06/03/2026
April showers bring May flowers. However, a 2inch rain deficit in May is a tough start to the 2026 season for herbaceous and woody plants in southern Wisconsin. I know it seems like summer started a while ago. But it is only June 3rd! With that in mind, the Madison Area has been warmer and drier than average and, currently, there is no end in the forecast. So lets talk about watering your plants!
There is no straight forward answer to "How often should I water?" or "How much do I water?". Science shows that outdoor plants need about 1inch of rain water per week. But how does that equate to a hose or watering can? Short of conducting experiments or calibrating your hose, you have to get your hands dirty! Potting soil needs to be waterd more regularly. This can be daily or around twice per week depending on plant age. Dig down into the soil to check if it is dry.
If the top 4inches of soil is dry, then the plants need water. If the soil has some moisture, you can wait a bit longer before watering, as long as your plants look healthy. Allowing plants to dry out slightly helps promote root growth and defense compounds as plants look for moisture. However, excessive drought weakens plants and can kill some of them.
This is also important for mature trees (the ones that have been in the ground for 5-200years). Even though they may not show signs of drought as fast, they still need water right now. Larger trees and shrubs can take 2-6 years to show signs of stress from drought, construction, or other impacts. For mature trees and shrubs, water under the whole canopy, not just right by the trunk. Those roots can spread up to 3Xs as wide as the canopy! Younger trees and plants will need watering more frequently since their roots do not spread as far as mature plants.
How to water in order to keep the plants healthy and happy? The answer is deep and infrequent. This means water each area of your yard for a longer period of time to get the water 6inches or so deep into the soil. BUT only do it when the top 3-4inches dries out. This should hopefully only be every 7-10 days during the dry spells. This should work for your trees, shrubs, herbaceous plants and grass. If your beds or lawn are drying out fast, consider compost or shredded hardwood mulch to add organic matter. Organic matter improves the soil's ability to hold and utilize moisture better. It also creates a better environment for your plants to access resources.
Ideally water before noon or from 6-8 in the evening. Watering in the middle of a hot day will cause more water to evaporate than to soak into the soil. In addition, the plants are conserving what water they have during the heat and adding water at this time could trigger them to stop this process, resulting in more water loss. Evening watering should be done when the plants still have time to dry out in order to help minimize fungal diseases that will thrive at night time temperatures. In general, morning watering is the best when possible. I water at night and in the morning on the weekends and my plants are doing just fine.
If you need any additional guidance, please feel free to reach out and speak with our horticulturalists, lawn technicians or arborists. https://srbassett.com/contact
