Courgettes (Zucchini) are a satisfying crop to grow and are technically a fruit.
They are the same family as squashes, melons, pumpkins and cucumbers.
Unfortunately they can sometimes wither and die on the vine, which can be very disheartening.
Here we aim to answer the question – Why are my courgettes dying?
Your courgettes could be dying because of soil or environmental conditions, inadequate pollination, nutrient deficiencies or incorrect hydration. Also, pests, bacteria and fungus can affect the health of growing courgettes.
Incorrect Soil Conditions
A healthy soil is the foundation of a thriving garden.
Courgettes require well-draining soil that is rich in nutrients for the best growth.
If the soil is compacted or lacks proper drainage, water may accumulate around the roots, leading to root rot.
Also, nutrient deficiencies can weaken plants, making them susceptible to diseases and stress.
How to fix:
You can carry out a soil test to find out the pH level and nutrient content of your soil.
Enrich the soil with organic matter like compost or well-rotted manure to improve the nutritional value.
If your soil is clay, or heavy material that compacts, consider adding some sand or grit to improve drainage.
Ensure proper spacing between plants to prevent overcrowding and competition for nutrients.
Courgettes will spread out quite a lot, and will need up to a metre space from the next plant.
Too Much, Too Little or Irregular Watering
Overwatering or underwatering can both be a problem for courgette plants.
Overwatering can suffocate the roots and encourages fungal growth, while underwatering leads to stress and nutrient imbalances.
Both situations weaken the plant’s immune system, making it more susceptible to diseases and pests.
How to fix:
Water the plants consistently and deeply, ensuring the soil is moist but not waterlogged.
Use mulch to retain moisture and prevent the soil from drying out quickly.
A drip irrigation system can provide consistent, even watering.
Pest Infestations
Insects such as aphids, squash bugs, and cucumber beetles are known for attacking courgette plants.
They feed on the plant’s sap which can weaken its structure and spread diseases.
Signs of insect infestations include holes or discoloured speckles in foliage, distorted growth and scarring.
Slugs and snails can munch on the fruit, and if you have larger bite marks on your courgettes then it could even be mice.
How to fix:
Monitor your plants regularly for signs of pests.
Encourage natural predators like ladybugs and parasitic wasps by having a garden that promotes biodiversity.
You can use neem oil to control insect populations.
Introducing companion plants like marigolds can also help deter insects.
For larger pests such as slugs, snails and mice you can use a net over your courgette plants to minimise access, just make sure there is adequate airflow.
Disease
Various fungal, bacterial, and viral diseases can affect courgette plants.
Powdery mildew, downy mildew, and bacterial wilt are common pathogens that lead to yellowing leaves, stunted growth, and overall plant decline.
How to fix:
Choose disease-resistant varieties when planning and planting.
Maintain proper spacing between plants to promote air circulation and reduce the spread of disease.
Regularly clear decomposing plant matter from around the base of the plant.
Remove and destroy any infected plant material to prevent the disease from spreading.
Water at the base rather then over the leaves, as wet foliage can encourage fungus to form and spread.
Nutrient Deficiencies
Courgette plants need a balanced supply of essential nutrients, including nitrogen, phosphorus, and potassium.
Not enough, too much, or the wrong nutrients can result in poor growth, yellowing leaves, and overall plant weakness.
Blossom End Rot is caused by not enough calcium getting to the plant, however usually this is due to insufficient watering (so the calcium cannot be absorbed) rather than your soil being calcium deficient.
How to fix:
If your soil is poor, fertilise the plants with a balanced, slow-release fertiliser that provides essential nutrients.
Keep an eye on your plants for signs of nutrient deficiencies and adjust accordingly.
Water the plants consistently, making sure the soil is moist but not waterlogged. This will allow the courgettes to regularly access the nutrients and minerals in the soil as they need it.
Inadequate Pollination
Courgettes need proper pollination for fruit development.
If pollinators like bees are few or if weather conditions are unfavorable, the fruit may not fully develop, leading to plant stress.
What happens when a courgette is not pollinated properly?
The courgette vine has separate male and female flowers. Bees and other pollinators fly between them and deposit the male pollen from the stamen onto the female pistil. The female flowers need a good amount of male pollen to become fertilised and produce fruit. If a female flower is not visited by the pollinator it will die off without producing a fruit. If the female flower is only visited only once or twice and gets only a small amount of pollen, the fruit will start to develop but then become yellow or bulbous, it will then decompose and die off.
How to fix:
Encourage lots of pollinators by planting pollinator-friendly flowers nearby.
If the weather is cold and there are not many bees about, consider hand-pollinating the plants by transferring pollen from male to female flowers using a small brush or cotton swab.
There are some varieties of courgettes that are self pollinating – no insects required!
One such variety is the brilliantly named “Sure Thing”
Environmental Stress
Extreme weather conditions, such as heatwaves, storms or sudden temperature fluctuations, can stress courgette plants.
This stress weakens the plants and makes them more likely to suffer from diseases and pests.
How to fix:
Provide shade during hot or windy periods, and consider using row covers or cloths to protect plants from sudden temperature changes.
Water the plants adequately during periods of heat stress.
Final Thoughts
Courgettes are one of my favourite crops, they are fairly easy to grow and you get a great yield.
They can occasionally suffer from the ailments listed above, but by being aware of potential issues and addressing them quickly, your courgette health can be preserved.
If you are having any issues with courgettes that have not been covered, then drop me a message and I will do my best to help.
