By Dr. Mercola
Cucumbers are one of my most highly recommended vegetables, and if you have a garden, you can easily grow them at home.1,2, 3 Aside from being able to control pesticide and fertilizer use, you’ll also avoid the wax applied to many commercially sold cucumbers. There are dozens of varieties that thrive in both cool and warm climates, although they can be a challenge to grow if temperatures are consistently in the mid-90s.
While made up of 90 to 95 percent water, cucumbers still manage to provide a host of valuable nutrients, including vitamins A, B5, C and K, along with manganese, potassium, magnesium, molybdenum, copper, silica and fiber. Cucumbers also contain lignans that bind with estrogen-related bacteria in the digestive tract, contributing to a reduced risk of several cancers, including breast, uterus, ovarian and prostate cancer.4
Other phytonutrients called cucurbitacins — part of a larger group known as triterpenes, and the part of the cucumber that gives it a bitter taste — also inhibit cancer cell development. Preliminary findings also suggest cucumbers have antioxidant and anti-inflammatory properties.5
In traditional medicine, cucumbers are used to treat headaches. The seeds are diuretic, and the juice — thanks to caffeic acid and vitamin C — can be used as an acne treatment and a soothing remedy for tired, puffy eyes.
Technically, cucumbers are a fruit, related to both the melon and squash families. The three main categories of cucumbers you can choose from are:
- Slicing cucumbers: thick-skinned and generally larger, growing to be 6 to 8 inches long
- Pickling cucumbers: thin-skinned and smaller, reaching 3 to 4 inches in length
- English or gourmet cucumber, also known as "burpless:" a longer, thinner version with very small seeds
Some varieties of cucumbers will be more bitter than others. Beit Alpha, Lemon Cuke, Tendergreen burpless and White Wonder are among the sweetest. You can find a listing of other popular varieties on Rodale Organic Life’s website.6 As a general rule, cucumbers need quite a bit of garden space, as they grow on trailing vines. However, there are also bushy varieties that only need minor staking, making them suitable for container gardens.
Popular bush varieties include Hybrid, Salad, Picklebush and Arkansas Little Leaf, the latter of which will produce fruit without pollination, making it an ideal choice for apartment dwellers and small container gardens. To optimize your container-grown cucumber, plant it in equal parts of potting soil, compost, perlite and peat moss, and use a container that is at least 12 inches in diameter and 8 inches deep.
The plants also need five to nine hours of full sun. The greater the sun exposure, the more productive the plant will be. An east-west directed trellis will optimize light exposure. That said, if temperatures are consistently in the mid-90s, provide the plants with filtered afternoon shade to avoid overheating.
Planting and Growing Guidelines
Depending on the variety, your cucumbers will be ready for harvest in 50 to 105 days. For earlier harvest, start the plants indoors, using a grow light, approximately four weeks before your last spring frost date. They’re fast growers, though, so most gardeners will simply plant from seed directly in the garden.
For a late summer/early fall harvest, sow a second batch four to five weeks after the first. Cucumber plants are highly vulnerable to frost, so avoid planting seeds or seedlings in your garden until all danger of frost have passed, and the average soil temperature is at least 50 degrees F.
1. Plant seeds7 in rows, about 1/2 inch to 1 inch deep, anywhere from 1 to 6 inches apart. The plant will grow best in loose, well-draining soil. Mix in ample amounts of compost to encourage growth. Ideal pH is between 6 and 7.
2. Ideally, water heavily in the morning and allow it to lightly dry out to a depth of about 3 inches before soaking it again. This will help prevent stem rot and powdery mildew, as the plant has a shallow root system.
Allowing the plant to dry out too much can make the fruit bitter, however. A layer of mulch will help maintain the moisture balance. Adequate moisture is particularly important during flowering and fruiting. Sandier soils will require more frequent watering.
3. Once the plants are about 4 inches tall, thin the rows so the plants are spaced about 12 to 24 inches apart, depending on the variety.
4. Four weeks after planting, side-dress with compost, aged manure or 1 tablespoon of 10-7-7 organic fertilizer. A 7-5-5 or 6-3-3 balance can also be used, just make sure it has a slightly higher nitrogen ratio to stimulate leaf growth and fruiting. That said, excessive nitrogen (and/or low boron or inadequate pollination) will result in cucumbers with hollow centers — a sign of excessively rapid growth, preventing the fruit from forming properly.
5. As the plant grows, train it upward on your trellis. Alternatively, grow them in a large pot, whiskey barrel or raised bed, where it can sprawl over the sides. Growing them vertically will produce straighter fruit, however, and protect the fruit from pests and rot.
Pest Control and Pollination
The striped cucumber beetle, easily identified by its bright yellow body with black spots (resembling an elongated yellow lady bug), can be quite destructive, munching through the plant and spreading plant diseases such as mosaic virus and bacterial wilt, the latter of which causes the plant to wilt and die.
Wilt-infected plants will not produce fruit. Moreover, cucumber beetles are particularly attracted to plants with bacterial wilt, so be sure to remove any infected plants to prevent spread. To determine whether your plant actually has bacterial wilt, Gardening Know How offers the following suggestion:8
“[C]ut the stem and squeeze both ends. A sticky sap will ooze out of the cut. If you stick these ends back together and then pull them apart again, making a rope like connection between the two in the ooze, this means they have the bacteria. Unfortunately, once cucumbers have wilt there is no saving them.”
One of the most effective ways to control the cucumber beetle is to disrupt its lifecycle by covering young plants with row covers and rotating your crop each season. Keep the row covers on until the plant starts to flower. At that point, you want beneficial pollinators to have access to the plant.
Misshapen fruit is often the result of inadequate pollination. Flowering plants such as lavender, thyme and dandelion will attract pollinators such as bees and butterflies into your garden. If you notice a lack of pollinators, you may need to hand pollinate your cucumbers to ensure a successful crop. For instructions, see Gardening Know How’s “How to Pollinate Cucumber” section.9
A natural insecticide that can be used to ward off the cucumber beetle is kaolin clay. It needs to be applied preventatively, as it acts as a repellent. Common plant diseases include alternaria leaf blight, angular leaf spot and bacterial leaf spot — all of which can be reduced or prevented by selecting a disease-resistant variety.
Stem rot and powdery mildew can be prevented by following the watering schedule suggested in the top bullet above. Blossom end rot is discouraged by avoiding excessive drying of the soil between watering.
Harvesting and Storage
The cucumbers are ready for harvest when they’re about 1 to 1.5 inches in diameter, firm with round edges and a bright medium to dark green. Yellow, puffy, wrinkled or mushy water-logged fruits should be discarded. Yellowing fruit is a sign of over ripeness, the color resulting from a drop in chlorophyll — the exception being if you’re growing a yellow-fleshed cultivar, such as the Lemon cucumber.
The more frequently you pick the fruit, the more productive the plant will be, so harvest a few every couple of days. Harvesting in the morning will ensure maximum crispness. If you prefer less seedy cucumbers, pick them while they’re on the skinnier side. The seeds will develop the longer the fruit remains on the vine. With size, the cucumber will also develop bitterness.
To maintain their freshness longer, store your cucumbers at room temperature. Avoid overly warm areas, however, as vitamin C, B6 and carotenoids are susceptible to heat damage. Loss of these nutrients may be slowed through refrigeration.10
Half-used cucumbers can be refrigerated in a sealed container to prevent them from drying out. Avoid storing cucumbers near bananas, melons and tomatoes, as these produce ethylene, a plant hormone that initiates the ripening process. For optimal quality, use up fresh cucumbers within two days.
Ways to Use Cucumbers
Fresh cucumbers are delicious sliced with a pinch of salt, or pickled with some vinegar and sliced onions. Pureed cucumbers also make for a refreshing, cold gazpacho soup.
Simply mix the cucumber puree with fresh diced tomatoes, green peppers and onions; salt and pepper to taste. Diced cucumbers can also be added to tuna fish or chicken salad. Other simple cucumber recipes include cucumber salad with lemon herb dressing and feta and cucumber rolls with creamy avocado.
There are many ways to use cucumbers that do not involve eating them, however. Mother Nature Network’s article, “13 Ways to Use Cucumbers” offers a range of tips, including the following:11
- Hair conditioner to counteract chlorine damage: Blend one egg, 1 tablespoon of olive oil and one-quarter of a peeled cucumber in a blender. Spread the mix evenly through your hair and leave on for 10 minutes. Rinse thoroughly
- Refreshing skin tonic: Puree one whole cucumber in a blender with 4 tablespoons of fresh mint and pour through a strainer. The juice toner can be stored in the fridge for 24 hours. Cucumbers have near-identical pH as skin, making it excellent for skin health
- Anti-blemish face mask: Blend a 1-inch slice of peeled cucumber in a blender until liquid, then add one drop of rosemary essential oil. Whisk one egg white until stiff, then fold in the cucumber liquid. Apply to face, avoiding your eyes and mouth. Leave on for 15 minutes, then rinse off with a damp washcloth
- Cooling summer bath: Add 2 cups of Epsom salt, one sliced cucumber and a handful of crushed peppermint leaves (to release the oils) to a tub of tepid water