Is it Safe to Apply Lime Before Rain?

Only apply lime before rain if the expected rainfall is light and brief. Heavy rain or extended periods of rainfall can saturate your soil with water, causing lime to run off your lawn and be wasted. Although lime needs to be watered in after application, this is best done by providing 15–30 minutes of water from a sprinkler system. To get the best soil penetration from your lime application, apply when no rain is in the forecast for at least 3 days. Use a sprinkler to water in the lime in a controlled manner.

Does Rain Wash Away Lime?

Heavy rainfall that exceeds one-half inch (1.25 cm) can wash away both powdered and pelletized limestone spread on your lawn. This is due to the fact that lime penetrates soil very slowly, especially if there is grass already growing on the lawn. Lime may only penetrate at the rate of 2 inches per year in poor conditions, so it must be watered in gradually. An excess of water will carry your lime away as runoff rather than pull it into the soil.

• Rainfall greater than 0.5 inches (1.25 cm) can wash away your lime application.
• Powdered lime is extremely susceptible to being carried away as runoff, as it can be picked up by water easily.
• Lime is slow to penetrate the soil. It washes away more easily than fertilizer or pre-emergent herbicide.

Because lime is really just limestone that has been baked and crushed, it doesn’t have the benefit of being formulated to dissolve in water and enter the soil. Fertilizers and pre-emergent herbicides that are designed to be watered into the soil can withstand up to 1 inch of rain without fear of them running off your lawn.

Check Before You Apply Lime

Before you add lime to your yard, make sure your grass needs it. A soil test must be performed to determine soil pH levels. Grass thrives when pH is between 5.0 and 7.0. If the pH is below 5.0, your soil is acidic and needs lime.

• Perform a soil test or send soil samples to a local University Extension for testing before applying lime.
• Soil only requires lime if the pH is below 5.0.
• Apply recommended pounds of lime per square foot to correct pH. Do not apply more than 50 pounds of lime per 1,000 square feet in one season.

If you have your soil tested by a local extension, they can help by recommending the amount of lime to apply to your lawn. Overapplication of lime can reduce soil acidity too sharply, which is just as bad for your grass as overly acidic soil.

Can You Apply Lime to Wet Grass?

Do not apply lime to a yard that has recently been saturated with water from rainfall or excessive watering. Lime applied to wet grass may be washed away, especially when you attempt to water it in. Wet grass is a sign that the lawn is already saturated with water and the soil can’t currently absorb any more moisture. Lime applied to a wet lawn will not be absorbed.

• Avoid applying lime to a lawn with wet grass and standing water.
• Do not apply lime to an extremely dry, brown, or dormant yard.
• For best results, water 1–2 days before lime application, so the soil is moist but not wet when you spread lime.

Similar to extremely wet soil, hard-baked soil can be compacted and dry and may resist initial watering, instead of shedding the water as runoff. This can carry your lime application away. To make sure your limestone is pulled into the soil where it can improve nutrient availability in acidic soils, water your lawn 1–2 days before application. Soil and grass blades should be moist but not wet at the time of application.

Is it Better to Apply Lime Before or After Rain?

You’ll get the best results by spreading lime where there is no upcoming rain. If it has recently rained, wait 1–2 days before you spread lime. This ensures that soil is moist but not saturated. Applying lime when there is no incoming rain allows you to control conditions and water lime in gradually.

• If possible, apply lime when it has not rained recently and no rain is in the forecast.
• Wait 1–2 days after rain before spreading lime. This gives the soil time to shed excess water.
• If you must spread lime when rain is in the forecast, make sure is very light rain.

Lime application will only benefit from a very light rain that continues for no more than 1 day. A brief, heavy storm can wash out lime. Long periods of extended drizzle can also saturate the soil and wash away your limestone application.

Does Lime Need to be Watered In?

Lime must be watered into soil to be effective. Lime works by penetrating the soil, where it introduces calcium and magnesium as it corrects soil pH levels. Water is essential for pulling lime down into the soil so it can benefit plants and make your yard less hospitable for weeds.

• Lime must be watered in to be effective.
• Lime left on the surface will not provide nutrients such as calcium and magnesium.
• Unwatered lime will not reduce soil acidity.

Lime balances soil by penetrating it and mixing with soil particles to change the chemical balance of your yard. This takes time and patience, as lime is relatively slow-acting. Patient watering yields the best results.

How to Properly Water Lime Into Soil

Plan to water your lime in directly following application. This allows you to get the lime started in your soil before wind or rain can carry it off. As soon as you spread your lime, use your sprinklers to give your yard 15–30 minutes of water.

• Water lime in immediately after application to prevent loss from wind or other factors.
• Use a sprinkler system to water areas of lime application for 15–30 minutes.
• A sprinkler system is more reliable for applying the correct amount of water in a timely fashion than relying on mother nature.
• After an initial watering, return to your standard lawn watering schedule.

Your standard watering schedule for turf grass should provide enough water to keep your grass healthy and pull lime deeper into the soil without the risk of washing it away. This is why it’s a great idea to apply lime when no rain is in the forecast. You can gradually water in lime and get it deep into the soil before any storms arrive.

Should You Apply Lime When Rain is in the Forecast?

Under ideal circumstances, you should apply lime when there has been no rain for 1–2 days and no rain is expected in the following 3–5 days. This allows you to spread the lime, water it in with 15–30 minutes of water from the sprinkler, and put your lime application to work. Too much rainfall carries the risk of washing away lime. You’ll provide the most benefits to the plants in your lawn and garden by applying limestone at a time when you can control how much water your lawn receives.