One of the more common symptoms of soil PH problems is yellowing foliage. When the PH of your soil becomes too acidic or too alkaline, certain nutrients and micronutrients can be ‘locked out’. This simply means that the roots of the plant are unable to uptake the desired nutrient and the plant effectively starves for it (even if there is ample food at the roots). When lavender is unable to uptake and process Nitrogen, one of the first (and very telling) symptoms is the foliage will begin to yellow. This normally starts in the lower, older leaves. The reason for yellowing is that the plant begins to draw upon it’s own internal stores of Nitrogen- in it’s leaves. By effectively cannibalizing itself, the plant can live on weeks and months without enough food (much like we humans burn our excess fat stores when we diet). This is not healthy, but can be corrected if caught early enough and the cause identified. Check your soil PH with a meter- it should fall in the 6.5 – 7.5 range for the best uptake of nutrients, and if it is too high, try adding acidic mulch. If your PH is too low,add alkaline in the form of oyster shells or a light dusting of lime (use sparingly). Plants will generally not regain much color in the affected areas, but new growth should pick up and be strong.