost within the next 12 hours?
- Is the ground free of snow cover?
If you can answer yes to these three questions, continue on. Otherwise, wait until your area does meet the conditions you read above.
Test The Soil For Moisture First
In many cases, this means you need to check the soil at a depth of at least four to six inches. Otherwise, the roots could already be saturated with moisture. By adding more water, you can actually cause more problems.
After you dig a very small hole to that depth, you can just feel for moisture with your fingers. The soil should be mostly dry or just a little damp before you begin watering.
Here’s a tip: it can be difficult to feel moisture accurately in cold weather. If you’re unsure, a moisture meter can let you know for sure. We recommend the SONKIR Meter– it measures soil moisture, pH level, and light exposure.
Find The Area You Need To Water
Watering pine trees in winter is more precise than it initially appears. In the spring and summer, you may be able to get away with watering the general area. Or, if you have an irrigation system, where to water your pine isn’t likely something you usually even think about.
But you want to keep the ‘watering area’ contained within a certain diameter. And it’s important to know that this area is completely dependent on your tree, and its size.
With that in mind, you should still start watering your tree around the base of the trunk. However, you still need to spread the water further, to ensure that the roots get equal moisture.
But where do you stop?
Water your pine tree in the area that starts from the base of the trunk and extends to the length of the lower branches. This area is often called the ‘dripline.’
Figure Out How Much Water To Give Your Pine Tree
While you’ll see many sources telling you to water the pines with 10 gallons of water for every inch it measures around (and yes, that is a lot of water), that rule doesn’t necessarily apply to watering in winter.
You do want to make sure you give your pine tree enough water. At the very least, you should make sure the moisture from the initial watering seeps at least a few inches deep (for a mature tree). For juvenile pine trees, saturating the soil by just one or two inches is usually sufficient.
A study from Forest Ecology and Management notes that the larger the pine tree is, the
deeper the watering needs to go to supply the roots.
The key is to go slow and check saturation as you go. In winter especially, it takes a little longer for water to seep down into the soil. It’s far better to take a little extra time and ensure that your tree is getting a proper balance of moisture and oxygen. Remember, while watering can help oxygenate the soil, too much water can drown the roots.
If you’re not experiencing much humidity or active precipitation, watering your pine trees once or twice a month during the winter should be sufficient.
Mulching Your Pine Tree During Winter
Mulching is a pretty familiar concept to regular gardeners. But, for the uninitiated, mulching is basically covering the soil around your plants or trees with a natural material, often including wood chips, grass clippings, straw, or fallen leaves.
If you’re concerned about your pine trees’ well-being in the winter, and you’re (clearly) doing your research, mulching is going to come up pretty frequently.
So, should you mulch your pine tree in the winter? Yes! Mulching insulates plants, helps moisture retention, and can even help fertilize them.
Mulch Helps Retain Moisture For Pine Trees
A lot of moisture that isn’t immediately used by plants evaporates through the soil as it dries out.
If you experience a lot of precipitation, such as in a rainy season, this isn’t necessary. However, in winter, even if you see snowfall, this isn’t moisture that’s really available for the deeper roots of your trees.
Using a mulch like FibreDust CoCo Mulch (which is designed for moisture retention) can make keeping your pine trees hydrated much easier.
It’s best to mulch your pines before the temperature really drops (to 40 degrees or below). This allows your soil to retain as much moisture as possible. As a result, it lowers the chances of your pine trees becoming dehydrated throughout the winter even when you can’t water them.
As a bonus, mulching can also help insulate the soil and maintain the temperature for longer.
Mulch Acts As A Fertilizer For Pines
If you thought mulch was only useful as an insulator or method of retaining moisture, just wait. Not only does mulching serve that purpose, but it does more than that.
Because the materials you use for mulching are organic (meaning they will go through natural processes of decomposition) they go back into the soil. How does that affect your pine trees?
It allows essential nutrients to release into the soil. This begins slowly when you add mulch around your pine trees, and amplifies as spring and summer arrive.
Fertilizing Your Pine Tree In The Winter
If you mulch your pine trees, there’s really no reason to fertilize them in the winter. The temptation to fertilize, when you water during the winter is strong. However, it’s not necessary!
A lot of people think that if they’re watering, they may as well do two things at once and fertilize. The problem is that your pine tree isn’t trying to grow significantly during the winter.
Sure, your pine tree might grow a bit during the winter. But this isn’t its main growing season. Your primary focus should only be on helping your pine tree maintain the best health possible for when spring and summer arrive.
In short, do not fertilize your pine trees in winter.
Wait Until Spring To Fertilize Your Pine Tree
The fact is, fertilizing during winter can do more harm than good.
You’re basically confusing your plants with the nutrients you give them. Fertilizing your pine tree in winter gives it a signal that it should put energy into producing new growth. There’s a reason new growth happens in spring.
Warmer temperatures and increased sunlight are ideal conditions for new growth. In cold temperatures with decreased sunlight, a pine tree’s resources are diverted to new growth that really has no chance of thriving.
Several studies, including a particularly notable study published in Nature Communications, show that while the temperature may play a contributing factor, increased sunlight (referred to as solar radiation) is the main indicator for boosting photosynthesis, and as a result, hastened growth.
Wait Until Spring To Fertilize Pine Trees
This gives new growth a chance to thrive and harden off, or acclimate to cooler temperatures before winter comes.
Hardening off is an important process and allows pine trees to absorb the proper amount of sunlight, without any abnormal decrease due to the change. A study published in Planta showed that without allowing new growth time to harden off, the ability of the pine (in the new needles and branches) to absorb sunlight is limited.
Here are some of the best soils for pine trees!
Should you water your pine tree in the winter? Yes! As long as there isn’t snow cover and it’s at least 40 degrees or warmer outside.
Other important points to remember before planting or watering your pine tree:
- Fertilize only in spring, not winter
- Mulching preserves moisture and humidity
- Adding mulch also helps fertilize pine trees
- Water pine trees slowly
- Distribute water evenly through the dripline area (from the trunk to where the lowest branches reach)
- Check the soil before you water
- A little water helps the tree and the soil, but too much can suffocate roots
Pine trees do have some growth during the winter. But more importantly, they have to maintain the needles they have. If they become dehydrated, they won’t have the resources available to keep their existing needles healthy. In turn, that means they have less foliage to gather sunlight and convert it into usable energy.
Bag, P., Chukhutsina, V., Zhang, Z., Paul, S., Ivanov, A. G., Shutova, T., … & Jansson, S. (2020). Direct energy transfer from photosystem II to photosystem I confers winter sustainability in Scots Pine. Nature Communications, 11(1), 1-13.
Kerhoulas, L. P., Kolb, T. E., & Koch, G. W. (2013). Tree size, stand density, and the source of water used across seasons by ponderosa pine in northern Arizona. Forest Ecology and Management, 289, 425-433.
Vogg, G., Heim, R., Hansen, J., Schäfer, C., & Beck, E. (1998). Frost hardening and photosynthetic performance of Scots pine (Pinus sylvestris L.) needles. I. Seasonal changes in the photosynthetic apparatus and its function. Planta, 204(2), 193-200.