Growing Watermelons
Sweet, juicy homegrown watermelons capture the magic of summer with
explosive taste that puts store-bought melons to shame. Like their cantaloupe
cousins, watermelons demand 2 to 3 months of heat to produce ripe fruit, which
makes growing watermelons in northern regions challenging, but not impossible.
By using plastic mulch to warm soil and floating row covers to trap warm air
near plants, gardeners in any part of the country can experience the homegrown
goodness of watermelons.Nutritionists have found that watermelon should be in most people’s diets because of all the health-promoting vitamin C and antioxidants—including beta-carotene and lycopene—in every bite. These fruits combine great taste with excellent nutrition, with no cholesterol and nearly no fat—in other words, the perfect dessert.
Soil, Planting, and Care
Growing watermelons requires warm soil. Don’t tuck plants into the garden until soil temperature is above 70 degrees F, which typically occurs about the time peonies bloom in northern zones. To be safe, wait until at least 2 weeks past your area’s last frost date. Prior to planting, cover soil with black plastic to hasten soil warming. Because watermelons are heavy feeders, prepare your planting bed by adding seaweed, compost, or rotted manure. For best nutrient uptake, the soil pH should be between 6 and 6.8, although the plants will tolerate a pH as low as 5. If you live near a horse farm, another option that works well is to excavate the soil 1 foot deep, add a 9-inch-thick layer of fresh manure, and then cover that with 3 inches of soil mixed with compost. This creates a bed with a high-nitrogen soil base that’s naturally warm. Some gardeners even plant melons in their compost piles to ensure a warm footing and adequate nitrogen.Give watermelon vines plenty of room to roam, which usually means spacing plants 3 to 5 feet apart. After planting, cover seedlings with floating row covers to keep out insects and trap warm air near plants.
Watermelon vines bear male and female flowers. Don’t be alarmed when some of the male flowers, which appear first, fall off shortly after they open; they are followed by female blossoms about a week later. The female flowers, which have a small swelling at the base of the flower, stay on the vine to bear fruit. When vines start to bear both male and female flowers, remove row covers.
Tackle weeds before vines start to run because it will be difficult to move among vines at a later stage without crushing them. Mulching soil under the vines helps suppress weeds and slows moisture evaporation.
Water plays an important role in keeping vines healthy and producing delicious fruit. Vines are most sensitive to drought during the time from planting to when fruits start to form. Avoid overhead watering. Soaker hoses or drip irrigation deliver water directly to soil, helping prevent possible spread of fungal diseases among wet foliage. Keep soil consistently moist, but not waterlogged, which will kill plants. It’s typical for leaves to wilt under midday sun, but they shouldn’t remain wilted into evening. Water vines early in the morning so leaves can dry before sunset, which will further help prevent fungal diseases.
Keep ripening watermelon from direct contact with soil to prevent rot and protect fruit from pests and rodents. When fruit is about the size of a softball, place it on a bed of straw or cardboard. Setting fruit on a light-reflecting surface, such as aluminum foil, will concentrate heat and speed up ripening. If large critters, such as groundhogs, discover your melons, protect ripening fruits by covering them with laundry baskets weighted down with a few bricks.
Some gardeners like to switch fertilizer during the course of the growing season. To do this, use a fertilizer with more nitrogen than phosphorus and potassium during the period between planting and when the first flowers open. Once flowering begins, use a fertilizer with less nitrogen and more phosphorus and potassium, such as African violet food or liquid seaweed.
Some believe that pinching off a vine’s growing shoots as watermelons start to ripen will cause the plant to divert all its energies to fruit ripening. Recent research has shown this to be false. It’s a vine’s leaves that produce the sugars that sweeten fruit, so anything that reduces the total number of leaves available for sugar production actually lessens the sweetness of the melon.
In colder regions, remove any blossoms that start to develop within 50 days of your area’s first average frost date. This will help ensure that remaining, larger fruits will ripen before frost.
Troubleshooting
Watermelons are in the same plant family as squash and cucumbers, but they do not cross-pollinate successfully. Your garden will depend on bees to pollinate the flowers, so cool, cloudy weather in the spring will slow down their development, as bees are less active in such conditions. Be patient until the weather warms.Fungal diseases can multiple rapidly on melon leaves. Alternaria leaf spot, anthracnose, and gummy stem blight produce spots on leaves, while stem blight also forms bleached or tan sections on stems and rot on fruit. Downy mildew causes yellow or pale green leaf spots, while powdery mildew produces white spots on leaves. Treat fungal diseases with fungicides. Check with your local garden center or Extension Service to learn which fungicides are approved in your state for the disease you’re fighting.
Also be on the lookout for pests. Melon aphids, for example, can quickly colonize a vine, so inspect leaf undersides daily. If you spot aphids, treat them with insecticidal soap. Spotted and striped cucumber beetles can attack vines, transmitting bacterial wilt disease, which causes vines to collapse without chance of recovery. Treat adult beetles with rotenone or a pyrethrum-based insecticide; apply at dusk to avoid harming honey bees.
Harvest and Storage
Watermelons typically ripen over two weeks. As soon as one melon is ripe, the others won’t be far behind. About a week before a melon is ripe, water only as necessary to keep vines from wilting. Withholding water causes sugars to concentrate in the fruit. Too much water reduces sweetness.You can judge a watermelon’s ripeness by its skin color. The rind changes from a bright to a dull green, and the part that touches the soil shifts from greenish white or straw yellow to rich, creamy yellow. Gardeners also judge a watermelon’s ripeness by rapping on the skin and listening for a low-pitched thud. Tune your ear to the incorrect sound by rapping on a few fruits that aren’t ripe. Underripe fruits resonate with a high-pitched, tinny sound.Watermelons will keep 2 to 3 weeks unrefrigerated. Place them in a cool basement to increase their holding time. After cutting, refrigerate unused portions. If you have extra melon on hand, dice or cut the flesh into balls and freeze for slushies.
Growing Cucumbers
A tropical vegetable, cucumbers thrive when the weather is hot and water is
plentiful. Growing cucumbers is for warmer weather: Plants are so frost-tender
that they shouldn’t be set into the garden until soil temperatures are reliably
in the 70-degree range (no less than 2 weeks after the last frost date).Cucumber plants grow in two forms: vining and bush. Vines scramble along the ground or clamber up trellises, while bush types, such as Burpless Bush Hybrid, form a more compact plant. Generally, vining cucumbers yield more fruit throughout the growing season. Bush selections are especially suited to containers and small gardens. You can increase the season’s yield of bush varieties by planting several crops in succession 2 weeks apart.
Whether you want a cucumber for slicing or pickling, there’s a variety to suit your taste. Lemon cucumber offers smaller fruits perfect for a single serving, while Boston Pickling boasts classic heirloom taste. The long Armenian cucumber is a specialty ethnic cucumber prized for taste and the fact that a single cucumber yields so many slices.
Soil, Planting, and Care
Cucumbers need warm, fertile soil with a pH of 6.0 to 6.8, although they will tolerate a bit more alkaline soil to 7.6. Work compost or composted manure into soil. Plant seedlings 36 to 60 inches apart, depending on variety (check the stick tag). For vines trained on a trellis, space plants 1 foot apart.In areas where spring is long and cool, you can warm the soil 3 to 4 degrees by covering the hill or row with black plastic.If you do not plant in black plastic, then mulch with pine straw, wheat straw, chopped leaves, or your favorite organic mulch shortly after planting. If the weather is unseasonably cool, you can wait a while to mulch until the ground is warmed by the sun. Mulch is especially important to keep the fruit clean for bush types and vines not growing on a trellis. Straw mulch is also thought to be uncomfortable for slugs and creates an uneasy footing for cucumber beetles, helping to keep them at bay.
If you can, trellis your vines. This keeps the fruit clean and saves space. A 12- to 18-inch diameter cage made from 4- or 5-foot welded wire fencing or hog wire will support 2 or 3 vines. Wire is easy for the tendrils of climbing cucumbers to grab as the plant grows.
Cucumbers grow fast and don’t demand a lot of care. Just keep the soil consistently moist with an inch of water per week (more if temperatures sizzle and rain is scarce). Inadequate or inconsistent moisture causes oddly shaped or poor-tasting fruit. If possible, water your cucumbers with a soaker hose or drip irrigation to keep the foliage dry. This helps prevent leaf diseases that can ruin the plant.
You can fertilize with a liquid food, such as Bonnie Herb & Vegetable Plant Food, every 2 weeks, applying it directly to soil around plant stems. Or you can use a granular, slow-release fertilizer worked into the soil when you plant or sprinkled around the plants later.
If vines bloom but don’t fruit, something is probably interfering with pollination. First, make sure that you see both male and female blooms. Male blooms usually appear first and then drop off, so don’t be alarmed if this happens. Within a week or two, female flowers will also appear; each one has a small cucumber-shaped swelling at the base that will become a cucumber.
Several pests bother cucumbers. Squash bugs may attack seedlings. Slugs like ripening fruit. Aphids can colonize leaves and buds. Straw mulch helps keep slugs at bay, as can trellising vines to get the fruit off the ground. Vines are also bothered by cucumber beetles, which chew holes in leaves and flowers and scar stems and fruits, but worse than that, they spread a disease that causes the plants to wilt and die. Powdery mildew is a disease that leaves white, mildew-like patches on the leaves. Apply fungicides at the first sign of its presence. To minimize disease spread, avoid harvesting or handling vines when leaves are wet.
Harvest and Storage
You can pick cucumbers whenever they’re big enough to use. Check vines daily as the fruit starts to appear because they enlarge quickly. Vines produce more fruit the more you harvest. To remove the fruit, use a knife or clippers, cutting the stem above the fruit. Pulling them may damage the vine. Don’t let the cucumbers get oversized or they will be bitter, and will also keep the vine from producing more. Yellowing at the bottom (blossom end) of a cucumber signals overripeness; remove the fruit immediately. Harvest lemon cucumbers just before they begin turning yellow. Although they are called lemon cucumber because the little oblong or round fruits turn yellow and look like a lemon, by the time the fruit turns yellow it may be a little too seedy for most tastes.You can keep harvested cucumbers in the refrigerator for 7 to 10 days, but use them as soon as possible after picking for best flavor. If you don’t eat a slicing cucumber all at once, cover the unused portion in plastic wrap to prevent dehydration in the refrigerator. In fact, it’s a good idea to wrap your whole cucumbers in plastic or store them in a zipper bag in the fridge to keep them crisp.
