What Is A Tuber?

Natural Potatoes Tubers

If you are just getting into gardening, chances are that you’ll hear some confusing expressions among plant types, and tuber plants first come to mind. Although tubers and root vegetables are the main types, adding expressions like tuberous roots to the equation just makes things complicated.

So what is a tuber? Tubers are when a parent plant creates several “children” plants, such as potatoes. And if the potatoes are not harvested, the above-ground stem with flowers will start to die off and the underground stem will utilize that stored energy to survive. 

Difference Between Tubers And Root Vegetables

When we look at a carrot, for example, you can harvest only one carrot from one seed. Also, the vegetable itself is all underground with the greenery above ground. This makes it a classic root vegetable.

Root Vegetables

On the other hand, the most common type of tuber plants would be potatoes which from one single plant could provide you several potatoes to harvest. The potatoes live underground but the tuberous roots are all connected to one single “potato plant.”

So, if you don’t harvest all the potatoes in the fall, the plant can use stored energy from the tubers to grow new chutes in the spring. Another major difference between classic root veggies and tubers like potatoes is how you can grow them.

You can use chutes from a potato or a piece of potato to grow new ones. It’s due to those little “eyes” that you’ll sometimes see on a potato. You can cut off the part with the eyes and use it as a seed, so new potatoes will develop from it.

Still, you should know what you are doing at this point, since the eyes can sometimes be poisonous. So, it’s best to never try to eat potatoes that developed these small chutes, and rather use them for planting new ones.

Stem Tubers

To help you get to know the essence of tuber plants, there are a few different types we’ll discuss. First, we have stem tuber plants that are different from what’s called root tuber. Stem tubers form thickened underground stems, and are tuber plants in a true sense.

Potato Stem Tubers

Root tubers are often mistakenly placed in this category as well, but there are some clear traits that define genuine tubers or stem tuber plants:

  • Bulbous stems that grow underground
  • Shoots that connect underground tubers with the main stem
  • They grow near the surface of the soil
  • Leafy plants
  • Swollen sections of stem 

One clear way of differentiating between the two is to pay attention to the plant structure. Stem tubers are swollen sections of the stem, whereas root tubers are enlarged roots. Stem tubers only occur on the main stem, while root tubers can show up at any root section.

Stem tubers are also perennials, and they grow larger every year. On the other hand, root tubers produce new roots every season. So, the growing cycle can also indicate a difference between these two types of tubers. 

Modified Stems

Many plants have stem modifications where the stems evolve into storage organs like tubers or serve another purpose such as reproductive ones. So, tubers are in fact modified stems, and there are a few other types of those:

  • Stolons
  • Tubers
  • Rhizomes
  • Corms

Enlarged stolons are much different than tubers since they spread above the ground and away from the main plant. They seem like thin stem branches and their counterpart, rhizomes, grow underground just like tubers.

Rhizomes often resemble root systems, as they spread underground with the nodes that aid in raising shoots. Corms store nutrients just like tubers, but these are usually vertically oriented, and they don’t have a swollen base.

So, among the types of modified stems, true tubers are quite distinctive and easily recognizable. 

Root Tubers

Root crops or root tubers are specific types of tuber plants that serve different purposes when compared to stem tubers. Often referred to as tuberous roots, they seem like swollen roots due to their storage function.

However, stem tubers can store more starch than root tubers, and the next generation of root tubers develops from new roots every season. A perfect example of root tubers is carrots.

The tubers also serve all the functions of the roots, such as water absorption and storing nutrients. The enlarged area also serves to anchor the plant in the soil, and “tuber” sections can emerge throughout the entire root.

A tuberous root is also an underground stem and it’s easily recognizable when compared to other modified stem systems due to the enlarged swollen section. Root tubers can’t develop into new plants as stem tubers, and it’s the biggest difference between the two.

Vegetables That Are Tubers

Potato Tubers

Whether it comes to root tubers or stem tubers, there’s a variety of veggies we use for food every day that are essentially tubers. Here’s a list of the tuber veggies you’ll probably tend to grow the most as they could easily reach your dinner table:

  • Potatoes
  • Parsnips
  • Turnips
  • Yams

Potatoes

Most commonly associated as a tuber plant.

These are edible tubers as long as you know what you can and can’t eat, as believe it or not, most parts of the potato plant are actually poisonous!

Potato plants fall under the nightshade family of plants and as such any stems or flowers contain poison. So don’t eat anything other than the potato itself and DO NOT EAT the potato if it has started to turn green!

Potatoes are easy to grow, and therefore represent the most common type of edible tubers. You can use each potato that’s started to sprout to plant more potatoes, and it only takes cutting the pieces that contain the “eyes”.

These are the sprouting points that you’ll want to plant into the soil with the cut side down, so it can keep sprouting and spreading. 

Yams

Yams are perennial root tubers that are often mistaken for sweet potatoes, but these are not tubers nor yams. It’s a root tuber plant that belongs to a completely another botanical family of flowering vines, whereas potatoes belong to the group of nightshade tubers.

However, both grow underground, are tubers, and represent some of the most commonly-grown tuber plants. You can grow yams much like potato tubers – they also sprout from the existing yam.

New chutes can be placed in the soil and they will sprout to produce new edible parts.

Are Carrots Tubers?

Carrots are root vegetables, so they are different from stem tuber plants, just like sweet potatoes, beets, turnips, and parsnips. They have a chute at the top, which means they all flower.

Carrots Root Vegetables

You can grow carrots from seeds, and if you leave them over the winter, you’ll have new seeds in the next growing season. The main difference between growing stem tubers like potatoes and root plants like carrots is in the planting method.

While you can grow new potatoes from the cuts with “eyes”, carrots can only be grown from the seed. 

Final Thoughts

The word tuber has confused gardeners for years, so hopefully, you’ll now have a better understanding of the term. Growing them to get underground stems which could later help reproduce new plants without seeds is certainly one of their biggest benefits.

Still, root tubers shouldn’t be excluded as they are also common examples of tubers that you can easily grow in your yard.

Frequently Asked Questions (FAQ):

Is A Sweet Potato Considered A Tuber?

Sweet potatoes aren’t considered a true tuber species, but rather root vegetables. Even so, their swollen roots ultimately place them in the tuber category, although they are much different than the stem of regular potato plants.

What Is An Example Of A Tuber?

Potato is the most common example of a true tuber, along with radish, and cassava.

What Is The Difference Between A Bulb And A Tuber?

Both bulbs and tubers have evolved to ensure nutrient storage and support for the plant to survive in harsh conditions. However, tubers are modified stems and roots, while the bulbs are modified leaves, and that’s the core difference.

Can Flowers Be Tubers?

Yes, Dahlia is one such example, though the term is widely used it is not technically a tuber in the same way that a potato would be.

Recent Posts