Quick Answer
Yes, it is generally recommended to put down lime before planting grass seed. Applying lime helps adjust the pH of the soil, making it more suitable for grass growth. Proper pH is crucial for seed germination and grass establishment.
Why Put Down Lime Before Seeding?
There are a few key reasons why it’s beneficial to lime before seeding a new lawn:
Adjusts Soil pH
Most grasses prefer a soil pH between 6.0-7.0. Lime raises pH in acidic soils, bringing it into the optimal range for grass growth. Soil testing can determine if the pH needs adjusting and how much lime is required.
Provides Calcium and Magnesium
Lime supplies essential nutrients including calcium and magnesium, which grass plants need. These nutrients are far more available to plants when the soil pH is properly balanced.
Improves Seed Germination
Lime creates a better environment for seed germination. It’s difficult for grass seeds to get established in overly acidic soils. Proper pH improves germination rates and helps young grass plants develop robust root systems.
Enhances Availability of Nutrients
Adjusting soil pH makes nutrients like nitrogen, phosphorus and potassium more plant-available. Grass needs these key nutrients to thrive, especially in the early growth stages after seeding. Lime unlocks these essential nutrients already present in the soil.
When to Apply Lime
Lime should be applied and worked into the soil before laying down grass seed. Lime requires some time to fully react with the soil, so it’s best to lime weeks or months ahead of seeding if possible. However, applying lime just before seeding is still beneficial.
Here are some tips for timing your lime application:
- Fall seeding: Apply lime 2-4 weeks before seeding
- Spring seeding: Apply lime in fall, or at least 4 weeks before spring planting
- New lawn construction: Till lime into the soil well ahead of laying sod or seed
- Overseeding: Apply lime 2-4 weeks prior if a soil test indicates the pH is low
Allowing lime enough reaction time before seeding will maximize its positive effects. But even applying lime right before seeding is better than not liming at all.
How Much Lime to Apply
The amount of lime needed depends on:
- Soil type and current pH
- Desired pH level based on grass variety
- Lime’s calcium carbonate equivalence (CCE)
Soil testing is the best way to accurately determine lime requirements. Home test kits are available, or you can send samples to a lab for analysis.
Without a soil test, a typical application is 50 lbs of lime per 1,000 sq ft, but this can vary significantly. Using lime with a high CCE value requires smaller amounts. Consider applying half the recommended rate, then testing the pH again before adding more.
It’s best to apply lime over two or more applications spaced several months apart, rather than dumping it all at once. This allows the lime to fully incorporate into the soil.
How to Apply Lime
Proper application technique helps ensure the lime treatment is effective:
- Choose pelletized lime if using a drop or rotary spreader. Powdered lime works for hand spreading.
- Water the lawn lightly before application to avoid drift of powdered lime.
- Use a spreader to achieve even coverage, avoiding heavy concentrations in spots.
- For a new lawn, thoroughly till lime into the top 6 inches of soil before laying seed or sod.
- Water gently after application to help lime seep into the soil.
- Allow 4-6 weeks for the lime to fully react before seeding or overseeding.
Applying more lime than recommended can burn grass plants. Follow label rates and spread evenly for best results.
Should You Add Fertilizer with Lime?
Lime and fertilizer work best when applied separately. Here’s why it’s usually recommended to avoid fertilizing at the same time as liming:
- Fertilizer acids temporarily lower soil pH after application. This counteracts the liming effect.
- Lime tie up soil minerals for a period, making them unavailable to plants. This can make fertilizer less effective.
- Applying both together increases the risk of burning grass with over-concentration of chemicals in spots.
- It’s difficult to evenly spread both materials together with a drop spreader.
For these reasons, it’s smart to apply lime and fertilizer in separate operations. Wait about 4 weeks after liming to apply starter fertilizer when planting new grass seed.
Types of Lime for Lawns
Not all liming products are created equal. The effectiveness depends on the source material and fineness. Common options include:
Agricultural Lime
Made from crushed limestone, this traditional liming product has a lower calcium carbonate content than some alternatives. May contain small amounts of magnesium. Very slow to react in soil but provides longer-lasting effects. Requires higher application rates.
Dolomitic Lime
Contains calcium carbonate plus magnesium carbonate. Adds magnesium to soils, which some plants need. Reacts more quickly than calcitic lime but doesn’t last as long in soil. Moderate solubility.
Calcitic Lime
Consists of nearly pure calcium carbonate. Very fast acting but effects are shorter-lived compared to agricultural lime. Ideal when a quick pH boost is needed. High solubility.
Pelletized Lime
Finely ground lime compressed into small pellets for easier spreading with rotary and drop spreaders. Quick reaction time and convenient application. Provides rapid pH adjustment.
Liquid Lime
Specially formulated lime suspended in liquid for spray application onto lawns and gardens. Provides immediate but temporary pH change. Multiple applications needed for lasting effect. Easy to apply through sprayers.
For establishing a new lawn, agricultural lime or pelletized lime are good options. Dolomitic lime adds magnesium if soils are deficient. Liquid lime offers a fast fix.
The Right Way to Lime a Lawn
Follow these steps for successfully liming an existing lawn or preparing soil for new seed or sod:
- Test soil pH to determine lime needs. Target slightly acidic pH of 6.0-6.8 for most lawns.
- Choose an appropriate liming product based on soil conditions and project timeframe.
- Apply lime at least 2-4 weeks before seeding or sodding to allow reaction time.
- Spread lime evenly using a drop spreader or by hand. Water gently after application.
- Allow 4-6 weeks for full reaction before fertilizing or planting grass seed.
- Test soil pH again after a few months and apply more lime if still needed.
Proper liming takes some patience but creates ideal conditions for grass to thrive. Healthy soil pH prevents many common lawn problems and helps grass better withstand traffic, diseases, and drought stress.
The Effects of Too Much Lime
While lime improves soil pH, over-application can have negative effects:
- Raises pH excessively, causing nutrient tie-up and availability issues
- Can burn grass plants when over-concentrated
- Leads to lawn moss and mushroom growth in very alkaline soils
- Prevents effectiveness of certain herbicides and pesticides
- Causes salt buildup and alkaline soil crusting
That’s why soil testing is recommended, so you don’t overdo it with lime. Visible damage from lime burn can appear as browning, dieback, or dead patches.
Applying more than 50 lbs of lime per 1000 sq ft at once is risky unless you know the soil is highly acidic. Follow product guidelines and retest pH before additional applications.
Can You Lime Too Often?
It’s possible to overdo lime with repeated heavy applications, but annual light liming is beneficial for most lawns.
Here are some tips for liming lawns on an ongoing basis:
- Test soil pH yearly and only apply lime if needed
- Limit additional lime apps to 25 lbs or less per 1000 sq ft
- Wait at least 3-4 months between lime treatments
- Alternate between fall and spring liming for best effects
- Monitor lawn soil and grass health for any warning signs of over-liming
Frequent light liming is far better than heavy shock treatments every few years. A little lime goes a long way when applied correctly.
Signs Your Lawn Needs Lime
Some visible clues suggest a lawn could benefit from liming. These include:
- Moss growth – Moss prefers acidic soil, so heavy moss indicates very low pH
- Poor grass growth – Weak or stunted grass can be a pH-related issue
- Leggy growth – Excessively upright growth signals nutrient deficiencies
- Discolored grass – Yellowing or browning could mean low pH or nutrient lockup
- Bare spots – Grasses failing to thrive due to low pH
- Weeds – Certain acid-loving weeds like oxalis and chickweed
While these symptoms can have other causes, soil acidity is a top suspect. A pH test will confirm if lime is needed for healthier grass.
Does Lime Go Bad or Expire?
Bagged lime has an almost unlimited shelf life if stored in a dry area protected from moisture. Over time, lime can harden in the bag but is still effective once broken up.
Properly stored lime does not really expire or go bad. However, it’s best to use pelletized lime within a year or two for optimal results. Powdered lime may slowly lose reactivity over many years of storage.
Check old bags of lime for solid clumps or cement-like hardness. If still in good condition, there’s no issue with using lime that’s been stored for years. But very old lime may not react as vigorously as fresh product.
For best results, buy lime in quantities that will be used up within 1-2 seasons. Store in a shed or garage to protect bags from rain and moisture.
Conclusion
Applying lime before seeding or sodding is an essential step for establishing a healthy, thriving lawn. Lime adjusts soil pH, provides calcium and magnesium, unlocks nutrients, and creates the ideal conditions for turfgrass success. Use soil test results to determine lime requirements before application. Allow enough reaction time for the lime to work before planting grass seed. Proper timing, product selection, and application techniques will ensure liming effectiveness. Avoid over-applying lime, which can burn grass and create more problems. With the right amount of lime at the right time, your new lawn will get off to the healthiest start possible.
