Month: July 2020

Planting strawberries: when & where

Planting strawberries: when & where

The sweet strawberries simply taste best from your own garden. We’ll tell you how best to plant strawberries. Growing strawberries (Fragaria) in your own garden or on the balcony is actually not difficult. With the right soil in the right location, correct maintenance, fertilisation and watering,…

Types of cucumbers: new & heirloom cucumber varieties

Types of cucumbers: new & heirloom cucumber varieties

New, old and resistant cucumber varieties in an overview. Seeds of the varieties are available online or in your local garden centre. Some might be surprised to learn that there is actually a great diversity among cucumber varieties. The elongated vegetables differ in colour, shape,…

Powdery mildew on grapes

Powdery mildew on grapes

Get rid of powdery mildew on wine and grapes! Find out here which household remedies or natural sprays work well against the fungal disease.

Grapes are becoming increasingly common to grow in gardens at home. Regardless if the grapes are later processed into juice or wine, a powdery mildew infestation can endanger the entire harvest. It is of secondary importance whether you are dealing with powdery mildew or downy mildew. Both pathogens can cause considerable damage. With a few tips, however, you can get the mildew plague under control and prevent it from becoming superfluous.

Powdery mildew vs. downy mildew

One of the main characteristics of powdery mildew is the grey to white fungal coating on both young shoots and leaves. Infested grapes stop growing and dry out, whereas larger berries burst open and can be infested by other pathogens. Compared to that, downy mildew causes round yellow spots with an oily sheen to appear on the underside of the leaves. Downy mildew appears exclusively on the underside of leaves. The grapes are not spared the wrath of downy mildew either, they dry out and become leathery after a mildew infestation. Since grapes are perennial, both types of mildew can unfortunately survive the winter on the plants unscathed. If a mildew outbreak is untreated, it is highly probable that a new breakout will occur next season.

Preventing mildew on grapes

By abiding by the following rules the mildew will be less likely to gain a foothold on your plants in the first place. Grape vines should be given enough space so that air circulation is provided. Densely growing shoots and foliage considerably increase the probability of an outbreak. However, choice of the grape variety can determine the success of the harvest. Powdery and downy mildew are imported diseases, which is why native European grape varieties lack resistance to the fungus. The following varieties are very susceptible to powdery mildew: ‘Portugieser’, ‘Elbling’, ‘Kerner’, ‘Trollinger’, ‘Silvaner’, ‘Muskateller’. Grape varieties such as ‘Müller-Thurgau’, ‘Gutedel’, ‘Portugieser’, ‘Limberger’ are more likely to be infested with downy mildew. By the way, grape berries are no longer edible even with a slight mildew infestation because they develop a very unpleasant taste.

Using baking powder and milk against mildew

Mildew, regardless of whether it is powdery or downy, sticks extremely stubbornly to grape vines. In early spring the fungus begins to grow again and is likely to infest the fresh new shoots of grape plants. There are many cures that the internet tries to offer to the desperate gardeners. However, household remedies such as baking powder or milk are rarely of any help against mildew. It is possible, though, to treat mildew with natural sprays. Copper based preparations are the best way to go. The spray should be applied to the affected plants several times, otherwise the mildew can survive. To increase the likelihood of the treatment’s success we advise to read the instructions manual of the product carefully. Resistant grape varieties are often less susceptible to mildew and are more easily treated when infected.

Is the box tree moth poisonous?

Is the box tree moth poisonous?

The box tree moth caterpillars feed on the toxic buxus. Find out here whether the box caterpillars are poisonous and if they can be touched safely. Many regions of Europe are affected by the box tree moth (Cydalima perspectalis). During the treatment, one has to really…

Types of beans: robust, heirloom & new varieties

Types of beans: robust, heirloom & new varieties

Beans are enormously diverse. From old heirloom bean varieties to newly cultivated ones: there is a lot to discover! If you want to grow beans in your own garden and are therefore looking for the right variety, you should first decide which type of beans…

Christmas cactus care: location, watering & fertilising

Christmas cactus care: location, watering & fertilising

In order for the Christmas cactus to bloom in full, the right care including proper location, fertilising and watering must be provided.

Christmas cactus: choosing the right location

The varieties of Christmas cactus (Schlumbergera x buckleyi), which are usually available for purchase during winter in specialist shops, are hybrids which have been created by crossing different wild species of the genus Schlumbergera. These cacti species are native to tropical and subtropical areas of Brazil. Accordingly, Christmas cactus does not like temperatures below 10 °C.

Due to the Christmas cactus’ tropical origin, it is best to keep it as a houseplant in regions with temperate climates. If the weather permits it in summer, it can of course be relocated outside to enjoy some warmth. However, it is best to place the cactus in a semi-shady location because the full sun does not agree with this plant. Once the temperatures start to fall again in autumn, the plant should be placed back inside in order to avoid damages inflicted by the cold.

These are the general rules that apply to the choice of the location for the Christmas cactus:

  • Temperatures below 10 °C should be avoided
  • Christmas cactus should be kept as a houseplant (most of the time) in temperate climate zones  
  • If the temperatures allow it, the cactus can spend the summer outside
  • Choose a place that is somewhat in the shade – the Christmas cactus does not tolerate direct sunlight

The Christmas cactus starts to form flowers in October. In order for the flowers to form fully, there are several measures that need to be taken. First, the Christmas cactus should be kept slightly cooler (around 15 °C) from October onwards. Second, at this stage it should not be exposed to daylight longer than 9 hours a day. We recommend placing the cactus in a special location where these conditions are ensured. As soon as the first flower buds are observable, the daylight supply as well as the temperature can be increased (up to 20 °C). These conditions can be maintained until the Christmas cactus moves to its summer quarters.

In order to let your Christmas cactus bloom in full glory, these measures should be taken:

  • To form flowers, lower the temperature (15 °C) and reduce the amount of light (short day: maximum 9 hours of daylight)
  • As soon as the flower buds form, move the plant to a bright location and let the temperature rise to 20 °C
  • Provide the Christmas cactus with a relatively bright and warm location until it can be relocated outside for the summer months.

Even if you intend to keep the Christmas cactus in a pot, the substrate plays a decisive role in the wellbeing of the cactus. One of the possible options is to use commercial potting soil, regardless if it contains peat or not. The most optimal pH value of the substrate for Christmas cactus is between 5.5 and 6.0. In addition, the substrate should be as permeable as possible, as the Christmas cactus reacts very sensitively to even the slightest amounts of stagnant moisture. The permeability can be easily achieved by adding sand to the substrate: use a 1 to 4 sand to substrate ratio.

Soil requirements of the Christmas cactus summarized:

  • Substrate: commercial potting soil, regardless if peat-free or not
  • pH value from 5.5 to 6.0 is optimal
  • Choose a substrate with a loose structure so that it is more permeable to water
  • Add sand to the substrate to increase the permeability of the substrate and thus counteract waterlogging (use a 1 to 4 sand to substrate ratio)

Watering Christmas cactus properly

In short, the demand for water strongly depends on the development phase of the Christmas cactus. During bloom, the cactus should be watered approximately once a week, depending on the room temperature. In the resting phase that follows the bloom, frequent watering is unnecessary. Just make sure that the cactus does not dry out completely. The growth of new shoots indicates the beginning of a new growth phase. At this stage, the cactus’ need for water increases, which is why it should be watered more often.

If the Christmas cactus is kept outside for the summer, it should be watered ideally every two to three days. However, it is advised to place the cactus in a sheltered place where it won’t get rained on as that could lead to waterlogging. The substrate should be kept moderately but evenly moist. Neither extreme – too dry or too wet – have a positive effect on the growth of the Christmas cactus. During the resting phase before flowering, the watering can be halted completely.

This is the summary of what to keep in mind when watering the Christmas cactus:

  • Water regularly during flowering (approx. once a week)
  • Keep the substrate evenly moist and do not let it dry out
  • In summer, keep the cactus outside but sheltered from the rain
  • During the main growth stage, water the cactus every 2 or 3 days
  • During the resting phase before bloom (from October), reduce or completely avoid watering

Fertilising Christmas cactus properly

The Christmas cactus should only be fertilised during the main growing phase (April to September). There is no need to fertilise when the cactus is in bloom or any other time. An easy way to do that is to purchase a multiple-nutrient fertiliser from your local gardening centre. Usually, there are two options available: either organic or mineral fertiliser.

If you decide on the organic fertiliser, pick the liquid version. In this form, the nutrients are available to the plant more quickly than if, for example, horn shavings or compost were used. In any case, follow the instructions on dosage as stated on the instruction manual or on the packaging of the respective fertiliser – regardless whether organic or mineral fertiliser is used. Using these instructions, fertilise the Christmas cactus every four weeks during the main growth phase (April to September).

In general, this is how the Christmas cactus should be fertilised:

  • No fertilisation required during bloom, resting period before flowering (from October) and the time between flowering and the formation of new shoots
  • Fertilise the Christmas cactus between April and August/September (the main growth phase)
  • Use multiple-nutrient fertilisers – mineral or organic
  • Read the instruction manual of the purchased fertiliser
  • Fertilise every 4 weeks during the growth phase
Types of courgette: best heirloom & new courgette varieties

Types of courgette: best heirloom & new courgette varieties

Courgettes are easy to grow in the garden. Here you can find out about the heirloom and new varieties of courgettes. The courgettes (also: zucchini or summer squash) sold in supermarkets usually belong to the common long and green variety. Because of that, many do…

Box tree moth treatment: natural methods

Box tree moth treatment: natural methods

Treating the box tree moth without poison: here is our guide to natural methods of control against this annoying pest. Even though your boxwoods (Buxus) might be under attack by the ravenous box tree moths (Cydalima perspectalis), it does not mean all is lost. It is…

How to recognise the box tree moth?

How to recognise the box tree moth?

It is essential to identify the presence of the box tree moth before it is too late. This article has all the necessary information on timely detection of this pest.

You have probably already heard that the box tree moth (Cydalima perspectalis) is a dangerous pest on box trees (Buxus). But detecting this species and distinguishing its symptoms from other diseases of the box tree can be challenging. Read below to find all the information for the protection of your beloved evergreen shrubs.

How to detect the box tree moth

In order to recognise an infestation of the box tree moth early, it is indispensable to know how to correctly control the box tree moths. In this article, you will learn when to check and how to recognise the infestation. Below you will find a few tips on fighting the disease.

Box tree moth: when to check?

You won’t find eggs, caterpillars and adults of the box tree moth all year round. The caterpillars survive the winters and are followed in spring by pupae and adult moths that lay eggs and a new generation with successive stages of development. Unfortunately, these stages occur at slightly different times each year, depending on temperature and weather conditions.

The following table summarises the occurrence of eggs, caterpillars, pupae and cocoons. However, the table depicts the normal progress in the development: any deviations from the norm in terms of weather will impact the rate at which the insects develop. Particularly warm years lead to a faster development of the insect and more generations occurring in one season.

MonthAprilMayJuneJulyAugustSeptember
Stage of developmentCaterpillars (overwinter)CocoonsMoths, eggsEggs, caterpillarsCocoons, mothsMoths, eggs, caterpillars
RecommendationUse trapsUse trapsUse traps
GenerationPrevious year’s generationPrevious year’s generationGeneration 1Generation 1Generation 2Generation 2

It is important to note, that the stages of development can vary depending on climate conditions. Therefore, it is important to do regular check-ups on your box trees and use pheromone traps to uncover the box tree moth presence in time.

Monitoring box trees

From April, the inner part of box trees should be checked for the overwintered box tree moth caterpillars. To be truly safe, the shrubs need to be inspected diligently from the inside and the outside at least once a month until September. Around June, the overwintered generation of caterpillars transforms into adult box tree moths and therefore can also reach your box trees from neighbouring gardens. This is the right time to use pheromone traps to notice the moths ahead of time. Finding out about the flight of the adult moths will indicate when eggs and young caterpillars will be found on their box trees. This happens about two weeks after the moths first fly.

Detecting a box tree moth infestation

The box tree moth lives pretty secretly in almost all phases of life. Groups of up to 20 eggs are deposited in the outer areas of the shrub on the undersides of the leaves. They are to be discovered only in the time directly after the moths first fly and you need to be very attentive in order to glimpse them. As soon as the small, green-yellow larvae hatch, they set off into the interior of the box tree, where they hide in the caterpillar webs and leaves. In this phase, white webs can be observed inside the shrub. If these are opened, they contain young larvae and excrement crumbs.

Older larvae move to the outside of the box tree. In this phase, the infestation is easily recognisable: the caterpillars now eat whole leaves and the bark is also destroyed – as a result, entire parts of the box tree die and turn yellow. A sure sign of a box tree moth infestation are the green-yellow caterpillars with black and white stripes and the characteristic black head capsule, which are up to 5 cm long. At this stage, even the white webs should be more visible.

During the metamorphosis, the caterpillars pupate to similarly coloured, 2 cm long pupae, that are also spun into leaves. The flight of the butterflies is not very obvious without the use of pheromone traps because the moths are active at night. If there is a fragrant butterfly bush (Buddleja davidii or Buddleja alternifolia) in the surrounding area, sometimes the box tree moth can also be found there during the day. If you have discovered adult moths in your garden, you should keep an intensive lookout for eggs and larvae in the coming days to prevent a severe infestation from occurring.

cydalima perspectalis caterpillar
Box tree caterpillars target the foliage of box trees [Shutterstock.com/ PhotoStorm_22]

Summary of how to detect a box tree moth infestation:

  • Eggs can be found shortly after the moths first fly in the outer areas on the undersides of the leaves.
  • Young, yellow larvae can be found inside the box tree, hidden in white webs.
  • Older, darker coloured caterpillars can be found outside of the shrubs. The shoots of the buxus become yellow and die, the foliage is destroyed and the caterpillar webs can be seen clearly.
  • Pupae are in the webbing made of caterpillar silk and leaves.
  • The adult box tree moths can be spotted by pheromone traps or observed on butterfly bushes (Buddleja).

Box tree moth: what to do in case of an infestation?

If you discover a box tree moth infestation, it is essential to act promptly and get to the treatment right away:

  • Prune your box hedge about two weeks after you have observed the adult box tree moths. This will remove the eggs and the freshly hatched larvae.
  • Cut the webs with the young caterpillars out from the inside of the box tree.
  • Once the caterpillars have grown and move to the outside of the bush, use natural sprays. In the preceding stages, the caterpillars are protected by their webs very well. If the infestation is low, you can collect the caterpillars manually or flush them away with a strong jet of water using a gardening hose. Here you can read what you should consider when handling the poisonous box tree moth.
  • Young larvae and eggs can be disposed of alive; discard the older caterpillars and pupae after they have been killed. Read more about how the box tree moth can be disposed of here.

You can find detailed information on how to get rid of the box tree moth here.

Box tree moth: life cycle, identification & treatment

Box tree moth: life cycle, identification & treatment

Learn everything you need to know in order to recognise and treat an infestation by the voracious box tree moth and its caterpillars here. Have you noticed any discoloured leaves, dead branches, white webs and caterpillars on your box tree (Buxus) – or observed these…