7 Causes Why Your Cucumbers Are Turning Yellow

Cucumbers are one of the vital prolific backyard greens once they’re wholesome. They will shortly climb over our heads and ship out kilos of crunchy cukes every week. And what a deal with that is!

Nevertheless, cucumber vegetation are additionally inclined to varied environmental issues, illnesses, and pests. Even in case you don’t know what’s plaguing your cucumber vegetation, watching the inexperienced leaves flip yellow is an apparent solution to inform that one thing has gone improper. However what, precisely?

Yellow leaves can point out quite a lot of issues, together with points with water, gentle, and vitamins. I’ll cowl seven explanation why your cucumbers could also be turning yellow so you possibly can treatment the reason for the yellow leaves.

Too A lot Water

As gardeners, we frequently love our vegetation to demise. A technique this occurs is by watering our vegetation an excessive amount of. Whereas cucumber vegetation want water to develop and stay wholesome, an excessive amount of water can forestall the roots from taking on vitamins and finishing fuel change. It could additionally enhance the chances that the vegetation develop fungal illnesses.

If you happen to overwater your cucumber plant, the roots will stay sitting in water. This stresses the plant and limits its potential to finish essential processes like photosynthesis. If the roots turn into rotten, they’re unable to take up the mandatory vitamins and water. This stress finally results in yellow leaves.

So, how a lot water is an excessive amount of? Usually, the soil your cucumbers are rising in ought to stay moist however not soaking moist. Whenever you’re figuring out how usually to water your cucumber vegetation, you need to have a look at and take into consideration the next elements:


Lush cucumber vines and broad leaves glisten under a gentle rain shower; their green hues refreshed and enhanced by droplets of water.
Skip watering if the soil is moist six inches deep.

It most likely appears apparent, but when the soil is moist from rain, you most likely don’t need to water your cucumber plant. I say most likely as a result of the quantity of rainfall determines whether or not or not your vegetation obtain sufficient moisture. A brief and mild rain could make the soil floor seem moist, however the soil should still be dry 4 or six inches underground. Subsequently, don’t assume a moist soil floor means you possibly can skip watering.

A half inch or extra of rain often means you possibly can skip your deliberate watering. If you happen to’re uncertain in case your vegetation acquired sufficient water, you possibly can dig right into a portion of the bottom a foot away out of your cucumber. Soil that’s moist six inches underneath the floor is moist sufficient to skip watering.


A cucumber rests on rich, dark soil, amidst a tangle of lush vines and verdant leaves.
Transpiration charges lower with cooler temperatures and enhance with larger temperatures.

You know the way we have to drink extra water when it’s scorching outdoors? Nicely, cucumber vegetation are the identical approach. As temperatures rise, cucumber vegetation cool themselves by means of a course of known as transpiration. Throughout transportation, vegetation open leaf pores known as stomata to launch water vapor. The conversion of water from liquid to gaseous type cools the plant.

Low temperatures coincide with lowered charges of transpiration. Moreover, excessive temperatures lead water to evaporate from the soil extra shortly. Subsequently, vegetation require much less water throughout cooler instances of the yr and extra water throughout scorching instances.


Yellowing cucumber leaves in foreground, contrasting against deep green foliage in the background.
Water your vegetation extra continuously throughout dry durations in comparison with humid ones.

Humidity additionally performs an enormous half in transpiration charges; vegetation lose much less water by means of their leaves if there’s already quite a lot of water vapor within the air. Nevertheless, dry air hastens transpiration. Subsequently, plan to water your vegetation extra throughout dry durations than throughout humid durations.

Soil Kind

Hand holding sandy soil with scattered grains, under soft sunlight.
Clay and natural matter enhance water retention.

Simply take into consideration a sandy seaside and a clay pot to grasp how soil kind impacts water motion. As waves wash over a seaside, the water shortly infiltrates the floor and percolates into the bottom. The identical factor occurs in case you occur to spill a drink. Nevertheless, in case you spill water on an unglazed clay pot, the water will type a puddle earlier than slowly transferring by means of the clay. The one distinction between sand and clay is the scale of the soil particles.

Since sand consists of bigger particles, there’s extra air area that water can journey by means of. Clay’s small particles can pack intently collectively, resulting in small air areas and slowed water motion. Since soil comprises a mix of clay, silt, sand, and natural matter, the quantity of every materials impacts water motion.

Usually, sand will enhance soil drainage and encourage you to water your vegetation extra continuously. Clay and natural matter enhance the water-holding capability of the soil, so that you gained’t need to water your soil as usually.


Green cucumber plants growing in neat rows, supported by a dense layer of protective mulch.
Thicker layers of mulch are extra environment friendly than thinner ones.

Including mulch to the floor of the soil limits evaporation. Subsequently, you possibly can plan on watering mulched soil much less continuously than you’d water soil with out mulch. The kind of mulch doesn’t matter, however a thick layer of mulch will hold the soil moister than a skinny layer of mulch.

Not Sufficient Water

A cucumber plant with yellowing leaves emerges from dark, cracked soil.
Be sure that cucumber vegetation obtain deep however rare watering.

Similar to an excessive amount of water could cause an issue for cucumber vegetation, so can too little water. Cucumber vegetation have a big leaf floor, so that they lose quite a lot of water by means of transpiration. Plus, for the reason that fruits have a excessive water content material and develop shortly, cucumber vegetation want quite a lot of water to supply wholesome and crunchy cukes.

In case your cucumber vegetation don’t obtain sufficient water, they’ll wilt. An absence of water additionally causes nutrient deficiencies since vegetation depend on water to maneuver vitamins from the soil all through the plant. If vegetation don’t obtain sufficient water, they could start to indicate indicators of nutrient deficiencies even when sufficient vitamins are current within the soil. Yellow leaves are one of many indicators.

Purpose for deep, rare watering reasonably than frequent, shallow watering once you water your cucumber vegetation. One of these irrigation will encourage the vegetation to develop deep and powerful root programs, and it’ll additionally assist guarantee all components of the roots obtain water.

The best watering schedule will depend on the elements I listed above: temperature, humidity, soil kind, rainfall, and so on. Nevertheless, most cucumber vegetation require deep watering three to 4 instances per week. If you happen to discover it troublesome to recollect to water your vegetation, you possibly can arrange a drip irrigation system and place this method on a timer. That is additionally an incredible irrigation methodology in case you journey continuously. If you happen to choose handy water your vegetation, ensure to water on the base to keep away from getting the leaves moist.

Not Sufficient Vitamins

Cucumber vegetation require 16 completely different vitamins to thrive. Since they receive three of those vitamins (oxygen, hydrogen, and carbon) by means of water uptake and fuel change, you solely want to provide the remaining 13. Deficiencies in any of those vitamins can result in points with nitrogen fixation, chlorophyll manufacturing, illness resistance, and extra.

Whereas cucumbers can lack any of the 13 vitamins, some nutrient deficiencies are extra widespread than others. An absence of the next vitamins usually exhibits up as yellow leaves.


Yellowing cucumber surrounded by lush green leaves, showing signs of nutrient deficiency.
Vegetation with nitrogen deficiency show gentle inexperienced leaves that progressively flip yellow.

Nitrogen (N) is among the major plant vitamins, together with potassium (Ok) and phosphorus (P). Vegetation use nitrogen to type proteins, construct the genetic materials RNA and DNA, take up vitamins and water, and type chlorophyll. Nitrogen is a cell nutrient, which suggests it may well readily transfer all through the plant. Subsequently, you’ll discover deficiency signs in older leaves first.

Cucumber vegetation which can be nitrogen poor start to develop gentle inexperienced to yellow leaves. Over time, these leaves turn into increasingly yellow. Whereas the veins could stay inexperienced within the early levels of nitrogen deficiency, they finally flip yellow. Different indicators of nitrogen deficiency embody stunted progress and brief stems.

Some natural nitrogen sources embody blood meal, feather meal, alfalfa meal, and high-nitrogen compost. In case your vegetation want nitrogen ASAP, you possibly can foliar feed your cucumber vegetation with a liquid fertilizer like fish emulsion.


 Cucumber plant leaves showing initial signs of yellowing caused by potassium deficiency.
Search for signs equivalent to yellowing older leaves with brown edges.

One other major nutrient, potassium (Ok), acts as a communicator inside vegetation. Though it doesn’t make up molecules like proteins and carbohydrates, it helps transfer water and vitamins, activate enzymes, and regulate the manufacturing of ATP, an vitality switch molecule. Potassium uptake is very depending on soil moisture, so this nutrient deficiency usually coincides with underwatering, compacted soil, and different elements inhibiting the plant’s water uptake.

Indicators of potassium deficiency embody yellow older leaves with brown edges and/or brown spots. Different indicators embody brief stems and an general weak plant.

If you happen to suspect potassium-deficient soil, add an natural supply of potassium, like sunflower hull ash or potassium sulfate. You must also guarantee your vegetation are rising in unfastened soil and that you just’re including the right amount of water.


Yellowing cucumber leaves with brown edges, indicating a magnesium deficiency affecting plant health and growth.
Older leaves are the primary to yellow, with patchy discoloration spreading to youthful leaves.

Magnesium (Mg) is a secondary plant nutrient that helps with cell division, cell respiration, and enzyme activation. It’s additionally a key element of chlorophyll molecules. Subsequently, vegetation that don’t have sufficient magnesium usually develop yellow leaves.

The yellowing begins out in older leaves and takes on a patchy look. The spots between leaf veins turn into dotted with yellow, brown, and even pink hues. Over time, this discoloration spreads throughout leaves and to youthful leaves.

Some natural sources of magnesium embody rock dusts like azomite and dolomite.

Not Sufficient Mild

Cucumbers with bumpy skins hanging on vines, surrounded by lush green leaves that create a natural canopy.
Inadequate gentle causes vegetation to supply much less chlorophyll.

Cucumbers thrive in full solar and can undergo in the event that they don’t obtain sufficient gentle. Whereas the vegetation can develop with solely six hours of direct gentle, they desire eight or twelve hours of sunshine. In the event that they don’t obtain sufficient gentle, they gained’t have the vitality they should develop, combat off illness, produce flowers, and extra.

Vegetation that don’t obtain sufficient gentle have issue producing chlorophyll, the pigment that turns vegetation inexperienced. If vegetation have much less chlorophyll than they want, they’ll start to yellow. One of these yellowing usually happens all through your entire leaf reasonably than simply at leaf margins or in between leaf veins.

Cucumber vegetation that want extra gentle usually seem stunted, and their leaves are additionally smaller than common. In case your plant exhibits both or each of those indicators, there’s an excellent probability it wants extra gentle.  Whereas it’s arduous to maneuver your cucumber plant as soon as it’s within the floor, hold this info in thoughts for future plantings.


Cucumber vegetation are inclined to quite a lot of illnesses, lots of which may result in yellow leaves. Listed below are a couple of widespread cucumber illnesses that may trigger yellow leaves.

Downy Mildew

Cucumber leaves display noticeable yellow patches, indicating an infection of downy mildew.
Efficient prevention methods for downy mildew embody correct plant spacing.

Downy mildew impacts quite a lot of vegetation, together with cucumbers. It’s attributable to a water mildew and is probably to happen throughout cool, humid situations. Subsequently, it usually seems within the spring or early summer time.

The primary indicators of downy mildew are yellow, angular spots between the leaf margins. These spots finally unfold and switch brown, and finally, your entire leaf turns brown and dies.

Since downy mildew is troublesome to deal with, prevention is the very best technique. Correct plant spacing and backside watering will help hold leaves dry, and deciding on downy mildew-resistant varieties decreases the probabilities of plant an infection.

Cucumber Mosaic Virus

A potted cucumber plant with broad, green leaves visibly affected by cucumber mosaic virus, showing mottled yellow patterns and slight curling.
Take away contaminated vegetation and go for disease-resistant varieties in your backyard.

If you happen to discover your cucumber leaves look mottled with patches of yellow, they could have turn into contaminated by the cucumber mosaic virus. This virus causes stunted progress and leaves that turn into patterned with shades of yellow, gentle inexperienced, and darkish inexperienced. Sadly, this illness can’t be cured as soon as it strikes your plant.

Because it overwinters in plant materials, ensure to take away any contaminated vegetation out of your backyard. You too can search for disease-resistant varieties.

Angular Leaf Spot

Sunlit cucumber plants display symptoms of angular leaf spot, characterized by their yellowing surfaces and the presence of scattered holes across the leaves.
This bacterial illness leads to dry brown spots with yellow halos on leaves.

This bacterial illness causes cucumber leaves to develop dry brown spots surrounded by a yellow halo. It’s probably to happen throughout scorching and humid summers. You’ll be able to forestall this illness through the use of drip irrigation and selecting resistant varieties. 

Pest Injury

Be careful! You’re not the one one who finds cucumbers tasty. Quite a few tiny pests feed on insect leaves, resulting in holes and discoloration. Sometimes, pests will solely trigger yellowing on the sections of cucumber leaves they’ve attacked. Maintain a watch out for the next cucumber pests.

Squash Bugs

A close-up of a brown squash bug showcases its detailed exoskeleton as it rests on a yellowing leaf.
Management squash bugs by manually eradicating them.

Though squash bugs are greatest recognized for attacking zucchini and butternut squash leaves, they’ll feed on any member of the cucurbit household. And that features cucumbers. These brown bugs use their piercing mouthparts to stab cucumber leaves and drink their sap. This leads to gentle inexperienced or white spots the place the bugs ate. If the bugs assault sufficient of the plant, leaves could flip brown and die.

If you happen to see squash bugs, take away them by hand. You must also look out for clusters of sunshine yellow, rectangular eggs on the undersides of the leaves. Another choice is to spray the bugs with neem oil or insecticidal cleaning soap.

Spider Mites

A close-up of a cucumber leaf covered in intricate webs spun by numerous tiny spider mites.
Spray with water to take away spider mites from the plant.

These tiny mites go away behind spiderweb-like constructions, therefore their widespread title. Though spider mites are lower than an eighth of an inch lengthy, they will shortly multiply and harm vegetation. They use their piercing-sucking mouthparts to poke small holes in cucumber leaves after which drink the sap. This feeding finally results in small yellow or gentle inexperienced dots referred to as stippling.

One solution to take away spider mites is to spray them off the vegetation with a gradual stream of water. You too can spray the pests with insecticidal cleaning soap or neem oil. So long as you deal with the pests shortly after they seem, your cucumber plant will get well.

Compacted Soil

Cracked and compacted brown soil, indicating severe dryness and a lack of moisture.
Bettering soil aeration earlier than planting prevents nutrient uptake points.

If you happen to’re watering your vegetation the right quantity, offering them with the suitable vitamins and lightweight, and maintaining them illness and pest-free, it’s simple to imagine every little thing is sweet. But when cucumber leaves nonetheless look yellow, you could be coping with compacted soil. When the soil is compacted, water has a tough time flowing, and the vegetation’ roots have issue finishing fuel change and rising.

When cucumber vegetation have weak root programs, they’ve issue taking on water and vitamins. This may result in yellow leaves, stunted vegetation, and different issues. It’s arduous to treatment compacted soil as soon as your vegetation are rising, so strive to decide on a well-aerated and well-draining location earlier than planting. If you could loosen your soil, you are able to do so by gently lifting it with a digging fork or shovel. Mixing in completed compost additionally helps enhance soil construction and plant well being.

Remaining Ideas

In case your cucumbers are turning yellow, determining the reason for the discoloration is your first step. When you’ve decided the trigger, you possibly can work to treatment the issue or at the very least forestall it the following time round.

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