How to give balcony granium (plargonium) fertilizer?

What fertilizer for balcony geraniums and how to administer them? Pelargoniums are greedy and need to be fertilized regularly in order to flower the planters abundantly… how, with what and when: precise explanations.

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Stunning balcony graniums

What do we ask of our balcony geranium pots (Pelargonium)? Let them grow lush and bloom in abundance until the cold weather sets inand all this with a rather small amount of land to keep these planters practical.

Large plants and ‘small’ containers, this is only possible by bringing food to pelargoniums, gradually, throughout the growing season. In effect, the zonal pelargoniums, lierres or large-flowered are greedy.

What type of mineral (chemical) fertilizer should be used to fertilize the balcony geranium?

The forms offertilizer mineral are multiple.

  • solid fertilizer in the form of grains, sticks or other: it is diluted with watering. They are perhaps more appropriate for people who are not diligent enough in their care of plants, or who do not like to play the little chemist by diluting the liquid fertilizer. Solid chemical fertilizer lasts a few weeks, but has the disadvantage of being concentrated in places. It is put towards the outside of the container, avoiding contact with the roots, as it can burn them. It dilutes with watering.

  • slow release fertilizer, in grains or cubes, is interesting, because it releases its fertilizer more gently (less problem linked to local overdose): the small grains slowly diffuse the fertilizer into the soil, and remain effective longer. However, for it to diffuse well, it must be buried underground: it must therefore either be pushed down in the case of the dice, or incorporated uniformly into the potting soil planting in the spring when repotting. The slow-release fertilizer is ideal for the forgetful.

  • liquid fertilizer is much better suited for balcony geraniums, concentrated evenly in the irrigation water and given in the right dosage, there is no risk of burning the plant. In addition, the geranium’s response to fertilization is rapid. On the other hand, it must be administered regularly throughout the growth period of the pelargonium. Dilute a measuring cap per liter of water in a watering can is ultimately easy, you just need to know the capacity of your watering can or measure the amount of water you put in it with a measuring cup. The main thing is to never overdose.

What kind of mineral fertilizer to use for balcony geraniums?

Read labels

Mineral fertilizer is defined by its main components NPKin addition to trace elements:

  • nitrogen N helps to grow greenery. It is favorable to stems and leaves.
  • phosphorus P solidifies the tissues and contributes to the development of the roots.
  • le potassium K promotes flowering.

Although these 3 elements are essential, we will understand that too much nitrogen benefits the development of the leaves to the detriment of the flowers. Or a geranium, we expect it to flower. Whatever the type of fertilizer (solid or liquid), we will choose a fertilizer with more potassium K than nitrogen N: example NPK 6.12.18, NPK 4 6 7, NPK 6 7 10 (note that on the first example, the dosage is stronger.)

A high proportion of potassium in a fertilizer does not only exist in geranium fertilizers and reading the labels often helps to avoid redundant purchases. So other types of fertilizers can match, including some that may already be in your home.

You can use :

  • flower plant fertilizer
  • fertilizer for fruit trees
  • fertilizer for tomatoes
  • fertilizer for roses (but be careful, it is often more concentrated, if the K proportion exceeds 18, dilute more than what is recommended (half a dose per liter for example).

Play around with liquid fertilizer dosages for even better results.

A small geranium makes few flowers, a large geranium makes many more inflorescences.

If you have purchased a young balcony geranium that is not very developed, it may benefit from only developing stems and leaves during April/May before starting to flower again.

So before administering the fertilizer for the flowers, you can booster with green plant fertilizer (more Nitrogen N and Phosphorus P than Potassium K) for a few weeks for it to grow first, then only then switch to flower fertilizer.

Season and periodicity: when should you give your geranium fertilizer?

Fertilizer applications are effective only during the growing season, i.e. from April. If you keep your geraniums in winter, they are in a dormant period and should not be fertilized.

Solid fertilizers are given at the start of the season. Ordinary solid fertilizer (grain) can then be given in small quantities (a few grains per plant) every month. Slow release fertilizers are administered when repotting, or pushed into the ground at the start of the season. A second intake in summer is often useful. You can then push them into the ground or cover them with a little new potting soil.

Liquid fertilizers are administered from April, at the rate of a contribution every 10 or 14 days. Geranium should be watered as soon as the top half of the soil is dry.

On the other hand, be careful if the whole mass of the earth is dry: the nutrient liquid can either burn the roots which will reinflate too quickly with this salt solution, or pass through the cracks too quickly without soaking the earth. It is good to moisten the pelargonium soil evenly first before watering immediately afterwards with the fertilizer solution.

For other types of Pelargonium, collection pelargoniums, xerophytes or scented geraniums.

The fragrant pelargoniums (rich in essential oils) such as rose geraniums, citronella… or very xerophytes do not have the same needs as balcony pelargoniums; they will be fertilized like cacti. Indeed, boosting their growth too much reduces the production of essential oils in scented geraniums and weakens collection pelargoniums.

Organic, chemical-free fertilization of balcony geraniums

It exists various organic and natural fertilizers for ready-made geraniums on the market: based on seaweed, plant manure, manure (manure is also considered to be of plant origin, because it comes from digested plant debris and straw).

These remarkable organic fertilizers not only play on the nutrient supply of plant origin, but also have a positive effect on the life of the soil, in particular the maintenance of the rhizosphere. The rhizosphere (what lives around the roots) will help the geranium to grow, defend itself against diseases, and optimize fertilization.

Hen manure is the closest to the necessary NPK dosage and any potassium deficits (element that promotes flowering) can be remedied with a little wood ash (barbecue without accelerator).

Some organic fertilizers are even already enriched with microrrhizal fungi. If you go for organic, stay there, because the chemical fertilizer becomes antagonistic to the bacteria and fungi in the soil.

The natural fertilization of the geranium: it is first a repotting in the rules.

The first organic fertilizer is good soil (without chemical fertilizer) rich in organic matter.

Then, to prevent it from drying out too much, it will be necessary if possible use larger planters or pots where the plants have more soil. The ‘organic’ geraniums will have more roots, and therefore more exchange surface. These geraniums will generally be very hardy.

The compost will be if possible mixed with a little garden soil (entirely or only on the lower half of the planter) then towards the bottom of the planter we add some decomposed manure (brown gold or chicken manure pellets).

Garden soil prevents the growing mixture from drying out too quickly: too much drought puts the microbiology of the soil on hold, or even reduces it drastically. Garden soil also provides some trace elements as well as a whole range of micro-organisms, bacteria and symbiotic fungi, useful for geranium.

Pelargonium grown in the ground

If grown in open ground, geranium, as far as possible, should not be fertilized with mineral (chemical) fertilizer. Firstly, chemical fertilizer disrupts soil biologybut in addition, mineral fertilizers are often washed away very quickly by watering or rain, so you have to put more in to see the effect.

Le leaching diverts the fertilizer into the runoff water which goes into the river or sinks down to the water table, it is therefore polluting.

Furthermore, the fertilizers administered near the geranium limit the development of symbiotic micro-organisms, they will also prevent it from making long roots (why develop long roots if the nutrients are within reach, without effort); it will then be more sensitive to drought.

The fertilization of pelargonium grown in the ground will be done especially by taking care of its plantation, and boosted with the help of natural fertilizer: a good amount of compost et a little chicken manure or seaweed in the bottom of the planting hole. Then some wood fire ashes mixed with the surface soil.

Source: Au Jardin, conseils en jardinage by

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