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Fertilizer Types for Durian Trees and How I Use It (With Photos)

CIRP, wood vinegar, neem oil, liquid fertilizer, soil amendment, plant food, foliar spray

Durian saplings and adult trees need feeding and they do feed a lot. Here I progressively discuss on my initial fertilization and soil amendment regime including adjustments that I'll make from time to time.

I won't bore you to death with all the theoretical and scientific mumbo-jambo - this is not a horticultural course. I'll discuss on what I practically do and the fertilizers that I personally use for my own plants for it to grow vigorously. Obviously young saplings will need a different feeding regime compared to adult durian trees.

Soil amendments are different from fertilizers in a way that it does not feed the plants with nutrients -traces maybe but its main function is to amend or condition the soil parameters and its mechanics. Another purpose of soil amendments is that it feeds the microbe and lifeforms in the soil. I will discussed about soil amendments in another post.

Initial fertilization and periodic fertilization is done prior, during planting and after planting. For me to discuss this topic in an organized manner, I would categorize fertilizer types to be in either 1 of these 3 categories:

1. Granular Fertilizers

2. Water Soluble Fertilizers

3. Foliar Fertilizers

Granular Fertilizers

These are normally in granular or coarse pellet forms and comes in various nutrient content or N-P-K configurations. These are what we call compound fertilizers. Single fertilizers on the other hand as an example is urea which is normally used for lawn fertilizer.

The lowest ranges of compound granular fertilizers are 5-5-5 and 8-8-8 while the higher nutrient contents are 18-18-18, with fertilizers specifically for flowering and fruit bearing has the last number in excess of 20. Most of these type of fertilizers are chemical based but some a semi-organic.

I periodically use the semi-organic Soya-Fish type with an N-P-K rating of 8-8-8-8(TE) shown below. In case you don't know 'TE' stands for 'trace elements'.

Organic fertilizers that I use are processed chicken manure (powder type with lesser odor than the granular type).

Onset of the raining season is usually the most suitable time to apply granular form fertilizers although during low precipitation the same could be applied regardless, the effects to the trees would be seen slower.

During drier months I would apply foliar sprays more which I will discuss in the below paragraphs.

Water Soluble Fertilizers

Water soluble fertilizers are either used for fertigation (hydroponics or drip/sprinkler irrigation application methods). It can also be applied as foliar sprays.

An example of water soluble fertilizers that I apply as foliar spray is MKP or monopotassium-phosphate.

MKP is basically a type of salt and it does looks like salt. The brand I used is Ag-Tech and its imported from Europe. With an N-P-K rating of 0-52-34, this fertilizer benefit the plant by promoting root and shoot growth including better drought resistance due to efficient water uptake.

Although I normally apply MKP as a foliar sprays, sometimes I will apply it as a soil drench for my durian saplings.

The concentration that I currently prepare for my saplings is 2.0 EC (electrical conductivity), measured with an EC meter. Trees which are 1 year old will be prepared with a 4.5 EC dilution.

Dilution with distilled water is the best since distilled water is 0 EC while tap water will give some measurement due to dissolved impurities.

I will illustrate in practical on how to prepare the MKP solution. Prior to dilution of the salt, one must decide on how much is the concentration required depending on the size of the sapling.

Another water soluble fertilizer and is applied as foliar spray is potassium nitrate or KNO3. I have never actually bought or used this fertilizer.

Some growers would mix both KNO3 and MKP to form a complete solution containing all the NPK major nutrients in a single spray application but I don't do it because I never bought KNO3 and if I did, I risk burning the plants since the concentration of potassium in the solution would be 80.

Foliar Fertilizers

These are fertilizers which is bought in bottles of concentrated liquid forms which the grower would then dilute according to the instruction label.

It could also be liquid organic fertilizers (home-made or otherwise) such as fish amino acid, plant booster, seaweed, EM or others. Foliar sprays add another dimension in plant feeding meaning that not just the plant gets it feed via roots but also via the leaves and branches.

Foliar sprays that I personally use for my plants as below:

1. Wood vinegar

2. Mono-potassium phosphate or MKP

3. Proprietary foliar fertilizer (Fastgrow)

4. Plant booster (homemade)

5. Fish Amino Acid (homemade)

Wood vinegar is not exactly a fertilizer, it's more of a plant vitamin. Wood vinegar is produced by burning wood or bamboo in a kiln whereby the condensate from the steam or smoke is gathered. The condensate is wood vinegar.

Used for more than 100 years in Japan for agricultural and livestock farming purposes, wood vinegar acts as a growth hormone, increases plant immunity and has fungicidal properties.

I won't delve deeper into the history of wood vinegar in agriculture since it could be searched in detailed articles on Google.

The way I use wood vinegar is by making a 1:300 dilution with water and spraying the solution below the plant leaves. The underside of leaves is where most of the stomata is located. Depending on how much solution I've prepped, I will spray the top surface of leaves if I have enough wood vinegar solution.

Fastgrow Green is a proprietary liquid concentrated fertilizer manufactured by a local based company Fastgrow Fertilizer Sdn. Bhd. Originally researched and produced for palm oil trees and is now into fruit trees and vegetable fertilizer market.

What makes Fastgrow Green special is it applies human cosmetic technology for which the liquid fertilizer could be absorbed through the tree trunks and branches.

I have personally use this fertilizer for about 2 years now and it does promote new shoot growth of my durian saplings. Until the time of this post writing I haven't finish the 1 liter bottle that I purchased almost 2 years ago.

Plant booster is not a fertilizer but a natural growth enhancer. The standard recipe for making plant booster was introduced by the Agricultural Department. It is a cloudy orange liquid derived from fermentation process. Method for making plant booster is discussed in this post.

Ingredients for making plant booster
Ingredients for making plant booster

Spray application of the plant booster is done in the early morning, as with other foliar sprays.

As with plant booster, fish amino acid or FAA is a growth enhancer and stimulant. It can be made at home and could also be store bought. The recipe and method for making it at home is discussed here.

Application by spraying for both plant booster and FAA is once a week. More frequent application does not hurt but personally I'd use the time and energy for other foliar applications.

Foliar Spray Application Time

It is good practice and recommended by the Agricultural Department that foliar sprays be applied during early morning when the leaves are wet with morning dew. In Peninsular Malaysia this would mean ideal spraying time would be between 7.00 am until 9.00 am.

The reason for this is that the leaves surface tension in terms of wettability is better. Another reason is that the leaves stomata are fully open for which the foliar fertilizers could be quickly and efficiently be absorbed by the leaves through the stomata and into the plant's system.

At 9.00 am the sun is already shining brightly and the leaves starts to get hot. This would make the stomata opening to start shrinking. It's basically the plant's physiological mechanism to reduce water evaporation.

At this time as well the evaporation of the foliar spray starts to accelerate due to the increased surface temperature of the leaves which makes it a wastage of fertilizer.

I would like to note as well that the highest number of leaf stomata is on the backside of most plant leaves and not on the top of the leaf. Having said this, if the volume of the foliar spray solution is limited due to certain reasons by the grower, then the backside of the leaves are to be sprayed first.

Fertilization Considerations

Fertilizer cost is the second most highest cost after manpower cost in any farm or orchard. For a durian grower, a balance must be made between purchasing high-end NPK fertilizers against the more affordable organic option.

In most cases, both chemical and organics are used in rotation with 60% chemical and 40% organics while some growers who pursue organic certifications would attempt to make the figure 30% chemical and 70% organics.

When attempting to use more organics, new growers should understand that the volume or weight of organic fertilizers consumed in the duration of let's say a year would be more than the chemical NPK compound option for the same result on the trees.

In the long run, applying organic fertilizers and soil amendments will enriched the soil and not just feeding the trees.

NPK compound fertilizer comes in various specifications and prices but the best fertilizers are mostly imported either from Europe, Scandinavia or Japan. Locally made fertilizers are more fairly priced.

Fertilizer brands such as Yaramila, Zeenex and Novatec granular fertilizers are considered high-end types which is sold at prices in excess of MYR120 for a 20kg pack.

It has to be noted for the benefit of new durian growers that the durian tree is sensitive to chloride and prefers suphate-of-potash for potassium (SOP) against the cheaper muriate-of-potash (MOP) compound. As a rule of thumb, please be aware of the chloride presence prior to purchasing any fertilizers.

Durian tree growth and fruiting shall have better growth, fruit yield and flesh taste if applied with NPK compound granular fertilizers with presence of trace elements or micro-nutrients.

Personally, in the early stages of my orchard I'm applying 60% chemical and 40% organics due to the immediate fertilization requirement as a result of my soil test which is dangerously low in nutrients.

This ratio will be reduced gradually to be more organic heavy in the years to come.

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1 Comment

Abdullah Reed
Abdullah Reed
Mar 21, 2023

Thanks for sharing these details.

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