When to Start Planting Sweet Potatoes? Detailed Guide to Planting Methods and Precautions

Sweet potato is a very common food in our lives. Because it is a high-yield crop with a short growing period, it is very popular among growers. But do you already know when sweet potatoes should be planted and how to plant them? Come take a look with the editor!

When to Start Planting Sweet Potatoes

Mid-April is the suitable period for transplanting seedlings. At this time, the temperature in early spring has generally warmed up and become basically stable. The suitable time for transplanting is after the late frost ends, when the soil temperature at a depth of 10 cm reaches above 15°C, and transplanting can begin. In the previous winter or early that year, plow early to sun-bleach the soil, then when planting, form ridges and prepare the beds.

The transplanting time should not exceed April 20, otherwise the harvest time will be delayed, which will affect the transplanting season of the subsequent late rice crop. Under suitable conditions, the earlier the transplanting, the longer the growth period, the earlier the tubers form, the more tubers are produced, the longer the period of tuber root expansion, and the higher the yield and better the quality; if transplanting is too late, the growth period is shortened, the sweet potatoes are fewer and smaller, the yield is low, and the quality is poor. The suitable time for transplanting is after the late frost ends, when the soil temperature at a depth of 10 cm reaches above 15°C (around mid-April). With plastic film mulching, transplanting can be appropriately advanced, and transplanting can begin.

Sweet Potato Planting Methods and Precautions

1. Dig holes. Sweet potatoes need more space than other garden vegetables. Space each hole 30-60 cm apart. The depth is from 3 cm above the base of the plant to the tuber roots.

2. Planting. Place the sweet potato seedlings one by one into the holes dug in advance, and cover the stems with about 1.5 cm of soil. The leaf portion of the sweet potato will grow vines outward, while the roots will produce tubers 15-30 cm deep in the soil.

3. Cover with film. Protect your sweet potatoes in cold weather by covering them with film. This will also help stop weeds from growing and prevent sweet potato vines from overgrowing and stealing nutrients from the tubers.

4. Watering. When sweet potatoes are first planted, they need a lot of water. As time goes on, you should reduce watering them, until later watering only about once a week. Start by watering every day, then reduce the number of waterings week by week.

5. Wait for the tubers to grow. Sweet potatoes need a relatively long growth period and will not mature for harvest until early autumn. Continue watering weekly, weed, and let the plants grow healthily.

6. Harvest the sweet potatoes. About 120 days after planting, the sweet potatoes should have reached full maturity. If possible, delay harvesting the sweet potatoes as long as possible (before frost), because this will produce larger and better-tasting tubers.

7. Post-harvest handling of sweet potatoes. After harvesting sweet potatoes, be sure to carry out post-treatment. This step is very important. It can make the sweet potatoes more fragrant (when first dug up, they have no fragrance) and make the skin tougher. Place the sweet potatoes in a place with a temperature of 29-35°C and humidity of 80-90% for 5-10 days. After that, they can be cooked and eaten! You can place a heater and humidifier in a large wardrobe or small room to post-treat the harvested sweet potatoes.

8. Store your sweet potatoes. One of the benefits of these lovely tubers is that, if stored properly, they can stay fresh for many months and still taste very good. Store them in an open, dry place with a temperature of around 21°C (this means do not refrigerate!). Never store sweet potatoes in a plastic bag or sealed container.

Methods for Late-Stage Management of Sweet Potato Planting

1. Prevent white grubs before planting.

2. Weed immediately after transplanting. Check for and fill in missing plants 3-5 days after transplanting to ensure a full stand.

3. During the early growth stage, cultivate and hill up soil in time. Generally cultivate 2-3 times, and combine cultivation with hilling to support the ridges; selenium-enriched purple sweet potato is most afraid of waterlogging, so it must be drained in time. When drought is severe, if conditions allow, provide timely drought relief. After the rows close, pull out large weeds.

4. Do not turn the vines; protect the stems and leaves, and lift the vines. When sweet potato vines are turned, because the stems and leaves are damaged, fewer nutrients are produced. At the same time, turning the vines also causes the leaves to flip and overlap and become crowded, damaging the vine tips and prompting axillary buds to produce new branches and small leaves, reducing photosynthetic efficiency, generally reducing yield by 10%-20%. To protect sweet potato stems and leaves and promote tuber root expansion, apart from early cultivation and weeding, turning the vines is generally not needed. Entering the rainy season, adventitious roots easily form on the sweet potato vines, dispersing nutrients, so the vines should be gently lifted and then put back in place, to inhibit the growth of adventitious roots on the vines and concentrate nutrients in the tubers. When lifting the vines, prevent breaking or stepping on and injuring the sweet potato vines.

5. Timely control aphids, sweet potato leaf rollers, tobacco cutworms, scarab beetles, and other pests.

6. Promote tuber expansion. By mid-to-late September, the temperature begins to drop, and the root system's absorption capacity is poor. At this time, sweet potatoes have the greatest demand for potassium fertilizer. The main method of potassium supplementation is foliar spraying, applying 75 kg of 0.3% potassium dihydrogen phosphate aqueous solution per mu or 150 kg of 7% plant ash extract.

7. Disastrous weather may occur in September and October, so do a good job of preventing waterlogging and drought. Purple sweet potato prefers a warm climate environment. The suitable growth temperature for stems and leaves is 18-25°C, and growth stops when the temperature is below 15°C. The most suitable soil temperature for tuber root growth is 22-24°C, and expansion stops when the soil temperature is below 20°C. Purple sweet potato is a short-day crop and needs sufficient light and high intensity. During the growth period of purple sweet potato, the suitable soil moisture is 60%-80% of the maximum field water-holding capacity.

Sweet Potato Storage Methods

There are two storage methods for sweet potatoes, namely the high-temperature storage method and the low-temperature storage method.

1. The high-temperature storage method is to heat the sweet potatoes after they enter the pit to 35-38°C and maintain this for 2-3 days, killing pathogens such as black spot disease and soft rot. Then lower the temperature to 10-14°C for low-temperature storage. This method works very well, but the cost is relatively high and operation is rather troublesome. Therefore, for farmers storing separately by household, the low-temperature storage method with chemical treatment is more suitable.

2. Low-temperature storage method. First, disinfect the sweet potato pit one week before the sweet potatoes enter the pit. A 1000-fold solution of 70% thiophanate-methyl, or an 800-fold solution of 50% carbendazim, can be used to spray and disinfect the inside of the pit. After the sweet potatoes are harvested, handle them promptly and put them into the pit promptly. A 1000-fold solution of 70% thiophanate-methyl, or an 800-fold solution of 50% carbendazim, can be used at a 1:1 ratio to soak the sweet potatoes, then remove them, let them drip dry, and put them into the pit. Third, after the sweet potatoes enter the pit, use various methods to keep the temperature inside the pit below 15°C and above 10°C. A pit temperature below 15°C can inhibit the activity of pathogens, and above 10°C can avoid freezing damage, achieving the purpose of safe storage.

So the best planting period for sweet potatoes is mid-April. Even though a sweet potato is small, growing it also requires a lot of effort! The editor has explained in this article some precautions for planting sweet potatoes, hoping it can be helpful to everyone.