Strawberries are tasty, fun to grow, and fast to deliver

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Strawberries grow well in pots. Image by congerdisign from PixabayStrawberries grow well in pots. Image by congerdisign from PixabayStrawberries remain one of the most popular garden fruits and are relatively easy to grow, and if space is limited they can be grown vertically, in strawberry gutters, or in pots or special strawberry pots, as well as hanging baskets, enabling gardeners to produce large quantities of fruit from a very small area. One healthy plant can produce 500g or more of fruit per season, and a well-managed bed can remain productive for up to three years. Read all about strawberries below.

The genus ‘Fragaria’ to which strawberries belong contains more than 20 species of flowering plants, and like apples, pears, raspberries, and cherries, are members of the rose family (Rosaceae). Strawberries are low-growing leafy plants about 12 to 15cm tall with a spread of about 50 to 100cm,  and the beautiful white or pink flowers look just like little single roses.

Strawberry is the only fruit to carry its seeds on the outside, and the fleshy edible part of the plant is in fact not the fruit but rather the enlarged receptacle of the flower, while the visible seeds that dot the surface of the berry, called “achenes” are the ovaries, so technically each seed is a fruit. There are 200 seeds on the average strawberry, and since no two seeds are the same, each of these seeds has the genetic potential to become a new variety of strawberry. This is how plant breeders develop new varieties of strawberries.

A "straw of berries" Image by Lena Svensson from PixabayA "straw of berries" Image by Lena Svensson from PixabayIt is unclear where the name "strawberry" came from, but it is commonly believed to have derived from the Old English word “streawberige”, a reference to the habit of growing cultivated berries on a bed of straw, and when the berries were harvested they were also often strung on a straw blade and sold that way as a “straw of berries.” Still others think that the name comes from the word meaning “to strew,” because the plant’s runners stray in all directions and look as if they are strewn on the ground. The scientific name Fragaria refers to the sweet fragrance of the berries.

Wild strawberries grow on every continent except Africa, Australia and New Zealand. But you wouldn't want to eat most of them as they are generally really small and tasteless, and some aren't even red.

To fully understand the history of the wild strawberry and how it evolved into the modern strawberries we grow today we first need to understand about sex and strawberries. Researchers now know that strawberries have some of the youngest sex chromosomes among flowering plants and animals, and by ‘young’ on the evolutionary time scale they mean a few million years! And researchers have literally caught strawberries in the act of transitioning into two sexes.

Although separate sexes may seem fundamental to nature, like woman and man, hen and rooster, cow and bull, they’re an oddity in the world of plants. After all, finding a mate is tough when you’re rooted into one place! For this reason most flowering plants are hermaphrodites and contain both male and female sex organs. Only 6 percent have split into different sexes, but many of these two-sex plants like asparagus, papaya, hops, marijuana and some strawberries, are of great importance to humans.

Strawberry breeders now know that strawberry plants can have one of three reproductive functions: male, female, or hermaphrodite. Male plants bear flowers that produce pollen but cannot set fruit. Female plants produce fruit only if their flowers are pollinated, but cannot produce their own pollen.

Hermaphrodites contain both male and female functions that enable them to flower, self-pollinate, and bear fruit. Today, most garden varieties are hermaphrodite and many strawberry farmers prefer their plants to be hermaphroditic so they don’t have to plant more than one kind of strawberry in the same field in order to have any fruit to harvest.

Modern researchers gained even more insight into the mystery of the sexual differences in strawberries when they found that hermaphroditic strawberries evolved the ability to spawn single-sex offspring, and they documented how members of Fragaria virginiana become male or female depending on the combination of genes they inherit from a hermaphroditic parent.

Because strawberries grow wild on so many continents, the history of the strawberry and its uses is too vast to document here, but here are some highlights on the fascinating story of strawberries.

Wild Strawberry (Fragaria vesca) Image by Erik Karits from PixabayWild Strawberry (Fragaria vesca) Image by Erik Karits from PixabayThough wild strawberries are small and bland compared to the cultivated strawberries of current times, archaeologists have found wild strawberry seeds at Mesolithic, Neolithic, and Iron Age sites indicating that early man ate strawberries. However, strawberries have gone through periods of acceptance and contempt and are not reported to have been cultivated until the 14th century.

Wild strawberries were collected in the wild and used medicinally by the ancient Romans as far back as 230 BC, to cure anything from melancholy to kidney stones. In the first century A.D The Roman poets Virgil and Ovid mentioned the strawberry, but they referenced it as an ornamental, not as a food.

For a long time strawberries were held in contempt because of their association with snakes and other dangerous creatures. The strawberry's low growing habit spurred Virgil to warn children to look out for serpents lurking in the grass when picking the wild fruit, and this distain for strawberries because of their association with snakes and other dangerous creatures continued into the 12th century when Saint Hildegard of Germany declared the strawberry unfit for human consumption because it grew on the ground where snakes and toads could slither and crawl upon the fruits.

By the 1300’s strawberries finally started losing their bad reputation and gardeners in France were transplanting the wood strawberry (Fragaria vesca) from the wilderness into their gardens. In 1368 Charles V of France planted 1,200 strawberry plants in the gardens of the Louvre, and a few years later the Duke and Duchess if Burgundy planted thousands of plants at their Dijon estate.

In the early 15th century western European monks were using the wild strawberry in their illuminated manuscripts, and depictions of strawberry plants and fruit can be found in Italian, Flemish, German, and English art.  Strawberry designs were often carved onto altars and on the top of church and cathedral pillars to symbolise perfection and righteousness.

Thomas Wolsey, the cardinal and statesman who dominated the government of England's King Henry VIII from 1515 to 1529, introduced the concept of strawberries and cream to the court where it quickly gained popularity. In the 1800's a prominent figure in Napoleon’s court, Madame Tallien, was famous for bathing in strawberries. Allegedly she used up to ten kilograms of strawberries per bath.

The red, heart-shaped fruit is often associated with romance, passion, innocence, and healing. Even William Shakespeare, the much acclaimed English author, decorated the handkerchief of Desdemona, one of the characters in the drama Othello, with strawberries.

The indigenous peoples of North America, and Central and South America used wild strawberries in many dishes, and the first colonists in America found that the Indians cultivated a wild strawberry that was superior in size and flavour to the European variety, but they did not even bother cultivating strawberries because they were so abundant in the wilds.

From the 16th to the mid-19th centuries, the Musk Strawberry (Fragaria moschata), commonly called “moschuserdbeere” in Germany, “hautbois” in France, and “hautboy” in England, was widely cultivated in Europe. Native to the forests of central Europe, the musk strawberry is larger than fraises des bois, the tiny, fragrant, wild alpine strawberries beloved by backyard gardeners, and smaller than the common strawberry.

The musk strawberry has mottled brownish red or rose-violet skin, and tender white flesh. Its hallmark is its peculiar floral, spicy aroma, different from, and far more complex than modern strawberries, with hints of honey, musk and wine. The aroma is so powerful that a few ripe berries can perfume an entire room.

Because the plants are hardy and can survive in many weather conditions, while still producing an abundance of their small fruits, they continued to be widely cultivated until the mid-19th century. Sadly their popularity slowly began to wane when in 1750 a newcomer, the modern cultivated strawberry called the "pineapple strawberry” (Fragaria. x ananassa) was introduced. By the early 20th century, musk varieties had mostly disappeared from commercial cultivation, replaced by firmer, higher yielding, self-pollinating modern strawberries, but gratefully, today musky strawberries are once again gaining popularity, especially in haute cuisine, and they are still cultivated commercially on a small scale, particularly in Italy.

The modern "pineapple strawberry” (Fragaria ananassa) is the result of chance crosses in Europe between two New World species, the Virginia strawberry (Fragaria virginiana) of North America, and the Chilean strawberry (Fragaria chiloensis). It inherited its hardiness, sharp flavour and redness from the Virginian, and its firmness and large fruit size from the Chilean.

The Virginia strawberry of North America reached Europe in the 1600’s but the spread of this new relatively hardy species was very gradual and it remained little appreciated until the end of the 1700’s and early 1800's when it became popular in England.

A French spy making maps of Spanish forts, brought the Chilean strawberry from Chile to France in 1714, and this species had a very important quality the others lacked, namely “size”.  It had fewer but larger flowers, giving rise to larger fruit. However, at first introduction to Europe, the Chilean strawberry was not hardy and was difficult to grow inland, away from mild coastal climates, and where it did grow, the plants grew vigorously but produced no fruit, so it was not very popular in Europe. 

It was the French who first accidentally pollinated the Chilean strawberry with the Virginia strawberry, when female Chilean plants were inter-planted with male Virginian plants, and natural hybrids were made. Antoine Nicolas Duchesne, a French botanist, began to study the breeding of strawberries and made several discoveries crucial to the science of plant breeding, such as the sexual reproduction of strawberry. Duchesne discovered that the female F. chiloensis plants could only be pollinated by male F. moschata or F. virginiana plants, and so people became aware that strawberry plants had the ability to produce male-only or female-only flowers.

However, it was the English who did most of the early breeding work to develop the many varieties of F. ananassa which form the basis of the modern varieties we enjoy today. Further breeding was also conducted in Europe and America to improve the hardiness, disease resistance, size, and taste of these strawberries.

All modern strawberry varieties have descended from this crossing of Virginia and Chilean strawberries. The transition from these native species to modern varieties was a long process, involving the hybridization of the two species, then hybridization of their descendants, and back-crossing to the original parents, plus selection of plants with desirable traits for further breeding.

Cultivation of strawberries began in earnest in North America in the early part of the 19th century, when strawberries with cream quickly became considered a luxurious dessert. With the advent of the railroad, and the ability of shipping the crop in refrigerated railroad cars, New York became a strawberry hub, and production spread to Arkansas, Louisiana, Florida, and Tennessee. Now 75 percent of the North American crop is grown in California, and many areas have strawberry festivals, with the first one dating back to 1850.

Today, China is the top strawberry producing country in the world, accounting for more than 40% of production. The United States is the second biggest producer accounting for roughly 15%, followed by Mexico, Spain, Turkey and Egypt, which each accounts for 4 to 5% of the total production.

The first strawberry varieties were brought to South Africa way back in 1656 by Jan van Riebeeck, the first Governor of what was then known as a Dutch settlement, and by 1972 The South African Strawberry Growers Association was established to provide growers with a platform where specific issues can be addressed to the mutual benefit of its members.  Due to a growing demand for strawberries, production has increased significantly in South Africa, but because strawberry production is expensive and labour intensive, only about 12 producers account for roughly 90% of all production.

Almost half of South Africa’s strawberries are sold fresh, locally. The rest is either processed or exported to other African countries, such as Swaziland, Namibia, Mozambique, and Mauritius, or to Middle Eastern countries, such as the United Arabian Emirates, Qatar and Kuwait.

Most of South Africa’s strawberries are produced in Brits in the Free State, as well as in George, Paarl and Stellenbosch in the Western Cape. About half of the strawberries grown in South Africa are produced outdoors, while the other half is grown under protection.

Strawberries remain one of the most popular garden fruits and are relatively easy to grow, and if space is limited strawberries can be grown vertically, in strawberry gutters, or in pots or special strawberry pots, as well as hanging baskets, enabling gardeners to produce large quantities of fruit from a very small area. One healthy plant can produce 500g or more of fruit per season, and a well-managed bed can remain productive for up to three years.

Many hybrid cultivars have been bred over the years, and the success of any one type may vary considerably from one area to another; so it is best to seek advice from your local nursery to select varieties that are best suited to your region. Buying from a reputable nurseryman will also ensure that your plants are virus-free.

Health Benefits:

Strawberries are fantastic when it comes to boosting the immune system, fighting disease and restoring health. And we know that red and blue berries are believed to be cancer-fighting fruits. Strawberries are rich in vitamins and minerals, and because they have very few calories, fit well into weight-control programmes.

Strawberries are considered a superfood because of their high vitamin, mineral, fibre and antioxidant content. Strawberry “seed” is also rich in Omega 3.  The fruit and leaves are used to treat a wide variety of conditions, ranging from arthritis to fever, intestinal and kidney ailments to blood purification and anaemia. They may also be used as compresses to treat rashes.

The leaves are rich in iron and vitamin C and make an excellent tea which can also be used to treat diarrhoea, kidney problems, throat infections, digestive upsets and relieve gout.

Strawberry juice may be used to soothe sunburn and skin blemishes and can whiten teeth and tone gums.

Strawberry Water. Image by Photo Mix from PixabayStrawberry Water. Image by Photo Mix from PixabayIn the Kitchen:

Besides just enjoying strawberries raw with cream, ice-cream, or yogurt, or in tarts and cakes, jams, drinks or syrups, look for unusual ways to use strawberries online – your family and friends are sure to be blown away with the many exciting flavours that go beautifully with strawberries.

Unusual combinations with strawberries include:

‘Strawberry Salsa’, where strawberries, mango, jalapeño, lime and cilantro mingle beautifully to create a sweet ‘n spicy salsa that tastes so good, you’ll have to hide it away, or make double for those who just love to eat it with a spoon.

‘Strawberry Balsamic Chicken’ is a refreshing summer dish of balsamic-marinated chicken breasts, topped with a ‘Strawberry Caprese Salsa’ made from fresh strawberries, basil and mozzarella cheese, with a final drizzle of reduced balsamic vinegar for an extra kick – divine!

Even a simple ‘Strawberry Balsamic Vinaigrette’ will have everyone coming back for seconds, and if it is used to dress spinach, perhaps even small children will eat their greens!

Encourage your family to drink more water by making ‘Strawberry, Lime, Cucumber and Mint Water’ - the simple addition of fruit and mint makes ordinary water extraordinary!

Strawberries can easily be frozen for consumption any time of year. Wash the berries, hull them, lay them on a parchment-lined baking sheet so they are not touching and freeze them until solid. Then transfer the individually quick-frozen berries to a freezer-safe zip-top bag and keep frozen for up to one year. Pop-out as many or as few as you like to use year-round. Frozen berries are especially good for smoothies.

In the Garden:

Strawberries with their attractive foliage and pretty flowers can easily be incorporated into the garden. Try planting a strawberry pot and place it in a sunny part of the garden, or plant up a few hanging baskets for a sunny patio or balcony garden. And if space is limited, but you want to grow several plants, a vertical strawberry garden can look so pretty and even makes a wonderful screen for privacy.

Marigold 'Taishan' Picture courtesy Ball StraathofMarigold 'Taishan' Picture courtesy Ball StraathofCompanion Planting:

Companion plants are plants that interact well when planted in close proximity to one another. Biologists aren’t entirely sure how companion planting works, but the technique has been used for centuries to enhance growing conditions, attract beneficial pollinators, control pests and take advantage of available space.

Herbs are used for their strong scent which disguises the scent of the crops the insects are attracted too. They are also most important to attract beneficial pollinators to the plants, and this is especially good for strawberries. Because strawberries are prone to attack by a number of pests, it makes perfect sense to plant them alongside neighbours which help keep invaders at bay.

In very hot regions strawberry companion plants can provide light shade for the strawberries when the midday sun may be a little too strong. Inter-planting in this way also creates a living mulch to keep the soil cool and helps to keep weeds in check.

Remember to use taller companions like borage in beds in close proximity to your strawberries, but not directly inter-planted between them, or they will dwarf the strawberry plants. Smaller crops like lettuce are perfect for inter-planting. Herbs can be planted into pots which are placed between your strawberry crop, and these can easily be moved to another spot in the vegetable and fruit garden as required.

There are many companion plants for strawberries, including:

Herbs like Borage with its beautiful blooms will attract pollinators and beneficial insects, while strengthening the strawberries resistance to disease. Many gardeners claim that borage also makes strawberries taste even sweeter.

Thyme is excellent to plant around the border of a strawberry patch to deter worms. Thyme also attracts syrphid flies (also known as hover flies). These beneficial insects dine on soft-bodied pests such as aphids, thrips, scale, and caterpillars.

Caraway is planted to attract parasitic flies and wasps as these tiny, beneficial insects are voracious eaters of grubs, cutworms, beetles, scale, caterpillars and other pests.

Dill, fennel, coriander, and sage are also excellent companions for strawberries, helping to repel slugs and other pests.

Many gardeners believe that inter planting lettuce and spinach with strawberries enhances the productivity of all three plants.

Beans and other legumes are natural fertiliser producers because they fix nitrogen into the soil by means of bacteria in their roots. Bush beans would be perfect planted in alternate rows with strawberries.

Because of their pungent smell, chives, onions garlic, and other members of the allium family are excellent strawberry companions which discourage marauders from feasting on their juicy berries.

Marigolds and strawberries make a beautiful team, and the distinctive aroma of the sunny blooms of marigolds will discourage many pests. Because marigolds attract red spider, they are also often grown in alternate rows between strawberries as a “bait crop”. Once bait crops are infected they are pulled up and disposed of, in other words they are sacrificed for the crop they are planted to protect. Root knot nematodes can do considerable damage to the roots of strawberry plants and French marigolds are known to help repel root knot nematodes. Once the marigolds are finished flowering, they are dug back into the ground as a green manure. Because marigolds seed themselves freely, you can continually have a supply to use.

Nasturtiums are another great bait crop because aphids are attracted to them and the infected plants are easy to pull up and dispose of. They also seed themselves freely, making them a very economical bait crop. The dwarf varieties are beautiful to use in the herb, fruit and vegetable garden.

Flowers with plenty of pollen like the annual alyssum attract beneficial bugs and bees to pollinate the flowers, ensuring a bumper crop.

Don’t plant strawberries where you have previously grown potatoes, tomatoes, eggplant and peppers as there may be potential pathogens lurking in the soil.

Strawberry Bed. Image by Maria Godfrida from PixabayStrawberry Bed. Image by Maria Godfrida from PixabayCultivation, Propagation and Harvesting:

Strawberries are more tolerant of variations in climatic weather compared to many other crops. However, climatic factors such as temperature, volume of water available, and wind can influence the growth and production of strawberry plants. Strawberries are very hardy to frost, but in extremely cold regions the plants will go dormant in winter. Strawberries will also tolerate subtropical conditions, where fruit production is usually during the cooler months.

Although strawberries are grown in full sun, at least five to six hours of full sun a day is a must, and flower initiation is dependent on low temperatures and short days. Fruit size and quality is also enhanced by cooler temperatures, and high summer temperatures have a negative effect on fruit size as well as fruit quality.

In South Africa, strawberries should be planted as early as possible during the periods given below, as the degree of growth prior to winter will determine their production potential. Gauteng and the summer rainfall regions (February to March); Free State (February to March); KwaZulu-Natal (March to June); Western Cape (March to May).

Always purchase good, virus-free runners from a reliable nursery, and don’t plant strawberries where you have previously grown potatoes, tomatoes, eggplant and peppers as there may be potential pathogens lurking in the soil.

Strawberry plants are usually established in beds and planted on raised ridges, and for the home gardener it's a good idea to grow strawberries in containers as this makes the fruit less accessible to snails and centipedes. Classic terracotta strawberry pots are practical and look very pretty, and an old keg or wine barrel makes a lovely, rustic feature. Even wooden vegetable crates lined with plastic will suffice. In fact, almost any kind of container will do, from simple pots, window boxes and hanging baskets to the latest vertical wall and stacking systems. Birds love strawberries as much as humans do, so be prepared to also invest in a roll of bird wire.

If possible fill your containers with soil, or prepare the beds for planting strawberries a few weeks before planting time. Good soil preparation is vital because your strawberries will live their three-year lifespan in the same beds or pots.

Strawberries will not tolerate poor drainage and they thrive in neutral to slightly acid soil, growing best in a soil with a pH of 5.0 to 5.5, and doing well with the addition of plenty of well-rotted organic material like compost and well-rotted manure.  Strawberries can be grown in more clayey soils if a sufficient quantity of compost is added to the soil during soil preparation. Saline and waterlogged soils should be avoided. If you want to increase the acidity of your soil, dig in acid compost, and if your soil is too acid, a dressing of agricultural lime or wood ash forked into the soil a couple of weeks before planting will correct acidity levels. The potassium in the wood ash also stimulates flower and fruit formation.

The relatively shallow roots of a strawberry plant are mainly concentrated within the top 20 to 30cm of soil, so if you are planting into beds, the soil should be dug over thoroughly to a depth of about 30cm, with added fertilisers like 2:3:2 and a generous dressing of bone-meal.

Potted plants will do well in a good potting soil mixed with a little compost, and fertilisers like 2:3:2 and a generous dressing of bone-meal. Incorporating water retaining granules to reduce the required watering frequency is highly recommended. Test the drainage of the soil before planting by watering it thoroughly, the water should drain away easily, and when the soil is dry it should not be hard and caked. Wait a few days for the soil to settle before planting, and once it has settled it may be necessary to add more soil to the pots at planting time.

Plant spacing will depend on the variety grown, but is usually about 20 to 30cm apart, in rows 30 to 40cm apart. Avoid overcrowding the plants as this encourages diseases. When planting, Firm the roots down into the soil but be careful not to cover the crowns of the plants with soil.

After planting mulching the soil will help to retain moisture, and keep the fruit cleaner. Organic material such as straw, lawn cuttings, wood chips, or bark can be applied between the beds. If you are planting in plastic sheeting, first prepare the beds, lay the plastic and then cut holes into the sheeting and plant. Another way is to cover the prepared planting area with weed matting, cutting slits with a sharp knife, through which you can plant.

Strawberries need a constant supply of nitrogen, especially after they have just been planted, and any source of nitrogen can be used. However, care should be taken when using granular fertilisers such as limestone ammonium nitrate (LAN) as to much can burn the plants, and all the granules should be removed from the leaves by applying irrigation directly after fertilisation.

Well-fed strawberries taste better, and potassium is vital for the formation of flowers and to ensure good quality fruit, so during the growing season, but especially once the flowers appear, feed your plants monthly with an organic 3:1:5. If you are growing in sheeting or in pots a liquid fertiliser is much easier to apply without burning your plants. Brands sold for feeding tomatoes work very well for strawberries.

Water young plants regularly until they are established, and once they are established, depending on your climate and rainfall, they will require deep watering about 2 to 3 times per week until the fruit starts to ripen. Regular irrigation is especially important in the winter rainfall regions. Never allow the plants to totally dry out and wilt, but on the other hand avoid waterlogging which can cause root disease. Reduce watering as the berries mature, or their flavour and firmness will be affected.

To help prevent fungal diseases, try not to wet the leaves when watering, and if you are watering overhead, try to water in the mornings so the foliage can dry completely before sundown. For this reason drip irrigation is perfect for strawberries.

Later in the season the plants send out runners which will take root to form new plants. Regularly removing all runners during the growing season will encourage better fruiting, but if you want to propagate new plants, simply cut the runners off from the parent plant and transplant them elsewhere, or just continue to let them grow where they rooted to produce new plants. 

Allow the fruit to ripen on the plants for the best flavour, and pick when fully ripe, by pinching or snipping through the stem.

Once fruiting is over the leaves can be cut back to leave just the central, young leaves intact. This will ensure that the plants bulk up again before winter. Be sure to also remove any old or mouldy fruit lying on the ground. Top-dress established plants with compost and manure in spring and autumn.

Well-cared-for plants can remain productive for up to three years, after which the quantity and quality of the berries can become unsatisfactory, and they get affected by viruses. Dig them up and discard the plants, replanting in another area of the garden with fresh stock from your nursery. 

Crop rotation is essential for strawberries and they should be rotated with garlic, onions, carrots, beetroot, radish, spinach, lettuce, cabbages, beans and peas. A period of 2 years should have passed before the crop is established again on the same plot.

Problems, Pests & Diseases:

Properly cultivating strawberries goes a long way to producing healthy crops. The main points to note are the following: Avoid planting strawberries in poorly drained soils; avoid planting in areas where pests and diseases prevailed; apply crop rotation practices; remove weeds and any unwanted crop residue; choose pest resistant cultivars; aerate the soil before planting.

Companion planting and DIY environmentally friendly insecticides can be sprayed regularly on healthy crops to help keep them healthy. Infusions (tea) can be obtained from herbs such as sweet basil, garlic or khaki bush weed.

Strawberries are very sensitive to all nematode (eelworm) species. They attack the roots of the plants and can severely inhibit the growth of the plants. The occurrence of small, deformed growths (galls) on the roots of the plants is usually an indication of nematode infestation. There are no chemicals available for gardeners to use, but fortunately nematodes can be controlled without chemicals by starting with nematode-free plant material and following crop rotation practices. Nematodes can partially be controlled by planting marigolds, and the addition of organic matter such as matured compost and manure. The organic matter stimulates microorganism activity within the soil in order to establish a natural balance.

Red spider mite infestations present one of the biggest problems in strawberry production. They can cause severe damage to a plant by sucking the sap from the leaves. It is very difficult to control red spider mites as they appear to have a developed a certain degree of resistance to most of the miticides which are currently used. Red spider mites are usually visible as tiny red spots on the underside of the leaves and are particularly active on leaves which are exposed to direct sunlight. Heavy infestations can be identified by visible shiny threads, which are produced by the mites. Although there are insecticides available which can be used to eradicate this pest, adequate control can usually be obtained by spraying the affected plants with a diluted sugar or soap solution, or infusions (tea) as listed above. Ensure that the spray reaches the undersides of the leaves in order to control red spider mite. Remember that any chemical formulation that is used to kill red spider mites would also kill their natural enemies, which can often exacerbate the problem. Red spiders love marigolds, and they can be planted in another bed close to use as a “bait plant’.

Other pests, which generally damage the plants or fruit, include: crickets, snails and slugs, aphids, American bollworms and cutworms, millipedes and certain kinds of beetles. The best method of controlling these pests is by using a suitable organic spray as a preventative measure.

Leafspot, also called chocolate spot, is the most frequent fungal disease which affects strawberry leaves. The first signs of this disease appear as small, brown spots on the upper leaf surfaces of older leaves. The number of spots is usually an indication of the extent of the disease. The key to good control is proper sanitation. Infected and old leaves should be removed. Good air flow through proper plant spacing will minimise the spread of the disease. Hot, humid conditions promote fungal infections.   

Reddish-purple spots and blotches on the leaves can identify powdery mildew, another fungal disease which inhibits plant growth, reduces the yield and reduces fruit quality. Closer examination would reveal white, powdery mycelium which is a loose network of the delicate filaments (hyphae) that form the body of a fungus. Warm, wet weather conditions are favourable to the occurrence of fungal diseases and the longer these conditions prevail, the higher the risks of fungal infections will be. Plants should therefore not be spaced too densely as it will take a long period for the leaves to dry. Copper-containing chemicals, such as copper oxychloride, will control fungal diseases to a reasonable extent, especially if applied as a preventive measure.

Botrytis is a grey mould which is most probably the biggest enemy of strawberries. This disease can only infect damaged or dead plant tissue. Most of the infection occurs during the flowering period, especially during hot, humid weather conditions. Fruit which is damaged by insects or other means is usually infected. The infected fruit consequently starts rooting and will eventually be covered with a dense grey blanket of mycelium. The fungus can also affect dying petals and stamens and will spread rapidly to the developing fruit. Botrytis can be controlled by fungicides which are formulated specifically to control it.

Botrytis can also be controlled by following sensible cultivation practices. Cultivation practices which would enhance the infection by the fungus should be avoided. Plants should not be spaced too closely. More water should be applied per irrigation and the intervals between irrigations should be increased. This would allow the leaves to dry and therefore inhibit fungal infection. Excessive application of nitrogen fertiliser should be avoided as it would stimulate excessive leaf growth. This, in turn, will lead to a dense canopy of leaves which would create humid conditions with consequential fungal infection. The disease will spread rapidly on fruit which is in direct contact with warm, wet soil or on wet organic material. The use of plastic mulching can assist in avoiding this problem. Infected fruit should be removed and disposed of by either incinerating it or burying it in an area far from the strawberry field.

Other fungal diseases which attack strawberry plants include: leaf scorch, leaf blight, leather rot, Anthracnose and red stele root rot.

Caution:

Strawberries are not poisonous for dogs and are actually good for them. They are also non-toxic to felines and thus, they're safe in moderation. However, the stems and foliage are very difficult to digest. Consequently, a cat eating the stem can cause gastrointestinal obstruction.

Always supervise babies and small children in the garden, and always discourage your pets from chewing in plants.