Lime and acidifying soil for blueberries
I had a huge problem with wild onions in my garden - too many to dig out individually. I spread a bag of lime on the garden to try to eradite them. One end of my garden plot has about a dozen blueberry plants and I know that the lime will probably reduce the acidity in the soil and possibly damage the blueberries. What would you recommend that I do around each of the blueberry plants to maintain the acidity in their immediate area?
To maintain or lower the pH for blueberry plants I would recommend using either mineral sulfur or sulfur dust around the root zone to get the pH at the correct level. Blueberries do well with a pH of 4.5-5.0 if you have not had the pH tested for your soil I would encourage you to do that. You can either send a soil sample to a lab or buy a simple soil test kit at a farm and garden store. You will only know how much sulfur to add around your plants if you know what the pH is currently. If the pH is between 5 and 6 add a cup of sulfur each year for three years around each plant. If the pH is below 5 then just add a cup once and that will be adequate for several years.
Onions prefer a soil with a pH between 6.5 and 7.5 so adding lime to your garden to help control the wild onions will probably just help them grow better. The lime and a more neutral pH soil will be good for your other vegetables too however. I think you will just have to dig a lot of small onions over time to rid the garden site. Their are herbicides that will kill the wild onions but you wont want to use them in the vegetable garden.