Are you perplexed as to why your cucumber plant is not growing? The most common problems that lead to stunted growth and lack of fruit set for cucumber plants relate to inadequate soil conditions, poor watering, lack of nutrients, and non-optimum weather conditions.
Lack of fruit set or fruit that is not fully developing can be caused by lack of pollination, improper watering, and incorrect plant spacing.
Let’s look at these problems individually so that you can diagnose them and find some solutions.
1. Inadequate Soil Conditions
Cucumbers need soil that is rich in nutrients and at a pH of around 7. If the soil is too acidic or alkaline, the plants won’t be able to take up the necessary nutrients for adequate growth.
Therefore, you need to check the pH of the soil and amend it if necessary. For this, you’ll need a soil testing kit that you can purchase from your local garden center.
Adding plenty of mature organic compost before planting your cucumbers is one way of ensuring that the soil conditions are adequate for good growth. This will also provide your plants with plenty of nutrients to sustain their growth.
However, if your cucumbers are already planted and the soil is far from a neutral pH of around 7, here’s what you can do:
- Add some ground agricultural limestone to the soil around your plants and water in. This will increase the pH level and reduce the acidity of the soil.
- You can also use wood ash to increase the pH of the soil but take care not to get any onto the plants and keep away from the roots.
- To lower the pH of alkaline soils, you can add some aluminum sulfate which works almost instantly. Additionally, sulfur can also be used to lower the pH of the soil, but this takes a little longer to work.
You can purchase these products at your local garden center but make sure that you follow the instructions on the pack so that you add the correct amount.
Additionally, adding some organic animal manure or bonemeal to the soil around your plants will provide plenty of nutrients that the plants can use as well as amend the soil gradually over time.
2. Poor Watering
Cucumber plants need plenty of water to grow well. In fact, these plants don’t like the soil drying out at all. However, they don’t do well in waterlogged soils either.
As long as you have well-drained soil, your cucumber plant should receive at least 1 inch of water every week. Because cucumbers grow in the warmer months, this may require daily watering when the weather is very hot.
You can also add a layer of mulch over the soil around the plants to stop evaporation and keep the moisture in the soil. Use organic mulch such as straw or hay.
Lack of water not only stunts the growth of your plant but will also affect the fruit quality. Plants that are allowed to dry out will produce poorly formed fruit, and the fruit will also be bitter in taste.
The best way to ensure that your cucumber plant is getting enough water is to install a drip system or use a soaker hose. Both these irrigation systems will direct water down to the roots of the plant and not onto the leaves. It’s important to try and keep the leaves dry to avoid fungal problems such as powdery mildew.
Always remember to check the moisture level in the soil before watering. You can do this by pushing your finger into the soil for about an inch or two. If the soil feels dry, then it’s time to water. Alternatively, you could invest in a moisture meter that checks the moisture level in the soil.
It’s far better to water the soil deeply rather than just giving it a light sprinkle. You should aim to water enough so that the water will reach down six inches into the soil. This is where most of the roots will be growing and ensures that these roots get the water that they need to sustain healthy plant growth.
3. Lack Of Nutrients
Cucumber plants need plenty of nutrients to grow well. This is precisely why you should add lots of compost to the soil before planting them. However, it’s not too late to provide your plants with a good feed to encourage them to grow vigorously.
If you notice that the leaves of your cucumber plant are a little yellow, this indicates that they lack in vital nutrients. In general, you should supply your plant with a good dose of liquid fertilizer at least once a month.
Choose a fertilizer that is high in phosphorus and potassium if you want lots of fruit. Too much nitrogen will promote plenty of vine growth but not enough fruiting. Check the N:P:K level on the pack and look for one that is similar to this ratio – 3:4:6. This is three parts nitrogen (for green growth), four parts phosphorus (for good root formation and flowering, and six parts potassium (for good fruit production).
If you live near the coast and are able to gather some dried seaweed, you can lay this on the soil between the plants. This will provide lots of nutrients as it breaks down.
Additionally, consider spreading some organic animal manure or bonemeal around your plants, as this will stimulate plenty of growth once it gets down into the soil where the roots are.
4. Weather Conditions
While you can’t control the weather, you can ensure that you plant your cucumbers at the right time. Cucumbers are a warm-season crop and need to be grown when temperatures are between 65 to 75 degrees Fahrenheit (18 to 24 degrees Celsius). Therefore, you should not plant your cucumbers until the soil temperature is above 60 degrees Fahrenheit (16 degrees Celsius).
Another thing to remember is that cucumbers really don’t like having their roots disturbed too much during planting. Therefore, growing them from seed is one of the best ways to avoid this. However, if you live in a cold climate and only have a short optimum growth time for your cucumbers, you can start them indoors but plant each seed into an individual peat pot. This way, you can plant the entire pot into the ground without disturbing the roots at all.
Conversely, if you do decide to use transplants, make sure that you nurture them a little in the first couple of weeks to reduce transplant shock. Feed them with some diluted organic liquid fertilizer, provide them with some shade and keep them well-watered.
Cucumbers also grow best when in full sun. In fact, your cucumber plant should receive around 8 hours of direct sunlight every day. However, if the temperature is likely to get above 90 degrees Fahrenheit (32 degrees Celsius), then you should give your plants some afternoon shade.
You can do this by installing a shade structure above your plants or placing larger plants in pots nearby, where they’ll offer some shade to your cucumbers.
Another issue that too much hot weather can produce is an overproduction of male flowers and a lack of female flowers. This happens because the plant is under stress, and it takes less energy to produce male flowers than female ones. When this happens, there’s obviously going to be a lack of fruit production.
To help combat this stress because you can’t control the weather is to ensure that your plants are getting plenty of moisture at the root level and that you’re providing afternoon shade.
5. Incorrect Plant Spacing
For optimum growth, it’s important that your cucumber plants are spaced correctly. Cucumber plants should be spaced around 8 to 12 inches apart. This allows enough room for the plants to grow without being too crowded.
It also allows enough space for good airflow, which will limit the growth of fungal diseases and bacterial wilts.
On the other hand, make sure that your plants aren’t spaced too far apart as this can limit pollination and, therefore, fruit production.
6. Lack Of Pollination
If your cucumber vines seem to be growing well but not producing any fruit, then it could be because the plants aren’t being pollinated. For fruit to develop, each flower on the cucumber plant needs to be visited by a pollinating insect several times in order for the fruit to grow properly.
When this happens, it means that there are not enough bees and other pollinators visiting your garden. It’s important to remember not to spray any insecticides around your vegetable garden as these will kill pollinators such as bees.
You can help to attract more bees to your garden by planting lots of flowering annuals and herbs among your vegetables. These include oregano, basil, dill, sunflowers, zinnias, and lavender.
In the meantime, though, you might need to do some hand pollinating to encourage fruit set. The first thing you need to do is distinguish between male and female flowers. The male flowers are produced first on normal stems, while the female flowers will have a swollen part at the base where the flower meets the stem.
Using a small paintbrush or cotton swab, you need to transfer some of the pollen from the male flower onto the stigma of the female flower. You could also remove the male flower and shake it above the female flower, ensuring that the pollen drops onto it.
Another thing to remember if you want lots of fruit on your cucumber plant is to pick each fruit once it’s the right size. This will encourage the plant to put more energy into additional fruit production. If you fail to pick the ripe fruit, then the plant will stop producing more because it thinks that its reproduction cycle is complete.
Also, when picking your fruit, don’t just pull them off the vine. Use a sharp knife or secateurs to cut them off instead. This will ensure that you don’t damage the rest of the vine.
7. Not Providing A Climbing Frame Can Also Limit Growth
Cucumber plants are vines and generally prefer something to grow over and cling to. Therefore, you should provide your plant with a climbing frame or trellis. You’ll notice that your plants send out long tendrils that curl around supports.
Giving your plants a climbing frame encourages them to keep growing up and over the frame. This is also a good way to keep the developing fruit off the ground and provides plenty of airflow around your plants.
8. Fungal Diseases Can Limit Plant Growth
Another problem that can stop your cucumber plant from growing is the presence of fungal diseases such as powdery mildew. This disease appears as a white powder-like substance on the leaves of your plant.
If the disease is not heavily infesting your plants, then it’s just a cosmetic problem. However, if many of the leaves on your plant are covered in powdery mildew, then this can inhibit photosynthesis and, subsequently, plant growth. You see, if the plant can’t photosynthesize, then it can’t produce the food necessary for its growth.
Powdery mildew is not that easy to get rid of once it has infected your plants, but spraying with a fungicide may limit the spread. There are also numerous home remedies that you can try that include regular household products such as baking soda and dish detergent.
However, the best idea is to prevent it from infecting your plants in the first place. You can do this by purchasing resistant varieties and ensuring that you keep the plant leaves as dry as possible. This is because most fungal diseases will thrive on wet leaves.
9. Watch Out For Bacterial & Viral Diseases
Bacterial diseases such as fusarium wilt and viruses such as mosaic virus will not only stunt the growth of your plant but will end up killing it as well. Unfortunately, these types of diseases are mostly not curable, so it’s important to watch out for any signs of them so that you can remove the infected plant to prevent the spread to other healthy plants.