Sweet potatoes are the sweet and delicious distant relatives of regular potatoes that are low-maintenance vegetables often confused for yams with a unique sweet and starchy taste. To grow a supply of fresh sweet potatoes, learn when to plant sweet potatoes in your vegetable garden.
Although they are similar to potatoes, sweet potatoes are not directly related to potatoes as they are not part of the Solanaceae family. There is also a difference between yams and sweet potatoes. Because of this, sweet potatoes are a perfect substitute for anyone who can’t eat nightshade crops. Sweet potatoes belong to a genus of plants that includes morning glory flowers.
Sweet potato leaves that grow above the ground are edible when cooked like spinach. Sweet potatoes do not require specific growing conditions, but they enjoy growing in well-draining soil in full sun. To grow and harvest a healthy yield of sweet potatoes, plan when to sow seeds in the garden to make the most of the sweet potatoes growing season.
When to Plant Sweet Potato Slips
Sweet potatoes are tubers like beets, meaning the same vegetable we eat is a structure for the storage organs that hold nutrients. Sweet potatoes cooked in their skin are excellent sources of vitamins A and C and manganese. When we plant potatoes or slips, they sprout into a whole new plant.
When to Plant Sweet Potatoes (Ipomoea batatas)
Sweet potatoes are native to the tropical portions of the Americas, making them warm-season crops. If you’re wondering when to plant sweet potato slips, the best time is after the ground thaws in spring. As warm-season vegetables, sweet potatoes do not handle frost well, so wait for the last frost date in your area to pass to sow seeds in the garden.
Years of growing and cultivating sweet potatoes have seen the rise of many cultivars, including short-season varieties. These variations of sweet potatoes are perfect choices for home growers living in cooler growing zones. Shorter periods of growth allow anyone to make the most of their sweet potatoes growing season.
Because of how sweet potatoes grow, raised beds or creating mounds of loose soil is the best way to plant potato slips. Make these mounds at least a foot taller than the ground level and spaced at least one foot apart. Leave three feet of space between each row of mounds for harvesting and watering.
Don’t forget about amending your soil. The best homemade fertilizer for potatoes contains potash, kelp, bone meal and cottonseed meal. The potatoes love it.
When to Plant Sweet Potatoes in Zone 5 and Below
USDA Hardiness Zones 3 through 5 cover the northernmost part of the United States down to roughly the country’s middle. This area experiences cool weather for more than half of the year, defining the best time to plant sweet potatoes.
To successfully grow sweet potatoes, plant slips in soil with a temperature of at least 60°F. Depending on the location in this zone range, growing sweet potato plants can take place anytime from May to June.
Sweet potatoes reach maturity between 90 and 120 days. To avoid the stress of not harvesting in time before the first frost in fall kills your sweet potato vines, plant slips from fast-growing varieties in the home garden.
Slips are available for purchase at the start of the sweet potatoes growing season. Starting from slips shaves about a month of the time to reach harvest. These varieties grow quickly. When to dig sweet potatoes is when they reach maturity in about 80-90 days.
When to Plant Sweet Potatoes in Zone 6
Zone 6 shares elements of its climate with its neighboring zones, meaning that when looking for when to plant sweet potato plants or to plant yams, the answer is to wait until April or early May. To boost your soil temperature, lay sheets of black plastic during the day.
As the sunlight hits the plastic, it warms the ground. Once your soil is at the right temperature, cut holes in the plastic, and plant slips into your soil mounds. Add a ground cover to the garden bed to ensure your sweet potatoes don’t compete for nutrients with weeds and that your soil doesn’t dry out too fast.
Ground cover ranges from other plants with sprawling vines to cover the ground, or you can create a layer of organic matter mulch over your mounds after starting your new plants. An alternative to growing in mounds is to plant slips in containers or raised beds.
Five-gallon buckets make excellent containers for growing sweet potatoes. Place your container in a full sun location and fill the bottom six inches with potting soil and fertilizer. When growing sweet potatoes in pots, place up to four slips inside with equal spacing from one another.
Cover your slips with soil and water your sweet potatoes. After sprouting, when your sweet potatoes grow at least six inches, add more soil to cover all visible stems. This process of covering new plant growth is known as hilling, and you’ll repeat it throughout the growing season to encourage stems to produce more sweet potatoes.
Covering the stems of your sweet potatoes is also effective for preventing sweet potato weevils from laying eggs inside your plant. Weevils feed on parts of sweet potato plants during their life cycle.
When to Plant Sweet Potatoes in Zone 7 and Higher
Growing 7 seven starts just below the middle of the country and extends south to cover the parts of the United States with almost year-round warm weather. Start planting sweet potatoes in these warm regions as early as February in areas where the ground doesn’t freeze.
Gardeners in warm growing zones don’t have to worry about frost so they grow a variety of sweet potatoes without worrying about beating the growing season.
Covington sweet potatoes are medium-sized spuds that are one of the newer cultivars introduced. This variety has resistance to soil rot, nematodes, and fusarium wilt and reaches maturity in 120 days.
Jewel sweet potatoes are a variety of sweet potatoes loved for their copper skin and bright orange flesh. These sweet potatoes grow well in most of the country, thriving in zones 4 through 12. Jewel sweet potatoes reach maturity in roughly 130 days and don’t mind growing in partial shade.
Garnet sweet potatoes are among the most popular sweet potato types in the United States. Garnet sweet potatoes account for 90% of all sweet potatoes grown in the country. These sweet potatoes reach maturity in around 110 days.
What to Do During Sweet Potatoes Growing Season
If you want homegrown sweet potatoes but don’t want to purchase potatoes made specifically for seeding, grow sweet potatoes from store-bought spuds with a little assistance to remove inhibitors from the potatoes that prevent sprouting.
Cut your potatoes so that each section has at least two eyes; these are the small nodes where new sprouts appear. Leave these slices out to dry and callous over. Once dry, place your potato slices into a plastic bag with a 70% ethanol alcohol splash. Leave your potatoes to sit for 48 hours before rinsing and planting them.
An easy way to start growing sweet potatoes is to place your potato slips in water to start the sprouting process. Stick your sweet potato pieces with toothpicks and position them in a jar of water with half of the sweet potato submerged. Leave the jar on a windowsill in the sunlight and wait for sprouts to emerge from the slip.
Sweet potatoes are nutritious and versatile enough that a bountiful harvest stretches across many meals. Monitor the soil temperature in your garden, and by the end of summer, you could have impressive yields of sweet potatoes to bring to the dinner table.
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