Sunday December 17 2017

Using soilless media to grow vegetables

Akuttu and wife spread the threshed cassava on

Akuttu and wife spread the threshed cassava on a polythene bag on the mesh to dry. Photo Simon Emwamu 

By Beatrice Nakibuuka

Even with the healthiest soils, it is still possible to find pests and other pathogens that attack crops and likely to lower your crop yields.
Soilless growing media have been proven to be sterile and free from pathogens that are soil-borne and applicable for urban farmers who grow plants on rooftops and containers.
In urban horticulture, almost all containerised plants are grown without any soil (hydroponics).
Soilless media, as the name suggests does not include soil; plants are grown in different organic materials. Soilless media are getting more popular.
According to Winfred Opio, an agronomist at Naro, for a good growing media, it is necessary that the plant gets a healthy balance of water and air.
The soil sometimes has harmful bacteria and fungi so the crops are prone to pests, weeds and soil-borne diseases.

How to make a soil-less media
Depending on the choice of crops you can prepare your own mix. A sterile soilless mix is made from organic components such as chicken waste (a combination of chicken droppings and coffee husks or sawdust after cleaning chicken houses) and organic household refuse that can easily decompose.
“You may add a small amount of fertiliser since the soilless mix does not have much fertility by itself. You may need to provide fertiliser from outside. The mixture is first left for in a place to decompose like you would make compost manure for about two to three weeks,” she says.
Decomposing this will help reduce the heat in the medium and break down the amount of urea in it because if used the way they are got from the chicken house, they are likely to burn up the plants.
Before planting, ensure that you lightly moisten the mix before filling the containers where you will plant the vegetables.
Do not pack the mix too tightly when planting and ensure that your media has enough water and moisture.
Water is transported through the growing medium into the roots and plant xylem towards the plant canopy where it eventually transpires into the atmosphere.
The continuous uptake of water is essential for the growth and survival of plants.
“This medium will surely provide a place for root structure to develop, give hydroponically-delivered nutrients maximum for root exposure, allow plenty of air space for healthy root structure and accelerate the growth of nutrient-absorbing root hairs for the vegetables,” says Opio.

Less labour needed
The soilless media gives you better control over irrigation and fertilisation.
This is because they have a high degree of water retention which will reduce the frequency which you will have to water your crops had they been planted in the soil.
Also you save yourself the burden of applying fertilisers in your garden and the burden that comes with mixing them.
“Weeds are time consuming and irritating but only present if you planted in soil. With the soilless media, you will not have to bother with weeds. Like weeds, getting rid of soils makes your plants less vulnerable to pests and diseases. The pests are very easy to control because most of these are usually soil-borne. This will reduce the amount of time and labour you would use to spray the plants with pesticides,” she remarks.

Small space needed
The soilless media is advantageous in a way that a farmer is able to achieve high yields in a limited area by applying a quality growing media. The same media can be used for about three consecutive seasons without break which may not be the case with soil-based plants.
“Because all that plants need are provided and maintained in a system, you can grow vegetables in your space. The roots of plants in the soilless media will not expand or spread out too much because the nutrients they would look for are readily available. This will enable you to grow your plants much close consequently making huge savings on space,” she remarks.

Faster growth rate
Since plants are placed in ideal conditions and provided with sufficient conditions of growth, the plants in soilless media grow faster because they do no waste energy searching for diluted nutrients in the soil. Instead, they shift all of their focus on growing and producing fruits.
“You can harvest about 10 tonnes of tomatoes from the backyard soilless garden,” explains Opio.

Climate control
Opio says, “With the soilless media, you will be able to beat the problem of climate change including - temperature, humidity, light intensification, the composition of the air because you can control the amount of water your plants require and can equally provide for them sufficiently. This will enable you grow crops throughout the year even during dry spells and will maximise your profits.”

Need for expertise
The procedure for making the media may not be simple and one may need prior knowledge and expertise especially in the composting process as under or over composting may affect the plants. Therefore, if a farmer wants to have the best results, they need to consult an expert for advice.

Frequent replacements
Soilless media has a productive lifespan of about one to two years, before the nutrients are exhausted and it needs to be replaced. Replacing may be hard especially if you do not have a permanent source of material to mix for the media. “Also, the farmer should be mindful about where they get their seeds from. This is because with the soilless media, if the seeds are disease-infested, it is very easy for the whole garden to get infected,” she says.