Every commercial property owner strives to have a lush, green lawn that is the envy of all your competition. There is a common thought that fertilizer = green so it is not uncommon to see 2-3 fertilizer applications in an annual maintenance agreement. It’s hard to imagine a lawn could look bad with all those supplemental nutrients, but it can. If despite your best efforts, your property’s turf is thin, weed-filled, or in an overall state of decline, we can only offer one piece of advice – GO DEEPER. No literally – look beneath the surface because it may be time to lime. Liming is a widely overlooked service in annual maintenance contracts but could be the answer. So what does lime do and why is it important?
To really answer that question, we have to lay the foundation by talking basic soil chemistry. Nutrient availability is largely determined by the pH of the soil. pH is the measurement of the acidity or alkalinity of a substance – in this case, the soil in the root zone of the turf. Now I won’t bore you with technical explanations of pH is determined because really what we all need to know is this:
- pH ranges from 1-14 with 1 being extremely acidic, 14 being extremely alkaline, and 7 being neutral
- When pH strays to one extreme or the other, nutrients cannot be absorbed because they are being tightly held by the soil thereby being unavailable to the turf root mass
- Lawns prefer a relatively neutral soil (pH 6.5 – 7.2)
- pH changes as a result of fertilizer applications and rain and tends to become more acidic with time
- Adding lime to soil raises the pH back to a more neutral range and frees up tightly held nutrients for root absorption
What is Lime?
Lime is a soil conditioner made from limestone, which is high in Calcium. It is typically ground into a powder or pellet and applied to the surface of the lawn. Lime is not a fertilizer, but rather an additive that raises the pH of the soil and makes nutrients available to the turf roots. Even when nutrients are plentiful in the soil, they cannot be absorbed if the pH is not in the optimal range. Lime helps to remedy that situation and makes the fertilizer that is being applied seasonally useful again.
Signs That You Need Lime
When soil has become acidic, moss and turf weeds will begin to take over. Weeds prefer more acidic soils and will thrive in a lower pH. As the weeds grow stronger, the turf will show signs of stress from lack of available nutrients, and as it becomes weak, the turf will eventually be overrun with weeds and moss. It will also appear like the lawn may not be getting fertilized because the lawn will be discolored and thin.
How Much Lime Do We Need?
This question can only be answered with a soil test. Soil tests can show many characteristics of the soil including pH, nutrient content, texture, and more. When a soil test is performed by a reputable soil lab, they will show what the current state is, but they will also make recommendations to bring the soil back into optimal range so that nutrients can be used by the plants and turf. Because soil pH can change, but it takes time to do so, it is recommended that soil tests be taken once every 3 years.
When Should Lime be Applied?
While lime can be applied at any time of the year, a good practice is to apply lime in conjunction with aeration and overseeding in the fall. Aeration is the process of loosening the soil by removing small “plugs”. When lime is applied at the same time, there is a greater surface area of soil exposed to the lime and that helps to accelerate the effectiveness of the lime. Fall rains and winter snows also help the lime incorporate into the soil and break down which helps to lower the pH faster.