I have one giant Emily Carr-worthy pine in my back yard. The lawn and borders nearby have been bombarded with falling needles in the past few very hot, dry summer months and the acidic soil is thinning the grass and cause some previously-happy iris and other flowering plants to grow less vigorously and bloom less profusely. I bought some pelletized lime for lawn and spread some in a patch of grass as an experiment but it did not seem to dissolve, just sat there over the course of that summer, clogging up the roots. Should I try again and allow it more time? And is it safe to scatter some in the flowering border? Thanks for any information about how long liming takes to be effective when you are unable to dig it into the soil.
Soil pH is very important as the acidity or alkalinity determines how well plants are able to absorb nutrients through their roots. Acidic soil would have a pH of 5 or lower, alkaline soil would have a pH of 9 or higher, and neutral soil would have a pH of around 7. The optimal range for most border plants is around 6.5 and for lawns it would be around 7.5. I would suggest, before adding any more of the lime you have purchased, that you do some soil testing as this will tell you what you’re dealing with.
Lime comes in two main forms – agricultural and dolomitic – the safest and easiest to work with is the agricultural form as it is finely crushed limestone and works into the soil well. Lime is not very water soluble so the finer the particles the easier it will dissolve and be available for use by the plant roots. Ideally, it should be worked/tilled into the soil to a depth of 6-8 inches the year prior to planting so that it can begin the soil pH change before any plants are added. Always wear protective eyewear and gloves when using any lime product and read and follow the package instructions carefully.
In your garden, I would suggest you rake up and discard all fallen pine needles on the lawn and in the border beds – do not put them in a home composter, include them with garden waste to send to your municipality.
After you’ve tested the soil in your border beds, depending on the results, you have two options – 1. Dig in the lime around your current plantings to try to raise the soil pH in the hopes that it may breathe new life into the plants or 2. Opt to begin replacing the struggling ones with more acidic loving plants. The first option will have you testing and digging lime in on an ongoing basis and the second option will, over time, change the plantings to “right plant, right place”.
With regards to your lawn, as previously stated, Lime is not very water soluble and in pelletized form, I’m not sure how much good it’s doing with regards to helping the grass roots absorb the nutrients they need. I would suggest you contact a lawn care company and have them assess the situation. It may be that de-thatching and a good aeration of the lawn will help the pellets penetrate into the soil rather than sitting on top of it.
Hope this helps.