Gardenias, azaleas, rhododendrons, hydrangeas, blueberries, spruce, pine, maple, oak – the list goes on and on of plants that grow best in acidic soil. If you love acid loving plants and the ph of your soil is below 7, you won the acid soil lottery. Plant away! But what if your soil is alkaline and you have a love for acid loving plants? There are many synthetic means available to acidify your soil but there are also ways to do it organically. By adding specific amendments to the soil, you can lower the ph naturally.
Tip: Creating an acid soil situation where there wasn’t one before may injure alkaline-loving plants nearby. If you choose to acidify your garden soil, use care so you don’t damage nearby plant life.
Amending The Soil
If you have plants that prefer acidic soil or you would like to add plants to your garden that prefer acidic soil, you can amend the soil to lower the ph if necessary. Plants prefer acidic or alkaline soil because the chemistry of the soil determines which types of nutrients in the soil are available to your plants. For example, alkaline soil chemically binds up the iron that is already in the soil. This makes most of the iron in the soil unavailable for plant use. Because acid loving plants require a good deal of iron to thrive, this situation results in iron deficiency. A lack of iron results in a condition, called chlorosis. It is generally identified by a yellowing of the leaves on the plant. When the soil is amended to create a more acidic soil condition, the iron that is already present in the soil is chemically released and becomes available for use by the plant.
Tip: Changing a soil’s ph level is generally a slow process that may take several applications and a lot of time before it takes effect, even with chemical treatments. Have patience my friends!
Sphagnum Peat and Peat Moss (Best Option)
Sphagnum peat and peat moss, which are highly acidic, are the best means of lowering the ph of your soil naturally. (Hint: It also adds organic matter to the soil which improves soil structure!) These materials lower the ph of your soil while they break down. Adding peat or peat moss along with compost to your acid loving plants every year will make your acid-loving plants very happy and it will improve you soil structure as well. Also, in my opinion, this is the safest and easiest way to acidify your soil naturally.
The soil in my area is quite alkaline. I planted an azalea with a soil mixture of 50% soil and 50% sphagnum peat moss. Then every year after that, I added a hardy layer of sphagnum peat moss around the azalea and it grew quite nicely.
Mulching with Pine Needles
There are current ongoing arguments over the idea of whether or not pine needles will acidify the soil. Scientists are saying that while pine needles are acidic while they are on the tree, they lose that acidity fairly quickly once they fall to the ground and by the time they are decomposed their ph is at a neutral level. But, life-long gardeners swear by using pine needles as a natural mulch to acidify the soil. In this debate, you will have to choose a side but my advice to you is this: if you have pine needles readily available, use them as a mulch around your acid loving plants. It won’t hurt. Even if pine needles don’t acidify the soil, they will improve the soil structure as they break down into compost.
The arguments concerning pine needles are the same with oak leaves. Again, it never hurts to mulch with them or add them to your compost!
While conducting research for this article, I read numerous articles and watched a multitude of videos about watering plants with a water/vinegar solution to acidify soil. Personally, I wouldn’t try this. Vinegar is a natural herbicide (i.e. plant killer). It would be far too easy to burn or kill your beloved plants. And from what I read, it only acidifies the soil slightly and the results are short-lived which would require the process to be repeated frequently. My suggestion – don’t do it.
For more information on acidifying garden soil, check out the Iowa State University Extension website.
My best advice to you is to grow plants that like alkaline soil if you have alkaline soil and acid loving plants if you have acid soil. If you really love a plant that likes acid soil and you have alkaline soil, grow the plant in a pot with potting mix for acid loving plants and enjoy, enjoy, enjoy!
Happy Gardening my friends!
Quote of the Day
“God grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference.”
-Reinhold Niebuhr, American theologian