Ideal fertiliser for fruits, vegetables

Imelda Akinyi arranges fruits at her stall in Kogelo on July 14, 2015. [Reuters]

 

Vegetables and fruits need essential minerals and nutrients to grow healthy and strong. During growth, plants utilize nutrients from the soil to be replenished by the application of fertilizers.

However, the wrong choice of fertilizer can be costly to farmers and can affect the overall growth of the crop. Poor growth can significantly reduce the yields.

Today’s article highlights the considerations to make while choosing the fertilizer for fruits and vegetables.

Soil test

Soil tests for vegetable and fruit production involve the evaluation of plant nutrient availability in soils.

Information about the nutrient status of the soil will inform the type of fertilizer required to replenish the deficient nutrients.

Regular or standard soil analysis for pH, nitrogen, phosphorus, potassium, calcium, magnesium, sodium, sulfur, and salinity should be adequate for most garden fertility needs.

However, tests also are available for the micro-nutrients zinc, iron, copper, manganese, and boron.

Should any deficiency of the nutrients be suspected, a request for soil analysis is conducted to address the shortfall.

After the soil test is done, your report will give you the composition of nutrients in your soil, and you can match your fertilizer to what is missing. Extension officers could recommend liming for acidic soils.

Vegetable plants take up nutrients continuously. It is beneficial to provide them with a balance of nutrients throughout their growth.

At times, the most efficient way to achieve this is to apply slow-release fertilizers designed to release nutrients over a relatively long time.

Slow-release fertilizers contain one or more plant essential elements.

They can be categorised by how these elements are released. The major types of nutrients are released from materials that: dissolve slowly, from which microorganisms release the nitrogen; and, from granular materials with membranes made of resin or sulfur that controls the rate of nutrient release from the granules into the soil.

First, what type of soil do you have? Is it clay, sand, or loam? Soil type dictates the frequency of fertilizer application.

Sandy soils require more frequent applications and lower amounts of nitrogen and other nutrients than do clay-type soils.

Other factors affecting application frequency include the crop being grown and its intended use, the frequency and amount of nitrogen or water applied, and type of fertilizer used, and its release rate.

The crop influences timing and frequency of application because some crops are heavier feeders on some nutrients than others.

A general rule of thumb is that nitrogen is for leafy top growth; phosphorus is for root and fruit production; and potassium is for cold hardiness, disease resistance, drought tolerance, and general durability.

Proper use of nutrients can control plant growth, rate, and character. Nitrogen is the most critical nutrient in this regard.

If tomatoes are fertilized too heavily with nitrogen, the plant may be all vines and no fruit.

Understand the numbers on the bag

Organic fertilisers are labeled with the percentage concentration of nutrients. These are referred to as the NPK ratio, which stands for Nitrogen, Phosphorous, and Potassium. In a 6-12-0 formula, for example, there is 6 per cent Nitrogen, 12 per cent Phosphorous, and 0 per cent Potassium.

It’s also a good idea to consider other types of nutrients that you may need. Fertilizers have all sorts of micronutrients and minerals that can replenish other missing pieces of your soil.

Fertiliser Form

Fertilizers come in either liquid or dry forms. Dry fertilizers are slower to release and last over a longer period. They are good when you need general plant maintenance and are rebuilding nutrients directly in the soil.

Liquid fertilizers are faster acting and are better when your plants need a boost. Foliar-applied nutrients are rapidly absorbed and used by the plant. Absorption begins within minutes after application, and with most nutrients, it is completed within 1 to 2 days. Foliar fertilization can supplement soil fertilization at a critical time for the plant but not a substitute.


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