FAQ: What causes acid soil and how can I fix it?
The leaching action of rainwater, CO2 from organic decomposition, and oxidation of constituents in fertilizers all contribute to the formation of acid soil.
While some plants, like rhododendrons and blueberries, prefer an acid soil, most do not. But acid soil can be fixed.
Back in the day, grandpa may have added lime or wood ash to fix the soil. Today’s growers, however, are more likely to add compost.
With its neutral pH, compost makes an ideal amendment for both acidic and alkaline soils.
Get it tested
Don’t guess. Test your soil at least once every three years. Keep copies of those test results so you can monitor soil changes over time.
Pull a sample for testing through your local Cooperative Extension Service office or buy a kit. Sample several locations, then mix together.
Do not use a metal trowel, shovel, or bucket to do your sampling unless you are certain it is stainless steel. Some metals can react with the soil and distort results. For the same reason, don’t use painted tools, either. Plastic will be the better choice.
An inexpensive meter will also get the job done and costs about the same as testing or a DIY kit.
Find the Goldilocks zone
A pH range of 6.0 to 7.0 is considered ideal. (Acidic soils are on the low of the range; alkaline soils are on the high end.)
For overall soil and plant health, keep pH readings in the Goldilocks zone.
Sorry, but there’s no quick fix for soil pH
It takes time to adjust soil pH. Experts say if you’re able to nudge the number .5 to 1 point in a season you’re doing a good job.
It takes at least three weeks for early results. Making a start in the fall for spring planting is even better.
If you make your own compost, pH testing prior to soil incorporation can be a good idea. The specific ingredients in your compost will influence pH.
The same is true for commercial compost products. Compost manufacturers will provide copies of their product testing results, which should include pH. If these types of analyticals are not available, either choose another product or test it yourself.
If you have a choice, and your soils are slightly acidic, opt for the compost product that leans toward the alkaline. If your soil is more alkaline, choose a compost with a lower pH number.
In addition to compost, you can also add things like coffee grounds (acidic) and baking soda (alkaline) to either the compost or the soil to shift pH levels.