New and old landscapes alike are in need of watering right now…we just have not had sufficient precipitation to make a difference.  But how do you know how much you need to give them?

The genral  rule of thumb for watering is 1″ per week for lawns.  Now that doesn’t mean you just dump an inch of water on the lawn and call it good- that means that you let “rain fall” until it collects about an inch of water slowly allowing it soak in. Soaking in is a huge part of the process.  Also if you are not being consistant in your watering and go out and just water an inch  it is not being as beneficial as you will need to re hydrate more of the soil itself and the moisture doesnt have the chance to reach as deep.  Consistent care is beneficial to both you and your plants.

So now your asking how does this apply to plants- well they have a deeper roots system (that is a good and desired thing!) and so we need to make sure that the moisture is going deeper to get to those roots.  Here are some average root depths (and do vary depending on individual plant species):

  • lawns: 1-3″
  • perennials:  about 12-18″
  • shrubs: about 24-36″
  • trees: feeding roots are genrally in top 36″

We need to water enough of the soil to get moisture to these roots that feed the plant, so if we are just getting the top portion of the soil wet we are really not providing the water the plants need.  New plants are both more challenging and yet easier to water than mature plants.- How is that you ask, well the young plants have a more shallow root system meaning that you can get the water there faster, but because they are new and the roots are shallow it means we need to be more consistent with our care, as the top portion of soil is what dries out the fastest.  The better we water our plants as they are young , as in consistent and deeply, the better they are as they are older when the roots reach deep into the soil where more moister can be maintained, allowing them to handle more fluctuations in surface moisture.  Mature plants benefit from consistent care as well and need more water, but usually not as frequently because of the larger deeper root system

I have a lot of clients tell me they are watering, the irrigation system that waters the lawn is taking care of it for them, but do you see that the needs of the lawn are very different from the needs of the plants?  You would need a separate irrigation zone to water the plants longer to get the proper coverage.  And to prevent the water all from sitting on the top you need to run it often as well (allowing the water to soak in, and giving you more water applied in total)*

Click here for some general watering advice for our average MN soil, with the rule of sandy soil you water longer and clay soil you water for shorter periods of time ( absorption rate is the key here!)

*- Please consult with your irrigation specialist for they system you have installed, as the heads and zones set up can greatly affect the needs of your watering.