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Identifying and solving cucumber plant problems

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Cucumbers are one of the most-loved vegetable garden crops, trailing closely behind tomatoes and peppers on the favorites list of many gardeners. Cucumbers are easy to plant, delicious, and they’re prolific producers. But even seasoned growers have cucumber plant problems pop up from time to time. In this article, I’ll share some of the more common cucumber growing troubles and introduce some easy organic solutions.

Common cucumber plant problems

Planting cucumbers from seed instead of transplants can help limit transplant shock.

Plant cucumbers from seed whenever possible to limit transplant shock.

Poor planting techniques stunt growth

Cucumbers are easy to grow from seeds sown directly into the garden, but for northern gardeners with short growing seasons, it may help give you a jump on the season to plant transplants out into the garden, rather than seeds. The trouble is that cucumber plants don’t like to have their roots disturbed and commonly suffer from transplant shock. When struggling with this physiological disorder, cucumber transplants show signs of delayed growth and development, negating the timing benefits of planting young seedlings, rather than planting seeds.

To remedy this common cucumber issue, plant seeds directly into the garden rather than transplants. If you live in the north, select a short-season, fast-maturing variety, such as ‘Patio Snacker’ or ‘Straight 8’. If you feel you must plant transplants, try not to disturb the roots at all when planting the seedlings, or start them in plantable peat pots so you don’t have to disturb the roots at all. Also be sure to pamper the seedlings for the first week or two after planting them into the garden. Use a diluted liquid organic fertilizer, cover them with shade cloth for a few days, and make sure they receive adequate water.

Lack of pollination affects fruit set

Sadly, lack of pollination is one of the most common cucumber plant problems these days. If your cucumber fruits (yes, botanically speaking, cucumbers are fruits, not vegetables) are not fully formed or have an end that’s nothing more than a tiny nub, poor pollination is likely to blame. Each flower must be visited by a pollinator many, many times in order for the fruit to fully form. The more pollinators you have around, the better.

Do not use pesticides in the vegetable garden; even certain organic pesticides can affect bees. Increase the number of pollinating insects in your garden by inter-planting your edible crops with lots of flowering herbs and annuals, such as sunflowers, oregano, basil, zinnias, dill, and black-eyed Susans.

Deformed or stunted cucumbers are often the result of poor pollination. They are one of several common cucumber plant problems.

Cucumbers with a stubby or deformed ends are a sign of poor pollination.

Lack of water limits cucumber vine growth

Cucumber vines are thirsty, and they’ll let you know if they don’t receive ample irrigation water. If your vines wilt or are growing more slowly than you’d like, lack of sufficient water could be to blame. Like all plants, cucumbers grown in the ground prefer to receive a deep, penetrating soaking of their root zone once or twice a week, rather than light, shallow irrigation every day.

Cukes grown in the ground should be mulched with a layer of shredded leaves or straw to stabilize soil moisture. Container-grown cukes, will need to be deeply watered every day during hot summer weather. Do not do “splash and dash” irrigation that barely gets the leaves and soil wet. Target the hose right onto the soil and allow it to run through the soil and out the drainage hole in the bottom of the pot.

Water vines properly for best fruit set.

Drip irrigation tubes set at the base of cucumber plants helps target irrigation water.

Poor nutrition affects cucumber plant health

Cucumber vines are heavy feeders. If your vines are pale green or yellow, especially the older leaves, they may need a nutritional boost. In the garden, adding a few inches of compost in the spring should provide all the nutrition your vines need. But, if you find them yellowing as the summer progresses, feed the plants with a liquid organic fertilizer once a month. You can also work organic granular fertilizer into the planting beds prior to planting the seeds but only if a soil test tells you its necessary. Too much nitrogen yields long, green vines with few flowers or fruits.

Container-grown cucumbers will need to be regularly fed with a liquid organic fertilizer. Be sure to use a high quality potting soil when planting them. Here’s the recipe I use for making my own potting soil.

Trouble growing cucumbers? Healthy cucumber vines in a garden are well-fed and watered.

Feed plants with high quality compost and organic fertilizer when necessary .

Powdery mildew limits cucumber growth

If the leaves of your cucumber plants appear to be dusted in talcum powder, powdery mildew is the cause. This is one of the most common cucumber plant problems gardeners deal with. Thankfully, it’s more of an aesthetic issue, though heavy mildew limits photosynthesis and growth. There are many different species of this fungal organism that live on the leaf surface.

Plant cucumber varieties with a known resistance (the disease resistance-code PM will be found on the seed packet or in the seed catalog description), such as ‘Eureka’, ‘Jackson’, and ‘Transamerica’. Do your best to keep the foliage dry when watering your garden. Most fungal diseases thrive on wet foliage. Water in the morning to give the plants plenty of time to dry before nightfall. Powdery mildew on cucumbers is managed with organic fungicides based on Bacillus subtilis (Serenade™) or bicarbonates (including Green Cure™ and Bi-Carb®).

Cucumber beetles are one of the most difficult cucumber growing problems

Depending on where you live, you have one of two different species of cucumber beetles hanging about your garden: the striped cucumber beetle and the spotted cucumber beetle. Both species feed on all members of the cucurbit family. The adult beetles make ragged holes in the leaves and flowers, while the larvae feed on plant roots.

Both striped and spotted cucumber beetles attack plants.

Striped and spotted cucumber beetles feed on plants and spread disease.

Your first line of defense is to plant beetle-resistant varieties. Since they’re attracted to a particular compound found in the leaves of cucumber plants, varieties with low levels of these compounds are best. ‘Saladin’ and ‘Gemini’ are two great cucumber beetle-resistant varieties. Cover the plants with floating row cover from the time the seeds germinate until the plants come into flower to keep the beetles at bay.

You’ll also have great success trapping the beetles by placing yellow sticky cards just above the plant tops. For large cucumber plantings in rows, run a strip of yellow caution tape coated in a non-drying glue, such as TangleTrap, on stakes just above the plant tops. Sadly, you may accidentally trap some “good bugs” with this technique, too, but pest insects are more attracted to yellow than most pollinators are. Cucumber beetles love Blue Hubbard squash, so plant a few vines of this winter squash to lure the beetles away from your cukes.

Surprisingly, cucumber beetles are also great pollinators of cucumber plants, so most of the time I let them be. They seldom cause significant damage to the plants from their feeding activities — unfortunately, however, cucumber beetles transmit deadly bacterial wilt, which brings us to one of the biggest cucumber plant problems of all….

Bacterial wilt kills cucumber plants

This pathogen affects all members of the cucumber family, including cukes, muskmelons, pumpkins, and squash. The first sign of infection is wilted and drying leaves, sometimes seemingly overnight. It’s extremely disheartening to have healthy, prolific vines one day and then wilted and dead vines a few short days later.

An easy to way to confirm that bacterial wilt is the cucumber issue you’re dealing with, is to cut a wilted stem off at the base and touch the cut with your fingertip. If white, thin, thread-like strands come out of the cut when you pull your finger slowly away, your plants have bacterial wilt. Spread by the feeding activity of cucumber beetles, there is no cure for this cucumber plant disease. Destroy the plant immediately to keep it from spreading to other cucumber vines.

While you may think that wiping out every cucumber beetle within three miles of your garden is the way to combat this pathogen, that isn’t the best solution, even if it was possible. Instead, focus on planting only bacterial wilt-resistant cucumber varieties in your garden in future years. You know what they say: An ounce of prevention is worth a pound of cucumbers! Some of my favorite bacterial wilt-resistant cucumber varieties are ‘County Fair’, ‘Salad Bush’, ‘Marketmore 76’, and ‘Saladin’. They’re all great tasting and very prolific, in addition to resisting wilt.

Bacterial wilt is among the most common cucumber plant problems for vegetable gardeners

Bacterial wilt will bring eventual death to plants. It’s best to remove the plants as soon as infection is confirmed.

Fusarium wilt on cucumbers

Another one of those cucumber plant problems that’s a challenge to diagnose and defeat is fusarium wilt. This pathogen tends to be far more common in warm, southern climates and can affect a broad diversity of vegetable plants in addition to cucumbers. Early signs include drooping leaf stems. Sometimes an entire branch might wilt, starting with the lower portion and progressing upwards. Slice open the main stem of a cucumber plant you suspect is infected with fusarium wilt. If it’s infected, there are dark streaks running lengthwise through the stem. Sometimes there are dark, sunken cankers at the base of the vine, too.

This pathogen lives in the soil for many years and spreads from plant to plant on water, equipment, or plant debris. Even humans can accidentally spread fusarium wilt. Sadly, there is no cure. Remove and destroy infected plants immediately.

Focus on preventing it next year by planting only resistant varieties with the disease-resistance code FW on their seed packet. Soil solarization can help kill the spores in the top few inches of soil. Rotate your cucumber crop to a new place each year. Biological fungicidal soil drenches and additives can help, too, including those based on the bacteria Streptomyces griseoviridis (brand name MycoStop®) or a granular one based on the fungus Trichoderma virens (brand name Soil Guard®).

Cucumber mosaic virus is a common cucumber problem

This deadly plant virus is spread from plant to plant on tools and hands. It also spreads through the feeding of sap-sucking aphids. Symptoms of cucumber mosaic virus most often appear as a mosaic-like pattern of light and dark green on the leaves (almost like a checkerboard). The growing points are malformed, and there are spots, warts, or line patterns on the fruits. Unfortunately, there is no cure for this plant virus. Prevention is key.

Only purchase cucumber varieties with a resistance to this virus. This is especially important if you’ve had trouble with this pathogen before. The disease resistance-code CMV will be on the seed packet or seed catalog description of resistant varieties. Good choices include ‘Boston Pickling Improved’, ‘Eureka’, ‘Little Leaf’, ‘Salad Bush’, ‘Straight Eight’, and ‘Marketmore 76’. Purchase new, certified virus-free seeds each season. Though “cucumber” is in the name of this pathogen, it affects a wide range of plants, including vegetables, flowers, and weeds. Destroy infected plants to prevent further spread.

Mosaic virus is a common cucumber plant problem. Mosaic virus leaves foliage mottled with yellow in a checkerboard-like pattern.

Cucumber mosaic virus causes a checkerboard-like variegation on the foliage.

Cucumber plant problems solved

It may seem daunting to identify and manage issues with your cucumber vines. But the truth is that you’ll have many more years of success than you’ll have troubles. With healthy soil, adequate water and nutrition, and proper care, healthy and productive cucumber vines are definitely in the cards. Enjoy the harvest!

Healthy vines mean a great harvest!

Plant a variety of cucumber cultivars in your garden to limit disease and other problems.

For more on managing garden diseases and pests, check out the following articles:

Zucchini problems and how to solve them
Common tomato diseases
Plant pathogens and organic controls
6 steps to grow a healthy tomato garden
Guide to vegetable pests with organic fixes

Have you faced cucumber plant problems in the past? Tell us your issues and solutions in the comment section below.

Not sure what's wrong with your cucumber plant? It might be one of these common issues.

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23 Responses to Identifying and solving cucumber plant problems

  1. Ken Lovell says:

    You’ve left out two of the most difficult challenges for Australian gardeners: cucumber fly and root knot nematodes. Only some varieties seem attractive to the former, so trial and error will help find the ones to grow. Unfortunately (despite numerous folk remedies online) there is no way to get rid of the latter. Once the soil has a heavy nematode presence, the only solution is growing in containers.

    I confess I’ve never found an effective remedy for powdery mildew once it’s established, but growing the plants on a trellis with lots of air movement has (touch wood) prevented it starting in recent years.

  2. Duane L Hawkinson says:

    Unfortunately, I’ve come across a chronic problem that typically reveals itself just as cucumbers are ripe, succulent, and moments from harvest: The first can be diagnosed by virtue of identifying small scratches and dental patterns in the flesh of the cucumber. The second can be identified by the absence of any fruit. Gone. Mysteriously. Usually after my neighbor Sanjay has stopped over for a beer and a tour of the garden. I ‘m still trying to match dental records to solve the first mystery, but the varmint won’t come down from the tree.

  3. Ingrid says:

    I simply cant grow them. Tried varieties, from seed anx from stock. Planted 6 varieties in ddifferentparts of the gargardePlanted on soil amendment.Fertilizer. rotated. Nothing work’s. They stunt and wilt.
    3 years in a roll.

    • Sounds like bacterial wilt may be the culprit. Try growing resistant varieties. Another possibility is a soil-related issue. I recommend having your soil tested by your local extension service.

  4. Dan Thompson says:

    All of my plants seem to just have male blossoms, no fruit emerging at all from behind the blossoms, what do I need to do next?
    I do not remember what variety I planted from seed, so def will keep track of that next season.
    Very few bees this year here in west Texas, so don’t know if pollination is the problem too.
    Any suggestions will help, thanks

    • The male flowers are always produced a few days to two weeks before any female blooms arrive. This is to ensure there’s ample pollen already clinging to pollinators when the female flowers open. Just be patient. The female flowers will arrive soon.

  5. Jo says:

    Do I need to worry about cucumber beetle larvae in the soil destroying the roots?

    • I have not had problems with them in my garden and I seldom hear from gardeners who have issues with the larvae. If you do find your cucumber plants are weak and have puny, chewed roots, beneficial nematodes can be applied to the soil in your vegetable garden to help manage the cucumber beetle larvae.

  6. Brandon says:

    Something is destroying the newly form leaves at the end of my persian cucumber plant. Older leaves are not harm. Whatever it is, it is not messing with my armenian cucumber plant. I hope you can figure it out.

    I’ve tried blocking the general path to the area where I grow them. Now I went as far as to put a fence around the persian cucumber plant. I am quite frustrated. I hope you can give me some pointers. Also I live in the North bay area in California.

  7. Sarah says:

    My female cucumber flowers keep having little cucumber buds and the flower Browns and then the tip of the bud browns and nothing happens. I have threee lemon cucumber plants on a trellis with a zillion male and female blooms but for 4 weeks no fruit. :/

    I had also had Golden sweet pea planted on this trellis and notes green aphids early June so I pulled them and have not noticed aphids since. I have seen a yellow spotted beetle bug though.

    What is wrong with my lemon cucumbers?

  8. Jorge says:

    I’ve successfully grown gherkins in a greenhouse for several years but this year there is a new problem. Fruits are forming in the usual number but each fruit, once formed, stops growing. None have swelled at all. The first fruits appeared over two weeks ago and by now I’d expect to be picking for cornichons and looking forward to larger ones. None are over 2cm long at most and are showing no signs of getting on with it. I’ve fed with standard tomato fertiliser 3 times over the past two weeks, too. Anyone any ideas?

    • Sounds like the flowers aren’t getting pollinated in your greenhouse. Could be you grew self-fertile/parthenocarpic varieties in the past which don’t need to be pollinated, but standard varieties do. Try hand pollinating in the morning with a paint brush and see if that helps.

  9. Casey says:

    I’ve been growing Armenian cucumbers this summer, the first month was great lots of cucumbers, second month still harvesting lots of cucumbers except they become extremely seedy and almost mushy..Doesn’t matter what size they are small or large they are mushy and most seed on the inside…What do you think happened? We did start getting extreme temperatures almost a hundred, could that be the problem? I was watering them every day but maybe it’s not enough

  10. KimW says:

    Greetings – My cucumbers have very few flowers. The vines aren’t especially vigorous or green, as the described symptom for too much nitrogen. I’ve only fertilized them with an organic 9-2-7 once, at initial planting. We’re in Northern Michigan. Cucs get 12-14 hours sun per day. We water everyday, like everyone else does “up here”. The one thing different about this year’s plantings is they were planted from seed at the end of May because my starters failed (it happens). Also, this year has been unusually warm with day temps in the low-mid 80s. Variety is Marketplace 76. Thoughts? Perhaps I just need to be more patient since they were started so late? Many advanced thanks!

    • Marketmore 76 requires about 65 days to reach maturity, so they should be producing by now, even if they were started a little late. Low to mid 80s isn’t too warm for cucumbers, so I don’t think that would be the issue. Perhaps a phosphorous deficiency in the soil is to blame. phosphorous promotes flowering and fruiting. I suggest having your soil tested to see if that could be the issue.

  11. Kathleen Tompkins says:

    I have beautiful cucumber plants that have taken over a large area and have big healthy looking leaves and is loaded with hundreds of flowers. I have so far gotten only 5 mature and delicious cucumbers. Why am I not getting more?

  12. Meredith A. says:

    I have a cucumber plant that is only growing small ball-like fruits. The vine started out looking normal but has now become very thick and is curing in on itself with clumps of many flowers. Is this something you are familiar with?

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