Cucumbers are heat-loving plants and since the weather is often unreliable in early summer, they are often grown in greenhouses. In order to achieve a good harvest, it is particularly important to properly care for the plants. A common problem that many gardeners face when growing is yellow cucumbers. Find out why cucumbers turn yellow in the greenhouse and what you can do about it.
It's not uncommon to lose a few fruits each harvest, but if your cucumbers are constantly turning yellow, there are a few possible causes. To minimize crop losses, we will help you examine the most common reasons for this.
Yellow cucumber varieties
Before you panic, check the variety of cucumber you grew. There are several varieties that are actually yellow and you shouldn't worry that there is something wrong with the plants.
- Lemon cucumbers:They have small, round fruits with a yellow skin and light green flesh.
- Cucumber:It is also small and round, but has creamy white flesh and the yellow peel can be eaten.
- Dutch yellows:This yellow variety contains less water and has an intense taste.
The cucumbers are overripe
The most common cause of yellow cucumbers in the greenhouse is late harvest. Many inexperienced gardeners make the mistake of letting cucumbers grow for too long. This causes them to become yellow, soft and bitter. Most cucumbers take between 50 and 60 days from sowing to reach maturity and taste best when slightly unripe and crunchy.
It is best to cut off the overripe fruits so as not to prevent further fruit and flower formation. Add the yellow cucumbers to the compost if they are not affected by a disease or pest, as they certainly do not taste good.
Overwatering results in yellow fruits
Thick, yellow cucumbers that taste bitter are the result of overwatering.
To prevent this,water the cucumbersin the greenhouse always at the base and keep the leaves dry. Water them thoroughly a few times a week, early in the morning.
On the other hand, inadequate watering can cause small fruits to form.
Nutrient deficiency causes yellow discoloration
Cucumber plants are heavy feeders and therefore you should add compost to the soil in spring and autumn. The plants should also be heavily fertilized during the growing season.
Infertile soil can result in stunted or yellow fruit. This is especially true if you plant your cucumbers in the same spot in the greenhouse every year and don't change the soil.
If yellow cucumbers are a constant problem, it's probably due to a nitrogen deficiency. It is best to fertilize your plantswith a natural fertilizer, to enrich the soil and avoid yellow cucumbers in the future.
The cucumbers in the greenhouse are not pollinated
If you notice that some flowers fall off without bearing fruit, or if you get lots of small, yellow cucumbers, this is a sign that your plants are not properly pollinated.
Self-pollinating varieties are usually planted in the greenhouse, but these also need a few bee visits. Make sure the greenhouse is properly ventilated and insects have access to it.
You can attract bees by spraying the plants with a solution of water and sugar (or honey). Or do pollination by hand, using a cotton swab or brush to transfer pollen from male flowers to female flowers.
Diseases that cause yellowing
There are also some diseases that can affect the cucumber fruits and cause them to yellow.
Powdery mildew is a fungal disease that limits photosynthesis, impairs growth and ultimately turns the cucumber yellow. The best prevention is to keep the foliage of cucumbers dry when watering and to ensure good air circulation in the greenhouse.
Another disease that can cause yellow fruit on cucumbers is cucumber mosaic virus. It causes misshapen, small fruits that are either white or yellow with green spots.
To avoid these and other diseases in cucumbers, avoid warm, humid conditions in the greenhouse.
High temperatures in the greenhouse
Even with good ventilation, it can get too hot in the greenhouse in midsummer and reach temperatures of over 45 °C. Temperature fluctuations and excessive humidity in the greenhouse can lead to yellowing of the fruit. To avoid this, it may be necessary to water the plants more frequently during hot periods, shade the greenhouse, and provide proper ventilation.
