Lime and Gypsum Buying Guide

Improve your soil pH and saline levels with lime and gypsum

Improve the color and health of your lawn by adding lime or gypsum to the soil. This guide will teach you which additive is best for your grass.

Lime vs. Gypsum

Adding lime to soil raises the pH, which lowers the acidity. Gypsum helps correct compacted soil as well as counteract excessive saline levels.

Tip: Lower soil acidity can help increase vegetable production in the garden and enhance the appearance of your lawn.


Do I Need Lime? 

The best way to determine whether your soil needs liming is to test its pH. Since the most fertile gardens and lawns are those with a proper pH balance, having your soil tested every few years is highly beneficial.

The target pH level of turf grass is between 6.2 and 6.5, so if your soil has a lower pH it will likely benefit from the addition of lime.

Remember, though, too much lime can be as harmful to your lawn as too little, so always test the soil and read the instructions on the lime package before application.

Do I Need Gypsum? 

To determine if your soil can benefit from gypsum, test saline amounts or simply observe if you are working with soil that is heavy with clay or hard to break up.

Characteristics Tips

Lime

  • Compound made of calcium or calcium and magnesium
  • Reduces damaging effects of acidic soil on lawns and gardens
  • Calcitic and domestic lime most commonly used in gardening
  • Adds desirable nutrients such as calcium and phosphorus, and increases bacterial activity to improve soil structure
  • Soil in the Eastern U.S. often requires the addition of lime to reduce acidity
  • Vegetables thrive in a slightly acidic soil, with a pH between 5.8 and 6.3
  • Adding too much lime to soil can damage it as much as having high acid levels

Gypsum

  • Actually an element called calcium sulfate
  • Pulls together clay particles in the soil to make bigger particles, creating porous spaces for air, water and plant roots
  • Removes sodium in soil and replaces it with calcium and sulfur, which help boost plant growth
  • Helps soil retain water and decrease erosion
  • Gypsum will not alter pH levels
  • Soil in the Southeast U.S. often contains clay and may benefit from gypsum, as will arid and coastal regions with high soil salts
  • Can correct lawn damage from salt and other winter ice-melting chemicals

Application

Lime and gypsum are easily applied using a drop spreader or broadcast spreader. As with all fertilizers, apply lime and gypsum as the label directs.

Both lime and gypsum are nontoxic. Since lime is insoluble, it tends to stay exactly where it is spread, so spreaders ensure uniform coverage. Gypsum does not change the pH of your soil so you can use it around acid-loving plants such as rhododendrons and azaleas to provide extra calcium.

  • Although best applied in the fall, lime can be applied at any time.
  • For even coverage, apply half the lime in one direction and the rest in a crisscross pattern.
  • Apply lime and fertilizer at least two weeks apart to avoid damaging plants.
  • Both lime and gypsum can be easily applied using lawn spreaders.
  • Lime can burn a lawn if misapplied, but gypsum will not.



Additive Season Quantity Frequency Application

Gypsum

Any time of year

  • Established lawns: 40 to
    50 lbs. per 1,000 sq. ft.
  • New lawns w/ heavy
    clay: 300 lbs. per
    1,000 sq. ft.
  • Gardens: 20 to 30 lbs.
    per 100 sq. ft.
  • Roses: 1 lb. per
    bush Shrubs: 2 lbs.
    per shrub
  • Evergreens: 2 to 3 lbs.
    per evergreen

Twice per year

  • You do not have to
    work gypsum into
    the soil -- simply use a
    spreader to distribute it
    over the surface of
    your lawn or garden
  • For garden application,
    also mix in compost or
    organic matter
  • Water immediately after
    application

Lime

Fall, winter or early spring

20 to 30 lbs dolomitic lime per 1,000 sq. ft.

Every 3 to 5 years

  • For new lawns, mix lime
    deeply into soil a day
    or two before planting
    or seeding
  • Use a spade to work
    the lime 6" into the soil
  • For existing lawns,
    distribute evenly over
    lawn or garden with a
    spreader
  • Water soil to encourage
    chemical reaction