Many hobby gardeners grow cucumbers in their garden. Cucumber plants are very sensitive to some situations and circumstances. It is not uncommon for cucumbers to dry up or wither away. Brown or black-brown discolorations are also common. Plantopedia explains the reason for this and what hobby gardeners can do about it.
causes
exhaustion
wasting away from exhaustion
When whole cucumber plants wither, it's usually due to a stunted growth that could be attributed to exhaustion. This occurs mainly in young plants after the first one or two cucumbers have been harvested. The young plant then usually does not yet have sufficient supply channels and nutrient stores that are required for the growth of further fruits. If new fruits have already formed, the withering of the cucumber and cucumber plant is quickly noticeable. First the fruit mostly dries up before the plant dies in the worst case.
Cucumbers can be attacked by pests
What to do?
With young cucumber plants, care should always be taken to delay harvesting for as long as possible in the first two years. In the meantime, the plant gains strength and rewards you with a bountiful harvest afterwards. More than one cucumber should not ripen on two adjacent leaf axils. Only when the cucumber height is reached should a second fruiting persist.
blossom end rot
Blossom end rot is not a fungal disease, as is often claimed, but a calcium deficiency that causes it. First, mostly smaller, watery spots form at the base of the flower. The rot spreads from the blossom to the cucumbers and can be visually recognized by brown-black spots that get bigger and bigger, then dry up and harden. First of all, young fruit formations are affected in the initial stage. They then dry out completely.
Blossom end rot on a tomato
What to do?
Since calcium plays a major role in fruit formation and ripening, care must be taken to ensure that it is adequately supplied. Cucumber plants absorb the nutrient from the soil. If the pH is around 6, calcium is present in the required amount. If the value is lower, a fertilizer containing calcium should be administered. If the pH value is normal and the cucumber plant still shows the abnormalities mentioned, this may be due to a too high salt concentration in the soil, which is caused by too much compost and fertilizers with nitrogen, magnesium or potassium, for example. This disrupts the absorption of calcium from the soil. In this case, it is advisable to replace the old soil with fresh ones and to reduce the amount of fertilizer in the future. At the same time, all damaged plant parts and cucumbers must be removed. The plant then usually recovers. In addition, it is important to ensure even watering. Cucumbers should not be too dry, but not too moist either.
anthracnose
Similar to a calcium deficiency, the damage to an anthracnose can be seen. This also causes watery spots and dark gray to brown spots on the cucumbers. These spread and, in the advanced stage, allow the cucumber to dry out. The same happens with the cucumber plant. The difference lies only in the fungus formation, which can be recognized as bright red spots on the fruit, and the fungal fluff that forms on dead tissue of the cucumber plant. New fruit sets wither/shrivel and dry up.
green cucumbers on a cucumber plant
What to do?
All affected parts of the plant must be removed and disposed of in the household waste (not on the compost due to possible spread)
Since the fungal infection can be spread by infested neighboring plants and rain splashes, overhead irrigation, insects and infected garden tools, appropriate preventive measures should be taken. Garden tools must be disinfected before use. If possible, place the affected plant in a cooler area below 21 degrees Celsius - this will inhibit further development. A fungicide from specialist retailers helps to get the fungus under control quickly.
Angular leaf spot disease
Angular leaf spot is a bacterial infection. This initially causes watery and conspicuously angular leaf spots to form. As the disease progresses, they turn brown and dry up. The fruits wither/shrivell. First greenish, later brown spots appear on the cucumber, which progressively enlarge. Coatings of mucus can form on the leaves and fruits.
What to do?
If angular leaf spot occurs, you can only dispose of the entire plant. In order to prevent the pathogens from moving into the compost, affected cucumber plants should always be disposed of in the household waste. Cucumber plants should not be grown on the same cultivation site for at least three years. Thoroughly clean garden tools and everything that has come into contact with infested plants.
lack of water
Lack of water and drop in temperature
If the temperatures drop rapidly and/or if you don't water them in time when it's dry, the cucumber shows its most sensitive side. Malformations of cucumbers are not uncommon, which usually appear in a stunted form. Young fruits in particular dry up quickly and fall off.
Cucumber plants in the greenhouse
What to do?
Once the fruits of the cucumber plant are stunted and dried up, there is no going back. Here it is important to avoid this in the future and to ensure constant temperatures without strong fluctuations as well as an evenly moist soil.
Fusarium wilt
Cucumis sativus is very susceptible to Fusarium wilt. The flower usually wilts first, then the leaves slowly turn brown and later dry up. The cucumber plant shows clear growth disturbances. The base of the stem becomes rotten. A pink colored mycelium may form. The wilt spreads to the fruit, where it causes discolouration up to brown-black. These also dry up in the course of the disease.
What to do?
There is nothing you can do other than completely dispose of affected plants in the household waste. So far, no promising control is known.
cucumber aphids
Among the pests, the most penetrating is the cucumber aphid, which can completely kill cucumber plants if treated too late.
The flesh-colored lice prefer the buds and tips of the shoots that fall off after an infestation or buds that no longer form flowers. Leaves show black dots and wither. The supply of the cucumbers suffers, so that they turn from yellow to brown.
Aphid infestation on a plant
What to do?
In the first instance, infested cucumber plants should be isolated from other plant neighbors to prevent them from relocating. You can kill the cucumber aphid in an environmentally friendly way with a neem product that you can get in any specialist shop. This acts on the respiratory organs and sticks them together. The parasites suffocate and fall off the plant.
The most natural way to combat them is through natural predators. Ladybugs and lacewings are two examples that feed on aphids, consuming hundreds of them every day. Insecticides should only be used as a last resort.
mildew
powdery mildew
The pseudofungal disease can be recognized by white mold-like deposits that form on the leaves and stems. They leave a slightly sticky feel to the touch. Especially in warm and dry months, the pseudo fungus is particularly common.
The leaves usually turn yellow first and then slowly dry up. Powdery mildew spreads to cucumbers if not combated in time. The fruits wither, contract, and eventually wither before falling off.
powdery mildew on plant leaf
What to do?
If powdery mildew is detected early and the cucumber plant is not too weak, an effective home remedy using soapy water will help.
- make strong soapy water (ideally with natural soap and/or soft soap)
- Pour soapy water into a spray bottle
- Spray the cucumber plant dripping wet from all sides with the soapy water
- Don't forget the underside of the leaves
- For a stronger effect, rub affected parts of the plant with the soapy water
- do not rinse off
- Repeat after three or four days if necessary
Wrong mildew
In contrast to powdery mildew, downy mildew likes cool and damp. Due to the high water requirement of cucumbers, they are affected by downy mildew more often than by powdery mildew.
It can be recognized by the greyish, mealy spots it causes on the underside of the leaves. This forms white-grey mushroom carpets. Brown-yellow spots appear on the upper sides of the leaves as the disease progresses. As a result, the leaves dry up, while the fungus also spreads to the fruit. There it causes stunting, especially of young fruits. In the worst case, the entire cucumber plant can dry up and die.
What to do?
Theoretically, infested Cucumis sativus could still be eaten at the beginning of an infestation. However, since downy mildew can cause allergies, it is important to avoid eating cucumbers from infected cucumber plants. An environmentally friendly and natural, but effective control can be done by spraying horsetail broth.
Winter Horsetail, Equisetum hyemale
This is easy to make yourself and easy to use:
- Collect 1 at 1.5 kilograms of fresh field horsetail (can be found on roadsides and in fields)
- alternatively, 150 grams to 200 grams of dried field horsetail can be used
- cut fresh field horsetail into small pieces
- into a bucket filled with 10 liters of water
- Leave to soak for 24 hours
- then boil the water and let it simmer for about 30 minutes
- Sift the remains of horsetail from the broth
- Let the broth cool
- pour into a spray bottle
- Spray the cucumber plant vigorously from all sides
- If necessary, repeat the process after three or four days