Fertilizers or Lawn Manure: When, How, Why, and Which?

Lawn fertilization is necessary to balance nutrients and prevent disease, thinning, and yellowing. In this guide we explain how to choose the best lawn fertilizer, when to fertilize and how to do it, giving you the information you need to create a green, resistant and lush lawn.

Most of the time, we think that the only care for our lawn is watering and cutting each season, which, without a doubt, are essential tasks, especially cutting at different heights in different seasons. I make a parenthesis here: if you still do not have a good lawnmower that allows you to move the height of the cutting blades, you should take action and get one.

Coming back to the subject, many of the problems with our lawns have to do with the fact that we forget the third most important thing: “Lawn fertilizer”. Let’s learn more about lawn fertilizer.

Why use lawn fertilizer?

The lack or incorrect balance of these elements causes stress and suffering to the grass, which will be weaker and subject to damage such as

  • disease vulnerability
  • Unevenness, thinning, dry areas
  • yellowing
  • little resistance

That is why fertilization is a cultivation practice that must be known and carried out regularly, using the best fertilizers and fertilizers for the lawn. It is important not to be dazzled by the promises of cheap low-quality products, the development of fertilizers and biostimulants requires experience and knowledge that only a few producers can guarantee.

In addition, the savings offered by low-quality products are usually fictitious, the price of lawn fertilizer is mainly determined by the quantity and quality of the elements that make it up. In cheap fertilizers, these elements, in addition to being of lower quality, are present in reduced quantities, with the result of having to distribute more fertilizer, and spending much more in the end.

What nutrients does the lawn need?

The main nutrients (macronutrients)  that the lawn needs are:







Stimulates vegetation and protein synthesis




It stimulates photosynthesis, seed germination and root growth.

(P) o (P 2 O 5 )


It stimulates the formation of cell walls and the exchange of water with the soil and the atmosphere.

(K) o (K 2 O)

In addition to these 3 elements, the lawn needs other nutrients  in smaller amounts

  • Mesoelements : calcium (Ca), magnesium (Mg), and sulfur (S).
  • Microelements : iron (Fe), zinc (Zn), manganese (Mn).

Nitrogen: fundamental element

The key element for grass growth is nitrogen.

In the best lawn fertilizers, this element is available in two forms:

  • Fast-acting nitrogen (nitric, ammoniacal, and urea nitrogen): generates a fast response in the turf lasting about 3-4 weeks
  • Slow-release nitrogen (zeolitic, organic, IBDU, SCU, methylene urea, etc.): generates a  medium-long-term response that can be  quantified from 4 weeks to 2-3 months depending on the product.

Nutritional uniformity is important to consider: Slow-release lawn fertilizers are preferable to traditional ones as they release the substances they are made from gradually and steadily over time.

When to fertilize the lawn?

It is important to use a lawn fertilizer in spring and autumn to help and enhance vegetative development in these fundamental seasons. But it is also necessary to fertilize in summer and winter when development is slower.

Experts recommend carrying out four fertilization cycles during the year, each season needs different substances to cover the different nutritional needs of the lawn.

  • Fertilize the lawn in spring

A mainly nitrogenous fertilization is necessary to strengthen the vegetative recovery of the lawn.

The lawn in winter has suffered from a prolonged lack of nitrogen, a treatment with professional fertilizer for lawns with timed-release serves to ensure a constant release of nitrogen for 60-90 days, as well as an immediate greening effect.

  • Fertilize the lawn in summer

It is necessary to use a lawn fertilizer with a predominant potassium base , to limit the stress of the summer heat and to strengthen and make the grass resistant. A professional fertilizer that releases immediate release potassium and gradual release nitrogen over the next 2-3 months is preferable. Potassium plays an important role in the neck of the plant, making it more resistant to thermal stress caused by heat.

  • Fertilize the lawn in the fall

As in the spring, we will use a fertilizer with a predominant composition of nitrogen and gradual release, the stress of the summer heat will have depleted the soil of nitrogen, an element that must therefore be reintegrated with a constant subsequent release.

  • Fertilize the lawn in winter

It is a fertilization that balances the nutrients present in the soil, mainly based on potassium, which prepares the lawn for the winter cold and vegetative rest. A gradual release lawn fertilizer is used which, in addition to potassium, contains a significant part of nitrogen. Potassium has a positive action on the neck of the plants, which becomes more resistant to cold thermal stress, in addition to prolonging the persistence of the color of the lawn during the first cold temperatures and the first frosts.

For spring and autumn, a high-quality fertilizer of both a mineral and organic nature with a predominance of nitrogen is ideal, perfect for accompanying vegetative growth.

For summer and winter, use a quality organic, vegetable, and mineral fertilizer, composed mainly of potassium, to help the lawn manage heat stress.

Biostimulants for the lawn

Biostimulant treatments, based on specific biostimulant products for lawns, are not mandatory but are recommended: their use has spread enormously due to the benefits they bring to the health of the lawn and the effectiveness of fertilization.

They are part of a fertilization plan, integrating the granular fertilizers of the lawn. These are natural liquid products that, distributed together with fertilization, increase the benefits and make the lawn fertilizer much more effective.

The advantages of integrating fertilization with biostimulants for lawns are numerous:

  • Greater absorption of the nutritional elements provided by fertilization
  • The soil feeds better and more efficiently
  • Improved vegetative activity and turf respiration
  • Stimulation of photosynthesis processes
  • Greater resistance to thermal stress and heat shock
  • pH regulation

How to fertilize the lawn?

In order to fertilize well, in addition to choosing a professional, season-specific, slow-release lawn fertilizer, we need to know how to fertilize the lawn correctly. The fertilizer must be distributed evenly, otherwise, we will have more leafy portions of the lawn and others that are less green or worse, dry.

Another risk of fertilization that is not homogeneous is « over-fertilization “, which can burn the grass.

The amount of nitrogen, phosphorus, potassium, and microelements to distribute varies greatly depending on the type of grass and the type of soil on which it grows (sandy, loamy, acid, alkaline, etc.).

To determine the correct amount to apply, specific soil analysis and a consequent correction and fertilization plan are necessary.

But if you do not have the means to do so (like most mortals), as a general rule it is recommended to read the technical data sheets of each lawn fertilizer where the quantities per square meter are always indicated. For high-quality professional fertilizers, the amounts vary from 20 to 40 grams per square meter, for low-quality fertilizers higher amounts are required.

If our lawn is small, we can fertilize the lawn manually, paying special attention to distributing the right amount per square meter.

The best method to fertilize the lawn is to do it using special machines, fertilizer spreaders, these are usually equipped with levers that allow the amount of product to be distributed to be regulated, in addition to the direction.

Another advantage of fertilizer spreaders is that they can also be used for other lawn care and landscaping operations, such as lawn seed or as a salt spreader.

For more information regarding lawn seed or lawn fertilizer, you can contact us freely.

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