Often I get asked how often to water plants after planting. There are many aspects and horticultural points to bring out about preparing your plants for a healthy root system. A combination of environmental elements will help your outdoor plant thrive, and water is one crucial component.  

Overwatering or not consistently watering is probably the leading reason why plants are stressed out or die. We have very heavy clay soil in Western North Carolina. If you have clay soil, your water may not be absorbing and quickly running over the surface during hard rains depending on the slope and drainage. In other areas, the land may be holding water. Let’s first look at the soil structure around watering.

Soil Composition Matters When Watering Plants

Soil composition is essential for plants to grow well. It’s the element they establish their roots and anchor into place. Additionally, plants need oxygen as much as water around their roots. All the cells transpire whether it’s in the leaf or the roots. If the soil’s air space is taken up with too much water, the plant won’t get oxygen. As a result, those tiny, root hairs that do all the water absorption for the plant can be damaged. Hence, they’ll start to rot and die. The plant consequently has no access to water as roots rot even though water is surrounding it. The plant is unable to absorb the water, so the plant looks like it’s wilting. Some people make the mistake of adding water to the soil without investigating the soil moisture. You can use a moisture meter or check by digging down close to the roots. If the roots are slushy wet or drainage is poor, the plant has received too much water. Some plants have the physiology to deal with a damp situation. But for most plants, you have to find that happy blend, which is a mixture of moisture and air.

The ideal scenario is to strive for well-drained garden soil. If you’re working with clay soil, before planting, mix well into the plant hole ½ parts soil conditioner. This addition gives the soil structure rich humus and enough drainage. This soil composition will have sufficient air spaces around it for water and oxygen to filter through and reach the roots. The soil should contain enough organic matter and fine particles to keep a film of moisture around it between waterings. A balanced soil mix creates the ideal environment to grow most plants.

Watering Schedule for New Plantings

New plantings in the garden beds need moisture for the root balls to establish. The new plant’s roots need to be trained to reach deeper down into the soil. Inefficiently watering will keep the roots at the surface where the water evaporates faster. During hot spells or inadequate rainfall, this area dries out quicker and will stress the new plant. Even with precipitation, it might not be adequate depending on the tree cover, the slope of the surface, soil composition, and other plantings nearby. Shallow rooted plants especially need extra watering’s to get established and thrive. If other plants are nearby competing for the same moisture, one plant may not get enough. It’s imperative to keep a close eye on your garden plants when they’re getting acclimated. Plant the garden materials with water in the hole initially, and then water immediately afterward to hydrate the roots. After that, water your new plants deeply three times a week for six weeks. If you have an irrigation system, oversee it to ensure it reaches all the areas plants dwell. Most do not so supplement with additionally watering.

After the six week mark, water twice a week until the ground freezes. Startup with this regiment the following spring and follow it for the first year. Check the soil moisture levels if your plants are wilting or the leaves turn yellow or black prematurely. Adjust your water schedule accordingly. To measure, set a rain gauge in the garden in different areas to analyze weekly.

After your plants establish, generally, at the end of the second year, watering will need to be given weekly during weeks with inadequate rainfall. Remember that shallow-rooted plants use up the top six inches of moisture in the soil faster, so supplemental watering may be necessary for these areas. Always walk through your garden or sit and enjoy the scenery and make observations. Not only will your plants’ health depend on it, but it also gets you outside to enjoy all the nature around you.

How to Water Plants Deeply

When watering by hand without an irrigation system, use a wand with different stream indicators. Use the rain or shower setting to mimic natural rain. A jet stream is too harsh and will waste water and uncover weed seeds. The water will flow to fast and run off the ground, causing compaction and erosion. Using a faster stream of water will also cause runoff, which isn’t getting to the plant either. Hence why this shower setting will be slow enough for the water to absorb thoroughly into the ground.

Using sprinklers isn’t a good idea because it doesn’t efficiently get the water to the roots. Most of the water evaporates before it hits the plant. It is best for the plant to water around the drip line of the plant or its circumference. That way, you are sure to add moisture directly to the root system instead of just the leaves of the plant overhead.

Watering in the mornings are best to give leaves time to dry out during the day. When watering in the evenings after the sun sets, leaves may start showing signs of fungus or bacteria.

To ensure you are watering enough to establish a stable, healthy root system, check your soil moisture a couple of hours later. Dig down at least 6-12 inches to check the penetration of moisture. The soil should be moist like a wrung-out sponge. If the soil is dry, increase your watering regiment time. Likewise, if the water is sitting around the plant and water-logged, decrease your watering time. If you’re using an irrigation system, check the same way, and make adjustments in each zone.

How Much Water Do Plants Need?

How much water to give each plant depends on the size, type of plant, weather, temperatures, wind, and it’s water needs. Depending on the weather and hot temperatures, at various points throughout the year, make adjustments. The wind is often a factor in the winter and can desiccate a plant. Add more watering to adjust to these elements. 

For practical purposes, the following information is the average watering needs for new plantings. For instance, a tree needs more water to cover the broader area of roots versus a groundcover with a smaller root system. 

According to Water Use It Wisely, small plants need water to absorb to a depth of 10 inches. As a rule of thumb, an inch of rain will absorb to 1 foot providing there’s no runoff, and the rain is a steady soft shower. Consequently, that’s why supplemental watering is so vital to new shrubs. New shrub plantings need water down to 2 feet for their roots to establish. Likewise, larger plants and trees need water up to a depth of 3 feet. For instance, depending on the organic matter in your soil, give a new tree planting that is 5′ tall, 22 gallons of water. 

Measure Watering Time This Way

How long does it take to water a shrub? Find out by taking a 10-gallon bucket and using your water hose. Time how long it takes you to fill it up with the hose nozzle in the shower pattern selection. Record and use this time as a gage when watering. Most new shrub plantings start in the ground at a 2′ or 3′ height. Apply 4 gallons to a 2′ shrub and 8 gallons to a 3′ bush. As a rule of thumb, add 3-4 gallons to each foot of shrub height. After watering your plants around the root zone or drip line, wait a couple of hours. Then investigate how deep the water has filtered into the soil. You can dig down or use a soil probe. Remember to add mother nature’s contribution to the watering calculations and adjust supplemental waterings weekly. 

If using drip emitters, you will want to use several watering emitters around the drip line of the plant to get an even distribution of moisture. So, if your 3′ shrub needs 8 gallons, you could use four 2.0 GPH spot watering emitters around the drip line surrounding the plants. As the shrub grows, you can add more emitters to accommodate water needs. Be sure to adjust your timer to supply an adequate amount of water for your plantings. As your plants grow or weather changes, make adjustments as needed.

As you can see, there is a lot of science behind watering. And your conditions are ever-changing as mother nature has her preference to change things up like a science project! I must say, using good common sense and observing the health of your plants, the conditions they’re under and moisture levels of the soil come into play and are ultimately the responsibility of every homeowner. These are just average guidelines to go by to get your new plantings off to a good start. Feel free to adjust according to your natural elements and your plant’s needs.

Contact a Local Landscape Designer Today

If you have just put in a new landscape, then print this article and keep it handy for reference. If you’d like to get more integrated into gardening and would like a landscape design plan for your home, contact me today and let’s get started! And for all the rest of you, happy watering!