Cucumbers (Cucumis sativus) are relatively undemanding plants to grow, but they can still develop issues. One of the most common problems you might encounter is yellow cucumbers. Yellow cucumber plants and fruits may be due to environmental problems, pests, or diseases. This guide will walk you through figuring out why your cucumbers are yellow and what to do about it.
JOHN GRANEN
The Reasons for Yellow Cucumbers
Yellow cucumbers can be frustrating, but they don’t always mean your plant is in poor health. Even if your cucumbers are yellow due to pests or other problems, solutions are available to help the cucumbers bounce back.
The 1. Overripe Cucumbers
By far, the most common cause of yellow cucumbers is overripe fruit. While most people think cucumbers are ripe when they’re crisp and green, in botanical terms, they are “immature” at this point in their development and aren’t fully ripe. That’s why if you don’t pick cucumbers often, they continue to ripen on the vine, eventually turning a dark, golden-yellow color. When this occurs, cucumbers develop a bitter flavor, mushy texture, large seeds, and tough skin, which makes them unpleasant to eat.
The solution:The best way to avoid overripe cucumbers is to harvest your cucumbers often—ideally every day or two. Cucumbers can ripen quickly, and it’s sometimes hard to see green cucumbers in dense cucumber vines, so you may need to push leaves away when harvesting. You can also prune back some of the vine’s foliage to make it easier to spot cucumbers that are ready to pick.
If you spot overripe yellow cucumbers on the vine, remove them as soon as possible so they don’t sap the cucumber vines of energy. While yellow cucumbers don’t taste as good as green ones, they are still edible and can work in relishes. Alternatively, allow yellow cucumbers to ripen fully on the vine and then harvest them for seeds for next year’s garden.
The 2. Water Stress
Cucumbers are water-loving plants that need regular moisture to grow properly. However, if cucumber vines are over- or under-watered, they can suffer stress and produce yellowed fruit as a result.
The solution:Following a regular watering regimen is important for most garden plants, and cucumbers are no exception. Cucumbers need about 1 inch of water per week to grow properly, but if you aren’t sure your plants are getting enough water, you may want to invest in a rain gauge or test the soil manually with your finger. If the top 1 to 2 inches of soil feels dry, it’s time to water the cucumber vines.
Cucumbers grown in containers dry out more quickly than plants grown in garden beds, so it’s doubly important to stay on top of watering if you keep a container garden. One way to ensure your cucumber plants stay nice and moist is to install a thick 1- to 3-inch layer of mulch around the plants, which slows down soil evaporation rates.
The 3. Nutrient Deficiencies
In addition to needing lots of water, cucumber vines are also heavy feeders, and they can struggle to grow in nutrient-deficient soils. When cucumbers don’t get enough nutrients, their growth can slow, and the vines may become stunted. Beyond this, plants grown in poor soils can also develop discolored leaves and yellow cucumbers.
The solution:Nutrient deficiencies are more likely to develop if you grow cucumbers or other heavy-feeding plants in the same area year after year. One good way to prevent this is to rotate your crops annually and include legumes or nitrogen-fixing cover crops, as these plants naturally replenish soil nutrients.
You can also prevent nutrient-deficient soils by testing your garden soil every few years and amending it if needed. Applying fertilizer and adding an annual application of compost or aged manure to your garden before planting in spring can also provide cucumbers with the nutrients they need to grow correctly.
The 4. Lack of Pollination
Cucumbers produce male and female flowers, and pollinators need to visit both flower types for cucumbers to set fruit. Female cucumber flowers need at least 8 to 12 visits from bees to produce a good-sized cucumber! However, if they aren’t pollinated fully, the immature fruit doesn’t grow correctly and often results in yellow cucumbers before dropping off the plant. If you notice the vines are producing lots of flowers, but the cucumbers are yellowing before they mature, you may be dealing with a pollination issue.
The solution:If your cucumbers are turning yellow due to a lack of pollination, take steps to make your garden more pollinator-friendly. This can include reducing pesticide use and opting for all-natural pest control options, like fruit protection bags and companion planting. You can also increase pollinator activity by growing flowering herbs and plants like marigolds and borage near your cucumber plants to attract beneficial insects.
The 5. Yellow Cucumber Varieties
It may seem obvious, but some cucumber varieties are meant to turn yellow when they ripen. Cultivars like C. sativus ‘Lemon’, C. sativus ‘Boothby's Blonde’, and C. sativus ‘Silver Slicers’ have yellow skins even when they mature. Like green cucumbers, yellow cucumber varieties are usually harvested when they’re a pale yellow color and before their skins turn a deep, dark yellow, which signifies that the fruit is overripe.
Even if you didn’t intentionally plant yellow cucumbers, there’s a chance that seeds were mislabeled or that a stray seed from a yellow cucumber variety found its way into your seed packet. This is particularly likely if you notice a single cucumber vine in your garden produces only yellow cucumbers.
The solution:Enjoy your colorful cucumbers. Yellow cucumber varieties are just as tasty as green cucumbers, and they are often less prone to bitterness as they mature.
The 6. Plant Diseases
Certain plant diseases, such as cucumber mosaic virus, fungal issues, and leaf spot, can also result in yellow cucumbers. However, these plant diseases also affect the cucumber vine itself. Many of these diseases are spread by insect vectors, including the cucumber beetle, and affected plants will often develop spotted, wilted, or otherwise damaged leaves in addition to their yellowed fruit.
The solution:Most plant diseases that cause yellowing in cucumbers are difficult to cure, so treatment is usually focused on prevention. Fungal issues are often caused by poor airflow and wet cucumber leaves, but you can reduce fungal spread by watering your plants only at the soil line and pruning away extra leaves to increase air circulation. Diseases that are spread by insect vectors can be prevented with organic pest control methods and annual crop rotation. Choosing disease-resistant cucumber cultivars is another effective way to keep plant diseases out of your garden.
The 7. Pest Issues
Cucumber pests can transmit plant diseases that cause yellow cucumbers, but some can also damage them and reduce fruit quality. Different pests damage cucumbers in different ways, but commonly, these destructive insects leave behind a characteristic stippling pattern on plant leaves and fruit as they feed. Some of the most common cucumber pests that damage cucumbers include the striped cucumber beetle, thrips, and spider mites.
The solution:Companion planting with aromatic herbs and flowering plants can naturally repulse many garden pests or attract beneficial insects that feed on nuisance pests. You can also keep pests off your cucumbers by installing floating row covers, but you need to hand-pollinate the cucumbers if you go this route. Organic insecticidal soap and neem oil sprays can also treat many pest infestations, and they’re much safer to use around the garden than chemical pesticide alternatives.
What to Make with Your Fresh Cucumbers
Use up your cucumbers in more ways than simple salads or as a crudité. A staple of afternoon tea for generations, cucumber sandwiches are a light nibble to enjoy with iced tea or hot, depending on your preference. Skip the cole slaw with grilled burgers and make this Cucumber Radish Slaw for a change of pace. Top a pork stir fry with cucumbers for a tasty Asian-inspired meal you'll want on repeat. If you're set on a salad, try this smashed cucumber version for a spicy alternative to the usual green salad. Make sure you're storing your cucumbers the right way for maximum flavor and freshness.