Watering a native garden can be confusing. While native gardens are tailored to your site conditions and will not require extensive watering once established, your new baby plants do need help getting through their first few years. There are some general rules of thumb we’ll outline here, but bear in mind that every property is unique, and you will need to get to know your garden's needs by checking the soil moisture.
How often should I water?
For the first year, if the weather is between 60-70 degrees, water once a week. If the weather is between 70-80, water twice a week. If the weather is over 90, water two to three times a week.
In the second year, watering should still be on your mind, but how much you need to water will vary a lot depending on your soil and site conditions, as well as the weather. If you have sandy soil, especially in sun, you should water weekly throughout the growing season. If you have clay soil, you may only need to water in the hottest and driest periods.
What’s the best way to water?
The best way to water is directly to the roots, to provide a deep watering and to help prevent leaf scalding and mildew. Hand watering with a hose or drip irrigation is good. Like a dry sponge, dry soil takes a few minutes to start absorbing water. If the soil is very dry, sometimes it helps to make a few “passes” and water every plant two or three times in one session so that you know the water has percolated into the soil.
Trees and shrubs need more water than perennials and prefer a slow drip around the base for up to 45 minutes, once per week. It is OK to water with a sprinkler, but plants are more likely to develop powdery mildew if water remains on the leaves when the air is already humid. Sprinklers should always be used in early morning or, second best, in the evening, to avoid the sun-magnifying effect of water on leaves during the hottest part of the day.
The top 3-4 inches of soil need to dry out between waterings to promote root growth. You will need to adjust based on the actual site conditions—depending on your soil, sun levels, and weather.
Do I still need to water if it rains?
If the garden receives a good rain (the soil is moist at least an inch down), skip watering for that week. However, it is always a good idea to check the soil moisture with a finger or a soil moisture probe. If it hasn’t rained for a while, even a hard rain sometimes doesn’t penetrate deep into the ground.
Remember that plantings close to the eaves of the house or near walls will often remain dry after a storm, depending on the direction of the rain, and they may need watering despite rain.
Large trees can also affect the soil moisture. A thick tree canopy will shield the soil from all but the hardest rain, and a tree’s roots—especially trees with lots of surface roots, like maples—may suck up the majority of the water. A mature tree can absorb hundreds of gallons of water per day, creating the most dreaded of conditions: dry shade. These areas may need to be watered more deeply or more often than other parts of your yard.
Conversely, you may have wet spots in your yard where you rarely need to water, especially if you have clay soil. Confusingly, overwatering can cause exactly the same symptoms as underwatering, because most plants also wilt when they have no oxygen getting to their roots.
How climate change effects your watering schedule
Chicago weather is notoriously fickle, but you may have noticed that it has been crazier than usual in the last few years. One effect of climate change is intensifying weather patterns—heavier rain, longer droughts, winters that are warmer overall but with deeper freezes or later frosts, etc.
Spring and fall are often wet in Chicago. Of course if it rains every day for the months of April and May, you don’t need to water during that period. However, a common weather pattern we’ve been seeing is that on June 1st it stops raining completely. All the nice juicy leaves the plants just put out are very vulnerable to drying out, so you need to water more in those periods to help them acclimatize.
Conversely, sometimes we get a very dry spring like, the one in 2021. If we don’t get much rain in April and May, this is a critical period to water, especially in new gardens. Most Illinois natives have evolved to need more moisture in the spring even if they are otherwise quite drought tolerant.
Similarly, a “normal” Chicago fall is pretty rainy, but if you have a new garden, you should still think about watering it weekly through the end of November or even into December. While dormant plants need less water than growing plants, the soil should be evenly moist going into the freezing weather or your plants can get what is effectively “freezer burn.” This is true even if we get a cold snap or snow in October or early November, because it can get warm and dry again even if it freezes.
Understanding your garden’s needs
All of this advice seems complicated, but the reality in the ground is pretty simple. Is the soil moist at the tip of your finger if you stick it all the way into the ground? Then you don’t need to water. Is it dry all the way down? Time to get out the hose.
If you check the soil moisture and observe how your plants are doing, you will learn how often you need to water, and what areas need more or less of your attention. Getting this close to your garden will also help you appreciate its nuanced beauty even more!
Don't forget, we offer monthly stewardship, which we highly recommend in order to establish the new planting design. The service costs $60 per hour per trained crew member. Stewardship includes weeding, pruning and general clean up, as well as leaf mulching in the fall.