4 Steps to Use a Foliar Fertilizer

Contents

   – Focus on foliar fertilizer

   – Step 1: When to use a foliar fertilizer?

   – Step 2: Choose the right time to apply foliar fertilizer

   – Step 3: Respect the dose to use

   – Step 4: Apply foliar fertilizer

Foliar fertilizer is a liquid or water-soluble fertilizer sprayed on a plant’s foliage (vegetable, tree, flowering plant, lawn or houseplant).

You can make foliar fertilizers from chemical and natural products (algae, fish…). Slurries or decoctions of plants are very often administered in this way.

Here is a step-by-step explanation of everything you need to know to use a foliar fertilizer.

Focus on foliar fertilizer

The stomata assimilate the nutrients delivered by a foliar fertilizer. The advantage is that the plant assimilates foliar fertilizer very quickly, so it is an ideal form of administration for a “boost” treatment.

Garden centers offer specific foliar fertilizer formulas for different types of use, but you can easily make excellent plant slurries and decoctions that play the same role.

Good to know: Foliar fertilizer has become a generic term that designates a proper fertilizer for fertilizing purposes and a product sprayed on the foliage of plants to help them fight certain diseases or insects.

1. When to use a foliar fertilizer?

On which plants?

Foliar fertilizer is used:

   – in the vegetable garden, for vegetables;

   – in the orchard, for fruit trees;

   – in the ornamental garden for lawns and flowers;

   – on the balcony or indoors, for houseplants.

For what purpose?

You can use foliar fertilizer

   – As a “kick-start” fertilizer: quickly absorbed by the foliage, it can quickly restore vigour and colour to deficient or stressed plants. It is useful:

     ◦ When plants undergo difficult climatic conditions (heat, drought).

     ◦ When plants have undergone stress (repotting or transplanting houseplants).

     ◦ In case of deficiency of a particular nutrient (e.g. nitrogen).

   – In the preventive or curative treatment of a disease or insect attack: in this case, it is no longer strictly speaking fertilizer. However, most of the slurries and decoctions of plants have a dual action of fertilizer whiplash and treatment of diseases (cryptogamic diseases in particular) and insect attacks.

2. Choose the right time to apply foliar fertilizer

Choose the right time of day and weather conditions to apply foliar fertilizer.

   – In general, avoid very hot, sunny and dry periods, which favour stomatal closure.

   – Prefer early morning or evening, when cooler air favours the opening of stomata and allows better absorption of foliar fertilizer.

   – Take advantage of cloudy or stormy weather for the same reasons.

3. Respect the dose to use

   – For two reasons, avoid applying foliar fertilizer at rates that are too high:

     ◦ Foliage is a fragile plant organ that overly high doses of foliar fertilizer can burn.

     ◦ Doses that are too high can stress the plant and lead it to close its stomata, thus absorbing the fertilizer less well.

   – Regarding fertilizers bought in the market – organic or a fortiori chemical – scrupulously respect the doses indicated on the package.

   – For homemade slurries and decoctions, respect the dilutions indicated for spraying: they are often lower than the dilutions recommended when the fertilizer is administered by watering the plant.

For example, comfrey manure is diluted to 10% when used as a foot-drop fertilizer and 5% when sprayed as a foliar fertilizer.

4. Apply the foliar fertilizer

   – For a houseplant or balcony, use a spray bottle containing the fertilizer at the correct dilution.

   – To treat a larger area, pour the fertilizer at the correct dilution into your sprayer tank.

   – Spray or mist, especially at the growing points of plants, as young leaves absorb fertilizer better than older leaves.

Equipment needed to use a foliar fertilizer

Sprayer 

Pressure sprayer