Is lime safe to use on your lawn?
We are working with a landscaper to grade our yard and address the overall health of the lawn. We haven’t done anything to the lawn since we moved in six years ago and it has grown many mossy spots. The landscaper is recommending: lime, grass seeding and grub treatment. I try to be very mindful of the items and products we use at home to be conscious of the health of my family, wildlife and the environment.
Is lime non-toxic? Is it safe to use around children, our garden and for the environment? What should I look out for when selecting grass seed that is non-toxic? I am very unsure about pursuing the grub treatment because I am worried about being exposed to any chemicals.
Abi Griffith, Horticulture Community Education Assistant
Lots to consider here! Moss tends to grow in shady, moist, poorly drained areas and also can indicate nutrient deficiencies – I’m going to address the lime and the grub treatment first, but I highly recommend reading through the bulletins at the end of this email for a good overview on lawn maintenance in general!
Lime is used to treat soils that are too acidic (common in Maine, and the moss growing may indicate that). We would suggest you do a soil test first to determine if it is needed, and how much is actually needed (unless this has already been done). The soil test will also help pinpoint any other underlying problems, and determine if any other nutrients need to be addressed.
According to Virginia State University, calcitic and dolomitic lime are nontoxic to humans, wildlife and pets. However, because all types of lime dust can irritate the lungs, eyes and skin, you should wait until the application of lime has been incorporated into the soil before using your yard. Some people like to wait until after a good rain, allowing for the lime to dissolve into the ground. Go ahead and check with your landscaper on this as well.
About grub treatment – we wouldn’t recommend it unless you know there’s been a problem in the past. Here are links to a UMaine Cooperative Extension White Grub Fact Sheet and one from Cornell Extension, Grubs in Your Lawn (PDF) for reference. If grubs do need to be addressed, it depends on what they are recommending for treatment. Once you know the specific materials, you can look at the material safety data sheets, check with Pam Breyer at the Board of Pesticides Control, or call the National Pesticide Information Center. http://npic.orst.edu/
General Lawn Care Resources:
Read through the bulletin Establishing a Home Lawn in Maine. You will find specific grass seed recommendations here.
Also Steps to a Low-Input Healthy Lawn is a good reference.
Not to add more to your plate, but taking in your comments about wanting to be contentious about the health of your greater ecosystem, you could look into “lawn alternatives” for some areas of your landscape and think about other things you could grow, especially if shade and or poor drainage is an issue with the moss growth. Pollinator Friendly Lawn Alternatives is a nice article from the University of New Hampshire to start with.