how to protect cucumber plants from heat

Every plant needs light to grow, and cucumbers are no exception. If you have a shady garden, it is natural to wonder how much sunlight your cucumber plants will need. So, do cucumbers like full sun? Cucumber plants like full sun and will grow best with lots of direct sunlight – 8 to 10hours per day is ideal. Cucumber plants can still bear fruit with less sunlight, but they will produce less. Cucumber plants can grow indoors without direct sunlight if you provide the right type of artificial light. Of course, you can have too much of a good thing. Intense direct sunlight during a dry spell will leave your cucumber plants dry and can slow down fruit production. In some cases, too much sunlight can even cause premature ripening of cucumber fruit! In this article, we’ll talk about how much direct sunlight cucumber plants need and ways to provide more. We’ll also talk about what happens when cucumber plants get too much sunlight and how to prevent this problem. Let’s shed some more light on this topic. Do Cucumbers Like Full Sun? According to the Texas A&M University Extension, cucumber plants like full sun. As such, they grow best when they get full sun for most of the day. Cucumber plants grow best with full sun (6 to 10 hours of sunlight per day). (By the way, cucumbers are native to India, and they belong to the same family as melons, squash, and pumpkins: Cucurbitaceae). How Many Hours Of Sunlight Do Cucumbers Need? This still leaves the question of how many hours of sunlight cucumbers need to get “full sun”. It also raises the question of how intense the sunlight should be. The University of Maryland Extension suggests that cucumber plants should get at least 6 hours of sunlight per day. However, 8 to 10 hours of sunlight per day is even better for cucumbers. The table below summarizes the length of sun exposure for cucumber plants and the likely outcomes. Hours OfSunlight Per DayOutcome & ActionLess Than 4Not enough sunlight. Find a new area to plant.4-5Plants will be small with less fruit.6-7This is the minimum for healthy plants.8-10This is the ideal sun for best results.More Than 10A plant that has lost leaves may suffer.This table summarizes the length of sun exposure for cucumber plants and the likely outcomes. The sunlight should be “full”, without any shade from trees, shrubs, or nearby plants in the garden. If your cucumber plants are shaded for a good portion of the day, then they might do better in another location. Do Cucumbers Like Morning Or Afternoon Sun? According to the University of Massachusetts Amherst, cucumbers do best with full sunlight throughout the day. So, don’t limit their light intake during the day if you can help it: give them both morning and afternoon sun. Cucumbers prefer full sun, but late morning or afternoon sun is the most intense. However, if you have to choose, opt for late morning or afternoon sun for cucumber. The sun is more intense during these hours than at any other time of day. In fact, according to the EPA, the sun’s rays are the strongest from 10am to 4pm. So, if lack of sunlight is a problem in your yard, put the cucumbers in a spot where they can get late morning or afternoon sun. The only possible exception is if you are worried about damaging the fruit on your cucumber plant due to thin leaves. Can Cucumbers Get Too Much Sun? Cucumbers can get too much sun in some situations. Here are the two basic cases: Cucumber Transplants – if you forget to harden off your cucumber plants when transplanting outside, the intense sunlight (and other outdoor factors) can damage them.Established Cucumber Plants – maybe your cucumber plant has thin leaves due to a disease or a pest problem. Either way, this can cause too much sun exposure for the fruit. In that case, the fruit may ripen prematurely. Cucumber Transplants If you plant your cucumber seeds directly in the soil outdoors, you won’t have to worry about hardening off your plants. However, if you start seeds indoors, you should harden off the transplants when you put them outside. A cucumber transplant may have trouble in intense sunlight if you don't harden it off first. Hardening off will help young plants to make the adjustment from indoor conditions to outdoor conditions. It really just means getting them used to outdoor conditions (temperature, sunlight, wind, water, etc.) gradually, instead of all at once. If a cucumber plant is started indoors and then exposed to too much intense sunlight all at once, its leaves may scorch. On the other hand, gradually exposing a plant to more sunlight each day will give it the chance to acclimate and adjust to the new environment. You can learn more about how to harden off seedlings (and why you should do it!) in my article here. Established Cucumber Plants Too much sun can also harm established cucumber plants, but in a different way. Instead of scorching the leaves, intense sunlight is more likely to damage the fruit on established cucumber plants. The leaves of cucumber plants protect the fruit from sunlight and prevent premature ripening. According to the Utah State University Extension, too much intense sunlight exposure can cause cucumbers to ripen prematurely. Instead of ripe full-size cucumbers, you may end up with tiny ripe cucumbers. Too much sun exposure can happen for a few different reasons: Diseases – some cucumber diseases destroy the leaves, including powdery mildew (caused by humid conditions) or bacterial wilt (from cucumber beetles).Insect Pests – some insects attack the leaves on cucumber plants, including aphids and cucumber beetles. You can learn about how to get rid of aphids in your garden in my article here.Animal Pests – if they get hungry enough, some animal pests will feed on the leaves of cucumber plants, including rabbits, voles, chipmunks, squirrels, woodchucks, and deer. However, if there is fruit available, some animals will often go for those first! How To Protect Cucumber Plants From Heat & Sun If you are worried about intense sunlight (for recent cucumber transplants or established plants that have lost leaves), don’t worry. There are ways to protect cucumber plants from heat and sun – the name of the game is to provide shade. Here are some ways to do just that: Rig Up A Shade Cloth “Umbrella” – drape a piece of shade cloth over a trellis or cage that is supporting your cucumber plant. This will block out some sunlight and reduce the temperature by up to 10 degrees Fahrenheit. The type of cloth you use will depend on how much shade you need to provide (20% to 90% shade is available – you can learn more about shade cloth in my article here).Build A Shade Structure – if you are handy, you can build an arbor or pergola to provide shade and heat relief for your cucumber plants. The structure itself can provide shade, but vining plants that grow up and over will add block even more sunlight. You can learn more about these structures in my article where I explain them in more detail.Prune Carefully - avoid over pruning your cucumber plants! It may make sense to remove low hanging leaves on a trellised cucumber plant to avoid disease from splashing soil in the rain. However, removing too many leaves higher up on the plant will expose the fruit to intense sunlight.Choose Disease Resistant Varieties – if your cucumber plants stay healthy, they will have more leaves and a stronger root system. More roots help them to find water during a drought, and more leaves shade them from intense sunlight. An arbor can provide some shade for cucumbers and other plants if the sun is too intense during the hottest part of the day. Can Cucumbers Grow In The Shade? Cucumber may be able to grow in partial shade, but they do not grow well in full shade. Cucumber plants need full sun to grow their best and produce a good crop. If you are just planning your garden now, try to give cucumbers a sunny spot if you can. Leave the shady spots to more shade-tolerant plants, such as lettuce or spinach. Plant cucumbers in a sunny spot, and cut away some tree branches if necessary. If sunny space is limited in your garden, try to create more by pruning back the branches of nearby trees. If that is not possible, consider planting cucumbers facing the sun (south facing in the Northern Hemisphere). Also, plant cucumbers facing the sun in front of taller plants (like tomatoes or green beans) that could block out their sunlight later in the season. What Else Do I Need To Know About Cucumbers? In addition to full sun, cucumbers also like warm temperatures. It is best to wait until the soil temperature has reached 70 degrees Fahrenheit (21 degrees Celsius) before planting cucumber seeds. You can also start cucumbers indoors (3 weeks before you intend to transplant) to get a head start on the season. This is useful if you have a short growing season. The ideal temperature for cucumber seed germination is 75 to 85 degrees Fahrenheit (24 to 29 degrees Celsius). You can learn how to keep seeds warm (indoors or outdoors) in my article here. The ideal temperature for cucumber seed germination is 75 to 85 degrees Fahrenheit (24 to 29 degrees Celsius). The Old Farmer’s Almanac suggests waiting until at least 2 weeks after the last frost date to plant seeds or transplant cucumbers outdoors. You can find the frost dates in your area on this page from the Old Farmer’s Almanac. You can learn more about the lowest temperatures cucumber plants can tolerate (and how to protect them from cold) in my article here. Conclusion Cucumber plants can still produce some fruit with some shade during the day, but they would need an artificial light source to grow indoors. Remember that you will always get a better harvest if your cucumber plants get full sun for at least 6 hours per day (ideally 8 to 10 hours per day). If your cucumber plants are producing flowers but no fruit, you can find out why (and how to fix it) here. You might also be interested to read my article on sunlight for tomato plants. I hope you found this article helpful. If so, please share it with someone who can use the information. If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here. Enjoy! ~Jonathon