I have boots, a warm jacket, a scarf, long pants, and gloves; it's time to head outside and water!
Wait...what? Water when it gets cold? Isn't the moisture in the air good enough this time of year? Is it even good for the roots to water in the cool season; won't they freeze if the soil temperature drops too low?
Those are all valid questions. Let's get to the bottom of them.
What We Can Learn From Making Mud Pies
When I was a child, making mud pies was a passion to the point of selling them to other neighborhood kids. The concept was easy enough with the right combination of ingredients: dirt, water, and hands capable of massaging to form the pie. From there, you just needed to add a little aesthetic magic—adding contrast by utilizing different soils taken from the yard. Some stuck together, others easily flaked, while others just fell apart (and I have to admit some of them were even tasty).
This concept fascinated me to the point that when I got into college, I took classes called "Soils" to gain an in-depth understanding of how soils work. When I found out there was a delicate symbiotic relationship between soils, roots, and water, a new door to a world of Things Green was held open for me. It still excites me to this day.
Let's explore how to keep plant roots alive in all types of soil as the weather turns cooler.
Seasonal Watering For Plants
We have a natural instinct to water in spring through the end of the summer. The new leaves forming on plants, some of which may bud into flowers that scent the air, followed by fruit, nuts, or seeds, all act as reminders to provide hydration to our plants. In fact, if we forget to water during those seasons, the plants will speak to you, screaming for water with drooping leaves and dry, cracked soil.
But what about when the weather starts to change? A deciduous plant will begin its process to go into slumber by losing its leaves. In turn, many folks stop watering. Should they, though? Au contraire, we need to be attentive to our plants' hydration needs all year because they will absolutely suffer if we don't.
What Do Root Hairs Have To Do With Watering Plants
To the naked eye, roots are just that - roots. But, if we look under magnification, we would see roots are protected by root hairs. When these root hairs dry out, they expose the root to an uncomfortable environment which forces them to stop growing. In turn, they may dry up and die!
It takes around 6 weeks for a root to rebound from such a tragedy when conditions become favorable for the root hairs to start growing again. If your soil has the proper amount of moisture, the root hairs will stay alive to protect the root for dormant plants and evergreens alike.
Cooler weather always slows down plant growth above the ground. However, soil temperatures are always warmer than air temperatures, which means we have to cater to the needs of the soil and plant roots by properly watering. But first, we need to look at what type of soil you actually have.
How Soil-Type Can Impact Plant Watering Needs
When I was in college, my senior project was to measure soil consistency. I selected a mission because they were on a hill that once had an orchard, kitchen garden, stables, and good old-fashioned hard dirt. I took soil samples 12 inches down every 12 inches apart for 1200 feet. Sometimes the probe easily took the sample, while other times we had to drill the soil sample out.
This exercise helped me understand that soil structure can change foot-by-foot, and when I'd get calls on my radio show from Maine to Florida and from Texas to California, this helped me understand how to help my callers' plants out.
Types of Soil:
Soil changes depending on where you live. Not to get too garden geeky, but soil structure has several components that can be measured either in a laboratory or by conducting a home test. Personally, I'd call my local county extension office as they might do the test for you or provide a recommendation.
Regardless, they'll get percentages of what is in your soil and measure it against a soil triangle, which is triangulated to get one of the following types of soil:
- Clay,
- Sandy Clay
- Silty Clay
- Sandy Clay Loam
- Clay Loam
- Silty Clay
- Loam
- Sand
- Loamy Sand
- Sandy Loam
- Loam Silt
They will also measure the amount of organic matter (OM) you have. In a perfect world, you'd have 48% soil particles (sand, silt, clay) with 2% OM that would be large enough to accommodate 25% air space and 25% water. The goal is to get your soil as close to those numbers as possible. A soil's report from the lab will usually recommend how to do that.
How Deep Watering Can Prevent Roots From Freezing
Did you know you can tell the size of a root ball without digging the plant up? Technically, a root ball can be measured by the size of the plant canopy. If your apple tree canopy is 8 feet wide by 6 feet tall (minus the trunk), that's the size of the root system supplying life to that tree.
One of the worst things to do to all plants is surface irrigate. When roots come to the surface, it usually means they are searching for water. If you live in Chicago, chances are it gets 32º or lower, which means your soil can freeze upwards of 3 to 4 inches very quickly. How does this help roots if they are at the surface? It won't! Roots will freeze, the root hairs die, and so can the plant.
Before we get to that tragic moment of no return, it is best to rethink the way you water, getting moisture down past that 3 to 4-inch zone with subsurface irrigation that can direct water to more than 20 inches down where frost can't go, and the soil is warmer to hug those root hairs, which protect roots. Plus, the roots won't have to reach up for their hydration, so they will no longer be in jeopardy of freezing.
When capillary action kicks in, plants thrive with subsurface irrigation. You won't see growth on top of the plant right away, but when it warms up, you'd better stand back—you might get poked in the eye because you've given those roots an energy shot to take off and grow!
Now, don't get sassy if your soil doesn't freeze. Those of us who only get a mere frost can also have problems that'll send a plant into rigor mortis even quicker. Killer frost can settle on soil where surface roots are. Even those of us that live in the milder areas like New Mexico, Arizona, southern California, and Nevada, will need to keep soil alive by encouraging the soil food web. Good fungi and bacteria, worms, protozoa, nematodes, and other beneficial beasties to do what they do best when we provide proper watering.
How Much Should You Water In The Fall and Winter?
Regardless of your soil profile, it must be kept moist, not wet. Think of a sponge that has been rung out. The amount of moisture that's in that sponge is comparable to the moisture level your soil should be kept at.