HOW TO GROW STRAWBERRIES IN A GREENHOUSE
Strawberries are bright red, sweet, and juicy fruits grown for direct consumption or addition to other foods, e.g., pies. They are high-valuable crops grown for export or local markets.
Questions to ask your self before planting strawberries in a greenhouse ?
- Why should I grow my strawberries in a greenhouse?
- How to grow strawberries in a greenhouse?
Experienced strawberry farmers can effortlessly know the answer to these two questions, but it will be challenging for new farmers. This article aims at helping new farmers know about strawberry farming in greenhouses and where to acquire the necessary help.
Varieties of strawberries grown.
The type of strawberry grown in Kenya is the day-neutral type. These strawberries produce fruits as long as there is light, meaning they are not affected by short and long days. Day-neutral strawberries go dormant during winter, and Kenya, being in the tropics, doesn’t experience winter. The lack of winter in the tropics means day-neutral strawberries can produce fruits throughout the year.
There are various varieties of day-neutral strawberries you can grow in Kenya. These types include;
- Chandler variety – these types of strawberries have high yields with big fruits. They take about 62 to 75 days to produce fruits with firm skin and quality flavour.
- Pajaro – they grow fast and produce fruits that are big and with good flavour.
- Fern – The fern variety is a high-volume variety with large light-coloured fruits.
- Selvia – these strawberries are small-sized compared to other types. They have good flavour and bright colours.
- Aiko – the fruits of the Aiko variety are large, long, and conical. They are pale red and are a bit sweet. The main advantage of this variety is its large harvest and resistance to transport.
- San Andreas – These strawberries produce fruits during the whole year. The plant is resistant to most common diseases and makes dark red fruits. To maintain high yields in the plants, you must cut the many runners. In Kenya, they are popular around Nyeri.
- Douglas – These plants mature very early and have clear foliage. The fruits produced are orange-red, with firm flesh, quality flavour, and long conical shape.
Environmental conditions for strawberry growth
Strawberries grow in areas having temperatures ranging from 200C to 300C. In regions having temperatures above 300C, flowering and fruit production will be significantly affected. The pH of the soil needs to be between 5.5 and 6.5. Soils with high pH will affect iron intake, reducing the final yields. Strawberries are reactive to salinity during transplanting. High levels of alkalinity in the ground will result in the plant leaves yellowing. You should check the salinity and alkalinity levels for optimum yields. Strawberries need areas with adequate amounts of water.
Factors to consider when growing strawberries
Factors to consider when growing strawberries in greenhouses include;
Strawberries require about 36 to 45 cm of water to cater to plants’ needs for the entire growing season. The plants have shallow roots meaning you have to apply adequate water due to evaporation. The best way to supply water to the strawberries is by using drip irrigation. Drip irrigation helps in water conservation by providing only the required quantities. Too much water will result in the spread of diseases, whereas too little water will lead to water stress, reducing the yields. The advantage of using drip irrigation is that the system can also supply nutrients in appropriate amounts to the plants.
Strawberries do well in a variety of soils. The soils need to be deep, well-drained and have high organic matter. Clay soils are heavy soils with good water retention capabilities. However, using clay soils in strawberry farming is not advisable since there will be waterlogging that can spread diseases. Using coarse sandy soils will lead to high irrigation and fertiliser application expenses—the high-cost results from the high infiltration rates and infertility of sandy soils.
It would be best to have good surface drainage to avoid water accumulating on the farm. Strawberries are sensitive to moisture, and a lot of water results in diseases and the death of the plants. In the case of strawberry farming in areas with poor infiltrating soils, it can help to raise the beds. The height of the bed should be a minimum of 15 cm.
The soil pH
Strawberries grow well in soils that are a bit acidic, having a pH of about 5.0 to 7.0. Before embarking on strawberry farming, you should first know the pH of the soil on your farm. Institutions such as Kenya Agricultural and Livestock Research Organisation (KALRO) carry out soil tests and give you a complete soil analysis. The soil sample should be dry and have stayed long without fertiliser application. At times the researchers can ask you about the plant history on the farm. So, it is best to keep that in mind.
The soil analysis report shows a complete review of the composition of nutrients in the soil and the pH. Using this report, an agronomist can easily advise you on what fertilisers to use to ensure optimal soil growing conditions. You can correct too low pH in the earth using lime and high pH using green manure or acidic fertilizers.
These plants need a gentle slope to allow water to flow out of the farm area. At Eunidrip, we recommend a gradient of less than 10%. Growing strawberries on slopes of more than 10% will lead to erosion, with some plants being uprooted or even buried. The shallow roots of the strawberries make them very easy to remove from the ground. You can still grow strawberries on steep slopes if you have no choice. Your plants will be okay as long as you plant them in rows across the hill and have a wide row width.
Sunlight is an essential requirement for strawberry growth on farms. Strawberries need at least six hours of sunshine in a day for high yields. Whether growing your strawberries on the open field or in a greenhouse, you should ensure no large trees nearby can block the sun. Placing your strawberry farm away from trees also reduces water and nutrient competition. The sunlight also helps in giving the strawberries their deep red colour.
The strawberry variety
There are various varieties of strawberries available, with each variety having its pros and cons. Before engaging in strawberry farming, you should consult on the best variety to grow within the specified region. The variety you choose should also be certified to avoid diseases on the farm.
It would be best if you do not plant strawberries in areas where certain types of plants have been grown in the previous four years, i.e., potatoes, carrots, tomatoes, eggplants, alfalfa, and beans. These soils contain diseases and pests that can attack your strawberries. It would help if you first fumigated the earth to kill the pests and disease agents using such soils.
Why choose to grow strawberries in greenhouses?
Many farmers know that the environment greatly affects the outcome of their crops. When growing crops on the farm, it can be difficult to control factors such as temperature and humidity. Strawberries are high-value crops, and you need to ensure maximum care to reap maximum rewards. The use of a greenhouse gives you more control of the growing environment of the strawberries. In a greenhouse, you can control the temperatures, humidity, water loss, quality of light and pests and diseases. It reduces the risks involved in farming. At Eunidrip, we deal with greenhouses and we can also teach you how to grow strawberries in a greenhouse.
Strawberry farming and practices
Some of the strawberry farming practices done in the greenhouse include:
Propagation refers to ways in which new strawberry plants are formed. You can propagate strawberries using three methods. These methods are;
- Plant division – this is achieved using the crown of the strawberry. The crown is a short and thick part of the strawberry that emerges from the soil. It is usually a few millimetres long and contains a lot of roots. The crown emerges naturally, or you can induce it by pruning. This method is labour intensive and requires technical skills. If you don’t do it carefully, you can risk killing the parent plant.
- Seed propagation – seed propagation involves planting strawberry seeds. It would be best if you did not use the seeds from a purchased strawberry because low-quality plants will emerge. The low-quality plants are a result of crossbreeding. You will need to purchase certified seeds from agro-vets to propagate using seeds. Certified seeds reduce the risk of disease spread and ensure high-quality plants.
- Propagation by runners – runners are stolons that protrude from the strawberry stem. They grow in various directions, and when the nodes touch nutritious soils, new roots start to develop at that point. As the roots develop and the plant anchors itself properly on the soil, you can cut the runner separating the new plant from the parent plant. Propagation by runners produces an identical plant to the parent plant. This method is the easiest method of propagation than the others.
Before planting the strawberries, you should add adequate organic matter to the soil. If crops such as tomatoes and potatoes were grown before, you fumigate the soil before planting anything. You can plant strawberries either on raised beds or flatbeds. The two planting systems used for flatbeds are hill rows or matted rows. The matted system involves planting the strawberries 60 cm apart in a row and 120 cm between the rows and allowing the runners to spread and grow within the rows. This method produces a lot of fruits even though they are of poor quality.
The hill row system involves the removal of runners from the planted strawberries. This ensures the parent crop receives adequate nutrients and can produce large fruits of high quality. The strawberries in hill row systems sprout multiple crowns increasing the number of fruits produced. Plant spacing in the hill row system is 30 cm between the plants and 60 cm between the rows.
The growing point of strawberries is near the soil surface. Placing the plants too deep can result in the rotting of the crown. It would help if you irrigated the plants after immediately planting to avoid killing off the new plants.
You can mulch strawberries using organic mulch or plastic mulch. Organic mulch involves using plant materials like straws, leaves, cut grass, etc. The use of organic mulch requires frequent replenishment as it decomposes with time. At Eunidrip, we recommend using plastic mulch in your greenhouse, especially for long-term use. The combination of plastic mulch and drip irrigation in greenhouse strawberry farming ensures minimal water use and optimum growing conditions for your plants. The advantages of using plastic mulch are;
- Controlled weed growth
- Reduced water losses by evaporation
- Increased crop yields
- Reduced soil erosion
- Improved crop health
- Soil temperature control
Pest and disease management
Pest and diseases are the major causes of poor-quality strawberries. Examples of pests affecting strawberries are aphids, birds, crown borers, cutworms, slugs and snails, wireworms, spider mites, and tarnished plant bugs. The common diseases affecting strawberries include powdery mildew, Leathery rot, red root rot, grey mould, fungal leaf spots, and blossom-end rots.
Strawberries achieve pollination by using wind, animals, or hand pollination. When carrying out greenhouse strawberry farming, it is best to place a hive near the greenhouse to permit pollination by bees. This method is much more effective than hand pollination. Some of the benefits of strawberry pollination include:
- There is an increase in yields.
- Cross-pollination reduces deformations in the plants.
- Pollination by bees results in more appealing fruits.
- Strawberries from plants that have undergone cross-pollination are much larger than those which self-pollinate.
Strawberries need protection from rainfall, slugs, and birds. Birds love the sweet taste of the fruits, whereas the slugs enjoy feeding on the strawberry leaves. Growing your strawberries in the greenhouse helps control these three problems. Rainfall causes the leaves on the plants to drop. In the case of field farming, you can use bird nets and copper ribbons to protect against birds and snails, respectively.
Strawberry greenhouse automation
Greenhouse automation is useful when it comes to commercial strawberry farming. In an automatic greenhouse, you can control the temperature, humidity, water, nutrients, carbon dioxide, and pests.
Temperature control inside a strawberry greenhouse is achievable using thermometers to detect the temperature changes in the greenhouse. A computing system then controls the temperature using a heating or cooling system within the set range. It would be best to keep the temperature between 200C and 300C when farming strawberries. Plastic mulch helps control the soil temperature.
When farming strawberries, you use drip irrigation in the greenhouse to ensure an efficient water supply to the plants. Automatic greenhouses use timers to control the amount of water supplied to the plants. The timers can be mechanical, electronic or hybrid. Using timers, you can set when to start the irrigation and stop after how long. Sensors can help in more accurate control of the amount of water supplied. The sensors can detect the amount of water in the soil and initiate irrigation when the water levels fall below the set threshold.
The Humidity refers to the amount of water vapour in the greenhouse environment. Humidity affects the rate of water loss in the plants. High humidity levels, especially at night, will result in gaseous water condensing on the greenhouse material and dropping to the ground as water droplets. Strawberries are very water-sensitive, and these droplets can result in the development of diseases. In automated greenhouses, you achieve humidity control using the ventilation, humidifying and dehumidifying systems. Sensors detect humidity levels in the greenhouse, and when they go beyond the set values, either of the three systems is activated.
Strawberries prefer slightly acidic soils. Excessive use of fertilisers can result in the pH of the soil going up above 7.0 or below 5.0 depending on the type of fertiliser. Other effects of excessive use of fertilisers include leaching of nutrients, pollution of water sources, chemical burning of crops and mineral depletion in the soil. In strawberry greenhouse farming, you can achieve controlled fertiliser application using a fertigation system. The fertigation system is an arrangement that enables diluted fertiliser to be delivered to the plants using irrigation. Sensors in the soil monitor the substrate quantities in the soil in automated greenhouses. The sensor alerts the computer when the substrate quantities go below the set quantity. The computer, in turn, activates the fertigation system, which delivers the diluted nutrients to the plants.
Strawberries are fruits that have a high value. They are mostly grown for export and need to comply with the phytosanitary requirements of the exporting country. Pest control in a greenhouse is much easier than in the field. Insect nets help prevent insects from entering the greenhouse. Pesticide application inside the greenhouse is also much more effective than field application. Pest control in automated greenhouses uses cameras to detect the presence of pests or signs of pest infestation. When they are detected, you are alerted, and you can proceed with the necessary measures.
Carbon dioxide is an important gas that helps plants in photosynthesis and development. To improve the yield of strawberries, you can add a carbon dioxide system in the greenhouse. You can use sensors to measure the carbon dioxide levels in the greenhouse and alert the computer when to add more gas. Burning fossil fuels and using liquid carbon dioxide are the two main ways of adding carbon dioxide to your greenhouse. Burning fossil fuels is a cheap method of the two, but you risk damaging your plants. Liquid carbon dioxide is expensive but the safest method.
What are the advantages of growing strawberries in greenhouses?
The following are the advantages of growing strawberries in a greenhouse:
- Pest and disease control
- Efficient water usage
- Reduced labour costs
- High quantity and quality yields
- Plant protection against the elements like the wind.
- Reduces the risks of farming.
Eunidrip Irrigation Systems as a greenhouse designer, supplier and installer.
We are a reputable greenhouse equipment supplier in Kenya. We design, supply and carry out the installation of greenhouses all over Kenya. Also, we have a professional team available to answer your questions concerning strawberry greenhouses: What type of materials to use? Which row arrangement should I use? Which type of irrigation can I use? How to grow strawberries in a greenhouse?
Apart from greenhouse construction, we also deal with all irrigation equipment supply and installation, shade house construction, borehole drilling, water harvesting structures and dam lining.
Why choose Eunidrip Irrigation Systems.
We are amongst the major irrigation and equipment suppliers in the country. Our product line keeps evolving with time, ensuring we offer the best solutions to the farmers. We have well-established clients, and we can transport equipment anywhere within the country. We strive to ensure we continue providing high-quality services, and value our customers’ feedback. Our website is easy to navigate, and you can select the necessary equipment you need.
Our prices are customer-friendly, and you can also contact us on 0728163329 or visit our shop at George Morara Road, Nakuru town.