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Mag-I-Cal® for Lawns in Acidic Soil

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  • One bag of Mag-I-Cal® has the pH adjusting power of up to 15 bags of limestone!
  • Rapidly raises and balances low soil pH
  • Stimulates microbial life to create a healthy environment for grass
  • Increases grass roots ability to absorb nutrients
Real Mag-I-Cal Lawns
Product Overview
Adjust your soil with Mag-I-Cal®! Jonathan Green Mag-I-Cal® for Lawns in Acidic Soil helps rapidly raise soil pH that's too low and stimulates healthy microbes in the soil. Healthy, lush lawns thrive in soils with slightly acidic to neutral pH levels ranging from 6.2 to 7.0. When soil pH levels drop between 4.0 to 6.0, this creates an environment for weeds to thrive and grows a lawn full of light green unsightly grass.

Mag-I-Cal® for Lawns in Acidic Soil contains pelletized calcium carbonate, or lime, in a completely soluble form that is immediately available to rapidly and efficiently raise soil pH upwards. Poor soil is often the problem in growing a great lawn and calcium is vital to many grass plant functions. Where it may take several bags of lime to balance low soil pH, Mag-I-Cal® for Lawns in Acidic has the power to do it all in just one easy application!

Additionally, Mag-I-Cal® for Lawns in Acidic contains humates to stimulate beneficial microbes in the soil.
Coverage Guide

For soils with a pH over 5.9, use the new lawns rate.


Established Lawns
New Lawns
18 lb
Up to 5,000 sq. ft.
Up to 2,500 sq. ft.
54 lb
Up to 15,000 sq. ft.
Up to 7,500 sq. ft.
How Do I Calculate My Lawn Size? First measure the length and width of your lawn. Then multiply the length by the width and deduct the square footage of any non-lawn areas (landscape bed, patio, deck, pool, etc.) from the total. Now you know how much product you need to purchase!
Shipping & Returns


  • Free ground shipping now available on orders of $75 or more! For smaller orders, shipping costs are calculated at checkout.
  • We ship orders the same day if placed by 2PM EST (later orders will be shipped the next day).
  • Orders are not shipped or delivered on weekends or holidays.
  • We offer ground and expedited shipping.


  • We offer 30-day free returns for replacement or full refund for items that are damaged or defective (shipping included). If damaged by the carrier, please file a claim with them.
  • If your items have been used or aren’t in the original packaging, we will give you a refund (minus the cost of shipping) based on the condition of the product.

View our complete shipping and return policy. If you have questions about your order, please contact our customer service team at orders@jonathangreen.com.

  • This product can be applied throughout the United States and performs well on both cool and warm-season lawns.

  • For cool and warm season lawns, apply in either spring, summer or fall when air temperatures are at least 45°F.

  • Calcium (Derived from: Calcium Carbonate)


    Also contains non-plant food ingredients: humic acid (derived from humus), polyhydroxycarboxylic acids (derived from plant extracts).

  • Mag-I-Cal® for Lawns in Acidic Soil contains natural ingredients and can be applied with any of our grass seeds, weed controls, fertilizers, and insect and lawn disease controls.

    • For a pH of 5.9 to 6.7:

    Apply Mag-I-Cal® Plus for Lawns in Acidic & Hard Soil once per year.

    • For a pH of 5.9 or below:

    Apply Mag-I-Cal® Plus for Lawns in Acidic & Hard Soil twice per year (at least one month apart).

  • Mag-I-Cal® for Lawns in Acidic Soil is a natural product, meaning it is safe for children and pets to re-enter the lawn immediately after application.

    • Carefully read all instructions prior to application.
    • Store in a cool, dry place away from children and pets.
    • Do not ingest. May cause irritation to eyes and skin.
    • Wash hands thoroughly with soap and water after handling and before eating or drinking.
    • Do not apply near water, storm drains, or drainage ditches.
    • Do not apply if heavy rain is expected.
    • Apply this product only to your lawn or garden and sweep any product that lands on the driveway, sidewalk or street back onto your lawn or garden.
  • Always read and follow the product label before use.




    Safety Data Sheets can be found at www.jonathangreen.com/safety-data-sheets-sds. If you have a specific question, do not hesitate to contact us.


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Step 1/4

Who makes your spreader?

Jonathan GreenScottsAgri-FabBrinly-HardyCycloneEarthway / AmesEchoGreenViewLescoOrthoPrecision / Red DevilPrizeLAWNQuaker / Lawn CrafterRepublic / EZSearsSpykerSta-GreenViconVigoro

Don’t see your spreader here? Contact the manufacturer or review your spreader’s manual.


Step 2/4

What type of spreader are you using?

Rotary Drop Handheld


Step 3/4

What is the model of your spreader?

Agri-Fab Push Broadcast Agri-Fab Tow Broadcast Agri-Fab Drop Agri-Fab Tow Drop BS26,36 Cyclone Rotary EV-N-SPRED® Broadcast Earthway Rotary Ames Broadcast Earthway Drop Ames Drop Echo RB 60 Jet Spred III Standard Deluxe and Pro Green-Meter Hand Crank Lesco (Lettered) Lesco (Numbered) Ortho Rotary Ortho Drop Precision Rotary Red Devil Rotary Precision Drop Red Devil Drop Prizelawn CBR III Prizelawn CBR IV Prizelawn Lil\' Foot Prizelawn MPR-1 Lawn Crafter Broadcast EZ Drop All Rotary Turf Builder Classic AccuGreen 2000-3000 AccuGreen 1000 Scotts PF4 Wizz Sears Broadcast P70-12010 Spyker Rotary Rotary Vicon Rotary

Don’t see your spreader model here? Contact the manufacturer or review your spreader’s manual.


Step 4/4

Select the rate that best suits your lawn needs.

Depending on the type of product you selected there may only be one application rate.

Existing Lawn Rate - 3.6 lb per 1000 sq ftNew Lawn Rate - 7.2 lb per 1000 sq ftExisting Lawn Rate 3.6 lb rate per 1000 sq ftExisting Lawn Rate - 3.6 lb rate per 1000 sq ft

Note: “New lawn” indicates that you are starting a lawn from bare dirt vs overseeding or applying product to an existing lawn.


Mag-I-Cal® for Lawns in Acidic Soil

Your Spreader Setting is:

Start over
  • How do I test soil pH?

    You can test your soil’s pH by sending a soil sample to your state university cooperative extension office, who will send it off to a lab for a small fee, or by using an at-home testing kit.


    To perform a soil pH test with the Jonathan Green Soil pH Test Kit, follow these steps:


    1. Collect soil samples from your lawn

    Gather small soil samples from four different sections of your lawn by using a gardening trowel to dig four to six inches deep into the lawn’s surface. Mix all four small samples together for one, cohesive sample to use for your test. Make sure to remove all debris from your sample and proceed to the next step.

    2. Fill test container with soil sample

    Once you have your comprehensive soil sample, remove the cap off of the color comparator and take out the capsule. Make sure the pH color chart is in place, then fill the test container with your prepared soil sample. Carefully separate the two halves of the capsule and pour the contents into the test container.

    3. Add disilled water to the test container

    Using the provided dropper, add distilled water to the test container. Do not use tap water for your soil pH test, as it usually contains acidic or alkaline components.

    4. Shake test container and allow to settle

    After adding distilled water to the test container, shake thoroughly and allow the test container to settle for one to five minutes.

    5. Observe test container for results

  • Can I use your products in my garden?

  • How to take a soil sample

    Steps to take a soil sample


    • With a shovel or a spade* dig a V-shaped hole to sample depth of 4-6 inches (excluding any thatch), then cut a thin slice off to the side.
    • Do this in 4 or 5 places in the section of the lawn to be tested.
    • Mix soil samples together in a clean, plastic bucket. If the bucket has been used to hold fertilizer or other chemicals, wash it thoroughly before using it for soil samples.
    • Let the sample dry well before testing. Place it in a ziplock bag or coffee can. Approximately one quart is recommended.
    • Make sure to use distilled water for testing.


    *Tools should be either stainless steel or chrome-plated. Do not use brass, bronze, or galvanized tools because they will contaminate samples with copper and/or zinc.

Features You’ll Love

Correcting acidic soil is critical to the health of your lawn but it can be a major chore spreading dozens of bags of lime. Our Mag-I-Cal® for Lawns in Acidic Soil is a highly effective, one-bag solution to raising your soil pH and supporting healthy soil for the long-term.

Say Goodbye to Multiple Bags of Lime

Mag-I-Cal® for Lawns in Acidic Soil rapidly raises soil pH levels in an easy, one-bag solution! This revolutionary soil amendment is designed to save you time and money with the adjusting power of not one, but 15 bags of lime for lawns in a single application.
Say Goodbye to Multiple Bags of Lime

Create a Healthy Soil Environment

Neutral soil pH creates the ideal environment for your lawn to thrive. This innovative product balances acidic soil to unlock and release vital nutrients that were not previously available to your grass.
Create a Healthy Soil Environment

How to Apply


Test Soil

Test your soil pH to check that it is in a healthy range for grass plants to grow. Optimal pH for cool-season lawns is 6.2 to 7.0.


For best results, rake the lawn vigorously prior to application to remove debris and thatch.



Use a spreader suitable for your specific lawn size. Set the spreader according to the recommended setting on the packaging or use our Spreader Settings Tool above. Make sure to update the setting with each product you apply.


Begin by spreading along the perimeter of your lawn. Make straight passes back and forth across the length of the lawn in a mowing pattern until the entire area is covered. Overlap slightly between passes and close the hopper when turning. Walk at a steady pace for even distribution.


To avoid staining, sweep any excess granules off of hard surfaces and back onto the lawn or garden.



Irrigate the treated area after application for 15 – 30 minutes for the best results.


Once watered, wait a day to mow the lawn to give the product time to activate.

Mag-I-Cal® for Lawns in Acidic Soil 5,000 sq. ft.
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