Container gardening allows everyone to grow their own food, regardless of their space and resources. It’s convenient because containers are compact and can easily be moved as seasons and needs change. They also allow you to have more control over pests, diseases, and weeds that plague traditional gardens.
However, keeping container plants properly watered presents a unique challenge to many gardeners.
Unlike plants grown in the ground, plants grown in containers have a restricted root system. They are not able to extend deep into the earth to look for moisture like they usually would during dry periods.
Containers will also dry out more quickly than ground soil. Potting soil is typically lighter and less compact than garden soil, so the moisture evaporates more quickly.
We can’t leave our plants sitting in water either. Overly wet soil causes roots to rot and invites pests and diseases.
So how do we master watering potted plants and still enjoy harvests like those gardening traditionally?
First, let’s take a look at some watering basics:
How Often Should You Water Plants?
The key to healthy plants is a healthy root system. Healthy root systems aren’t developed through daily watering.
I know, I know, it’s crazy to think about it, but bear with me.
Remember when I mentioned that plants naturally reach for moisture in the soil? The deeper a plant needs to reach for moisture, the deeper their root system goes. They don’t need to reach if we’re watering them daily.
Most plants do best if they dry out slightly between waterings. The soil on the top of the container may appear dry, but it’s still moist below the surface.
Test the moisture level below the surface by sticking your finger about an inch deep into the soil. If it still feels moist, your plant doesn’t need to be watered.
If you’re looking for something a little more scientific, you can also use a moisture sensor to help monitor your soil. The meter has a long probe that can determine moisture levels deep in your soil, allowing you to more accurately determine when your plants need to be watered.
You can gauge how often you need to water your plants by doing the soil moisture test each day after you water. Typically, you’ll need to water every two to three days.
Some plants will require a greater amount of water than others. Smaller containers will also dry out more quickly than large containers.
Looking for inspiration for your container garden? Check out: The 10 Best Planters for Your Container Garden
How Much Should You Water Your Garden?
We want to encourage deep roots by making water available all the way in the bottom of our containers. A good rule of thumb is to watch for water draining from the base of the container; however, some materials in potting soil (like peat moss) do not readily absorb water after they’ve been allowed to dry out. This leads to a lot of water runoff initially.
Adjust for dry soil by going back to each container and watering again after it’s had an opportunity to absorb the water from the first watering. Do the soil moisture test again if you think the soil is having a difficult time absorbing water. It may need to sit in a pan of water for a few minutes until it’s soaked up everything it needs. Do not leave the plant sitting in water long term.
Best Time to Water Plants
We want our plants to utilize as much water as possible, without wasting water they don’t need. In addition to only watering when our plants need it, we want to do what we can to avoid water evaporation.
Most water is evaporated during the heat of the day, so this is the absolute worst time to water our plants. Water droplets on the leaves will also increase the chance of plants being burned by the sun.
Evening hours are cooler, but water on the leaves overnight increases the chance of fungal issues developing.
Early morning hours are generally considered the best time to water your plants. The temperatures are cool, which reduces evaporation. It also ensures the soil is moist through the heat of the day, when plants will need it the most.
Automatic Plant Watering Systems
It’s great to say that plants should only be watered when they need it and only during certain times of day, but most of us have lives that don’t revolve around watering our plants.
And occasionally, we might even take a vacation. At the very least, we like the idea that we could someday take a vacation. We don’t want to have to worry about finding someone to water our plants when we’re away from home.
Automatic watering has been a lifesaver in my garden. Literally, it has saved the lives of thousands of plants.
It’s simple for a home gardener to set up their own automatic watering system. I rely upon an automatic hose timer so my plants can be watered deeply on a regular schedule.
Most Popular Automatic Watering Systems for Potted Plants:
Wick watering is an easy way to keep container plants watered, both indoor and outdoor. One end of a wick is placed in the container, while the other is placed in a water source. The wick is made from absorbent material that draws water from the reservoir to the soil when the soil becomes dry.
Wick watering can be used if you have multiple containers in close proximity. Wicks from each pot can be designed to share a common water supply.
Low cost wicking systems can also be made by recycling 2-liter plastic bottles.
The wick can be placed in the container before you fill it with soil, or it can be added after it has been planted. You will want to make sure the wick is wet before it is placed in the container so it will properly transfer water to the roots of your plant.
I recommend placing your wick deep in the soil to encourage deep root development.
Bottle watering uses a water reservoir, capillary action, and gravity to slowly feed water to the soil. Watering globes are available commercially, but the same effect can be accomplished with glass or plastic bottles.
Similar to wick watering, bottle watering will slowly draw water down into the soil as your plant needs moisture. Bottles with tapered ends work best for this, like soda or wine bottles. Fill your bottle with water, and invert it into the soil near the base of your plant. Check the water level in your bottle and refill it as needed.
I prefer to use recycled wine bottles for bottle watering due to their long, tapered necks. The long necks can reach deep into the soil and provide stability to keep the bottle upright.
If you decide to use a recycled plastic bottle, you may want to get a bottle spike. The bottle spike will provide additional stability, as well as restricting the opening of the bottle to keep all the water from pouring out before being placed in the soil.
Drip watering systems run lines with small holes that deposit water directly at the base of the plant. They connect directly into your garden spigot and are run for a certain length of time to ensure all plants meet their watering needs.
Since the water is deposited slowly, the soil has time to absorb most of the moisture without much water runoff. You will need to experiment with the length of time you leave the water turned on. Your goal is to have some water running out of the bottom of the container so you know that the deepest roots have gotten what they need.
Once you have determined how long to run the drip irrigation, you will need to check the moisture levels in your containers daily. If they dry out in two days, then you’ll need to run irrigation every two days, etc.
Group your containers together based upon their watering needs. Larger containers will need to be watered for a longer time, but will need watering less frequently. Smaller containers will need less time more frequently. You will also find some of your plants use more water than others.
Containers with similar watering needs should be grouped together into their own “zone.” A zone is one individual line of your irrigation system. Each line will have its own unique duration and frequency for watering.
It is easy to set your drip irrigation on an automatic timer. The timer will allow you to program your irrigation needs to run at a specific time at the interval that you choose. You won’t need to worry about having time to water early in the morning or having someone water while you’re on vacation because an automatic drip will keep your plants hydrated on schedule.
Micro sprayers are similar to drip irrigation, except that tiny sprinklers are installed along the line. The sprayers distribute a fan of water across the base of the plant, covering a wider area of the container than a drip would.
Micro sprayers distribute more water in a shorter period than drip irrigation, but still at a rate that the soil can easily absorb the moisture.
Determine the duration and frequency of your watering for micro sprayers like how you would for drip irrigation. You’ll find the duration will be shorter since more water is being distributed, but frequency should stay close to the same.
Kits are available that make installing drip irrigation and micro sprayers easy. Once you have the initial setup, you can add lines and customize your setup to best meet your needs.
Keeping your container vegetable garden properly watered doesn’t need to be complicated or time-consuming. With a little planning, you can enjoy your own homegrown vegetables and still have a life outside of the garden.
How do you keep your garden watered? Comment below with your favorite method.