Hydroponic Sweet Potatoes – How To Grow

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By Jeff Hale

There’s nothing as rewarding as being able to use your store-bought food as a seedling. This is particularly true of the sweet potato. Sweet, delicious, and easy to grow, it is a versatile plant. They also can be grown to be a great creeper and decorative plant when trained over a trellis.

Sweet potatoes are highly nutritious and are a great source of fiber, vitamins, and minerals. Benefits include promoting gut health, potential cancer-fighting properties, supporting healthy vision and brain function, as well as helping your immune system.

This leads us to why you’d want to grow sweet potatoes hydroponically. While we’d expect that regular potatoes and sweet potatoes would require the same growing techniques, they are not related.

So, let’s talk more about what sweet potatoes are.


What are Sweet Potatoes?

While sweet potatoes and potatoes are part of the Solanales order, that’s where the family ties end. The sweet potato (Ipomoea batatas) is a part of the bindweed or morning glory family. This means it will produce a lovely vine and flowers.

Also, while some may refer to sweet potatoes as “yams,” they are not a part of this species either, as yams are more related to grasses and lilies.

Sweet potatoes are native to the tropical regions of the Americas. They were domesticated around 5,000 years ago and in recent years, they’ve been identified by NASA as a must-have crop for their Controlled Ecological Life Support System (CELSS) Program, because one slip can produce between 3 – 9 potatoes.

The color varieties of sweet potatoes are varied, including orange, white, yellow, and even purple. Also, unlike the ordinary potato, this is not an actual tuber you’re eating but a tuberous root vegetable.

And also unlike ordinary potatoes, you can grow them from grocery store purchases. Well, technically you will be planting slips of sweet potatoes.

Let’s talk about the methods you can use to establish your sweet potato crop.

Growing Hydroponic Sweet Potatoes At Home

There are three methods to start growing sweet potatoes at home, they include:

From Slips

You can grow a sweet potato from its slips, which are rooted sprouts that grow from a mature sweet potato. These can occur naturally in a kitchen cabinet when the potato shoots off a green branch with leaves.

If these slips start to wilt a bit, you can place them into a glass of water on a windowsill. After a little time you will see more roots develop. Think of the avocado pit method with toothpicks soaking in water, and apply this method to your slip.

Also, before potting it into your hydroponic setup, you can grow the roots in a Rockwool cube.

Sweet potatoes have two separate ends: sprouting and rooting. You can identify them by the tiny roots showing.

From Chitted Potatoes

You can pick up a chitted sweet potato from a garden center or you can chit your own. Chitting is just when the stems have started growing. These warm moist environments will encourage the potato to start sprouting. Once these have sprouted, you can either leave all the shoots and get a harvest of many smaller sweet potatoes, or trim off all but the longest three shoots and get three large sweet potatoes.

Now you can plant these chitted potatoes into a moist mixture of vermiculite (worm poop), perlite, and sand, in a warm environment or separate growing medium.

From Organic Sweet Potatoes

You can simply purchase an organic sweet potato and place it into the ground. Ensure it is organic and hasn’t been treated with an anti-sprouting agent.

This will be as simple as placing the potato straight into the growing medium.

Now that we’ve covered the numerous methods, let’s talk about the ideal growing conditions for sweet potatoes.

Optimum Growing Conditions for Sweet Potatoes

As we’ve mentioned, this is a tropical plant and does not like the cold. If your hydroponic setup is outside, wait for the last of the winter frost to disappear, and the warmth of spring has finally arrived.

When setting up your hydroponic system, ensure that night temperatures do not drop below 55°F, and during the day your growing medium will need to stay at least around 65°F.

Sweet potatoes are also thirsty and hungry plants. You will want to provide these plants with loads of water and nutrients. While you might have sprouted your sweet potato in water, it will need well-draining growing medium as it can’t reach its full potential steeped in water.

This drainage can be achieved by layering your growing medium with coco coir, perlite, and LECA (Lightweight Expanded Clay Aggregate). The mixture of coco coir and perlite will allow for some moisture and nutrient retention, with the LECA retaining water but allowing the excess to drain through.

The layering and mixture of the growing medium also needs to be light but still balanced to provide weight. As with ordinary potatoes, this weight will determine the size of the tubed roots.

For the depth of the container, you need the sweet potatoes to be planted at least 9 inches deep with a maximum of 24 inches. Some research will state that you can get away with 18 inches. Your hydroponic setup will need to accommodate this depth with a large container.

Sweet potatoes also require full sun. If you are growing them indoors, you must invest in a full-spectrum grow light. While LED lights are generally the go-to grow light due to power usage, old-school bulbs will work well due to the heat.

You will want to expose the plants’ foliage to light for 12-16 hours a day, but you might be able to get away with as little as six hours. Sweet potatoes will lap up as much sunshine as they are given.

When planting out your crop, make sure that they are spaced at least four to six inches apart. This will allow the plant to reach its full potential.

Fertilizer for growing sweet potatoes should come from the substrate itself, with maybe a teaspoon of organic nutrients, like worm team. But if you are buying off the shelf, try to source something with a nutrient solution of around 1:2.4 N P K ratios.

Water pH should remain strictly neutral, between 5.5 and 6.0. Researchers who investigated growing sweet potatoes hydroponically made sure to change the water every two weeks.

This study about the production of hydroponic sweet potatoes used a nutrient film technique (NFT) to grow them. If you want to optimize the growing conditions even more, you need an electrical conductivity (EC) ranging between 1,100 to 1,200 microS cm-1.

Research into the best growing conditions for hydroponically grown sweet potatoes is ongoing, with NASA eager to achieve the best results. Hydroponics can lessen the chances of the potatoes picking up soil-based diseases and it is a versatile vegetable, making it very attractive for long term NASA missions.

Now that we know the basic conditions that sweet potatoes will love let’s talk about how you can start growing sweet potatoes hydroponically.

How To Grow Sweet Potatoes Hydroponically

With researchers scrambling for answers, you will be on the cutting edge of horticultural science. We’d suggest following the researchers by selecting an NFT method of hydroponics. Here’s our recommendation: Best NFT Hydroponic System

This means your potatoes’ roots will be able to constantly tap into the nutrient solution, but the spud itself will remain out of the water. If this isn’t done, the potato will start to rot.

As we covered when we talked about the methods of starting a sweet potato crop, you will want to sprout your slips in Rockwool. Once roots are visible, place them into the NFT bed. You will want to layer the growing medium to ensure the potatoes do not get waterlogged.

With an NFT system, you will run the submersible pump throughout the day and you need to monitor the water’s pH and nutrient levels often.

While you can change the solution every two weeks, this might be required sooner. You’ll know by testing regularly.

Lighting and heat control are vital for sweet potatoes, make sure your growing environment doesn’t get too cold, or that lighting is limited. Your potatoes will want heat and light.

If the roots aren’t developing as well as you’d like, adding in rooting hormone will assist.

And when it comes to harvest time, stop the system and remove the tubers when dry. Handle with care as scratches and nicks will encourage spoilage in the potato.

Once removed, make sure to place the potatoes in a sunny spot that is well-ventilated for up to 10 to 15 days to ensure that they are ready for long-term storage. This process is known as curing.

When the sweet potatoes are cured correctly, make sure to store them away in an area that is around 55°F and has a humidity of around 75% – 80%. If done correctly, you can keep your crop for months.

So Much More To The Hydroponic World Of Sweet Potatoes

As a vegetable crop, you can attempt to grow hydroponically, there is honestly so much to learn. Growing these spuds will be rewarding, whether you’re a novice or an expert.

If you are an expert hydroponic grower wanting to make real strides into the horticultural world, this could be it. Discovering the best method of growing sweet potatoes could not only ensure that your pantry is well stocked but that humans will be able to explore the stars.

All thanks to a vegetable that’s technically not a potato.