Learn which plants thrive in your Hardiness Zone with our new interactive map!

The Effects of Acidic Soil

By Kate Carpenter ; Updated September 21, 2017
Many plants struggle to survive in acidic soil.

You can have your soil tested inexpensively at your local cooperative extension office to discover the pH value. The soil pH scale ranges from zero to 14. Ideally, your soil pH should be around 7, where the alkaline and acid are equally balanced. A higher number means your soil is alkaline; lower numbers reflect an acidic soil. Lime is usually added to soils that are too acidic to balance the soil. High-acid soils affect the productivity of your garden.

Symptoms of Acidic Soil

If your flowering plants show a lack of vigor and your vegetables are not producing well, they may be suffering from the effects of acidic soil. Plants grown in acidic soils have weak, shallow root systems, making it more difficult for the plants to take up the needed nutrients and water in the soil. This leads to a less vigorous plant and decreased production. Acidic soil can also cause abnormal leaf color, an increase in disease, and robust weeds that are more tolerant of acidic soils.

Soil Quality

Too much acid in your soil affects the nutrients available for your plants. Due to leeching, the valuable minerals potassium, calcium and magnesium are depleted in acidic soils. If aluminium is in your soil composition, it can be released when your soil is more acidic. At a pH reading of five or lower, aluminium becomes toxic to plants and will severely restrict plant root growth. The biological activity that creates essential nutrients will be reduced and may cease if your soil contains too high a level of acid.

Correcting Acidic Soils

Decreasing the acid value of your garden soil is not difficult or extremely expensive. If your soil was tested by the cooperative extension office and indicated a pH lower than six, work lime into your soil. The amount varies according the type of soil you have. A general guide for sandy, loamy soil is 35 lbs. of lime for every 1,000 square feet. Medium loamy soil needs 50 lbs. per 1,000 square feet, and clay soil needs 70 lbs. Work this into your soil, then re-test the pH level in three weeks. Add more lime if needed at that time. If you have raised the pH level over 7.5 pH, lower the pH with a little sulphur worked into your soil. There is no scientific method to supplementing your soil for an ideal pH reading; experimenting with additives and repeated testing will eventually yield best results.