Lavender ph - Ask Extension
I made three raised beds with a fifty-fifty mix of coarse sand and soil. I planted Lavender Phenominal. After planting I found out that Lavender needs...
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Lavender ph #866258
Asked April 29, 2024, 9:58 AM EDT
I made three raised beds with a fifty-fifty mix of coarse sand and soil. I planted Lavender Phenominal. After planting I found out that Lavender needs a ph between 6.5 to 8. I’ve tested soil in my area before and it came out in the 5.5 to 5.8 range. I have pellitized lime on hand for a food plot. Hard to tell how much to put on and how often.Would mulching this with limestone from the driveway do what I need over a long period of time. If not is there any home ph testing kit that would accurately test for ph. I have heard they are not very accurate. Not practical to send out three test kits every year.
Ashtabula County Ohio
Expert Response
Hi Michael,
Your photo indicates that your raised beds are not very large, so treating with lime to raise the pH in the soil there won't require a lot of material. However, mulching with limestone from your driveway may not work fast enough to do what you need. The speed with which lime can change soil pH is affected by the surface area of the lime particles you add and the amount of contact they have with the soil. Limestone chunks from your driveway would not have as much surface area as either pelletized lime or ag lime (which are smaller pieces), and would not have much contact with the soil. You would be relying only on erosion or leaching of those limestone chunks, which would be relatively slow.
The pelletized lime you have on hand is preferable. There is information on using this in the home garden in this article: https://www.canr.msu.edu/news/growing-lavender-in-michigan-advice-for-a-purple-garden. The basic recommendation given here is to start by applying 1/8 of a cup of lime per square foot on the soil surrounding the plants.
I do not know of any home pH tests that are reliable. However, if your beds were filled during the same year using the same sources of sand and soil, you may be able to get away with kit-testing one bed each year in rotation, or even one bed every two years. Information for one should be representative of all three, assuming that all are in simular environments. (Note, for example, that if one has leaves on it throughout the winter and the others do not; or one gets run-off from the house and others do not, then they may not remain similar over time.)
Since anything you can do to raise the pH in these beds will help your lavender, my suggesion would be to start with the application of lime described above for 2024. Then, consider sending in samples from one bed in 2025 (instructions can be found at https://ohioline.osu.edu/factsheet/hyg-1132) - if your pH is satisfactory, then don't treat in 2025, and if there is still a ways to go to raise the pH enough, then treat again next spring. I am hopeful that your lavender will be showing you it is happier throughout this season as well, with increased foliage growth and deeper green color.
Best of luck with those beds!
Your photo indicates that your raised beds are not very large, so treating with lime to raise the pH in the soil there won't require a lot of material. However, mulching with limestone from your driveway may not work fast enough to do what you need. The speed with which lime can change soil pH is affected by the surface area of the lime particles you add and the amount of contact they have with the soil. Limestone chunks from your driveway would not have as much surface area as either pelletized lime or ag lime (which are smaller pieces), and would not have much contact with the soil. You would be relying only on erosion or leaching of those limestone chunks, which would be relatively slow.
The pelletized lime you have on hand is preferable. There is information on using this in the home garden in this article: https://www.canr.msu.edu/news/growing-lavender-in-michigan-advice-for-a-purple-garden. The basic recommendation given here is to start by applying 1/8 of a cup of lime per square foot on the soil surrounding the plants.
I do not know of any home pH tests that are reliable. However, if your beds were filled during the same year using the same sources of sand and soil, you may be able to get away with kit-testing one bed each year in rotation, or even one bed every two years. Information for one should be representative of all three, assuming that all are in simular environments. (Note, for example, that if one has leaves on it throughout the winter and the others do not; or one gets run-off from the house and others do not, then they may not remain similar over time.)
Since anything you can do to raise the pH in these beds will help your lavender, my suggesion would be to start with the application of lime described above for 2024. Then, consider sending in samples from one bed in 2025 (instructions can be found at https://ohioline.osu.edu/factsheet/hyg-1132) - if your pH is satisfactory, then don't treat in 2025, and if there is still a ways to go to raise the pH enough, then treat again next spring. I am hopeful that your lavender will be showing you it is happier throughout this season as well, with increased foliage growth and deeper green color.
Best of luck with those beds!
