In light of the recent $1 million potato photo sale, I thought I would share the amazing story of tubers.
Tubers are geophytes.
Geophytes are plant organs used to store food and water. They are also used in asexual reproduction. These plant organs can start out as either modified roots or stems, depending on the plant. Modified stems are called stolons. Stolons are stems that grow at or just below the soil surface as “runners”. These “stems” are converted into adventitious roots at the nodes and what would have been a bud above ground becomes a spud below. There are several types of geophytes: bulbs, corms, rhizomes, and everything else. That “everything else” is what we call tubers. Common tubers include dahlias, gloxinia, and the lowly spud.
The “eyes” seen on a potato are actually stem nodes. Within each potato, you will find the same plant cells you would find above ground: vascular bundles, pith (spongey tissue), and cortex (outer tissue). Now here’s the funny part. While our standard spud grows from stem tubers, sweet potatoes grow from root tubers. The internal cell structure is very different. Root tubers have no nodes. That is why sweet potatoes have a more elongated form. At one end, you will find crown meristem tissue, which grows into stems and leaves. At the other end, called the distal end, the tuber produces roots.
Growing potatoes is surprisingly easy and I urge you to give it a try. In his book, The Botany of Desire, Michael Pollan describes how many potato farmers will not feed what they’ve grown commercially to their families. This is because of all the fungicides, herbicides and pesticides that are applied to commercial crops. Mr. Pollan learned that they grow a separate crop for their family, using a significantly lower amount of chemicals.
Now, we’ve all heard about the Great Potato Famine of 1845-1852. Over 1 million people starved to death and another million abandoned Ireland, all because of potato blight. Potato blight is a fungal disease that causes the tuber to rot in the ground. This is why so many chemicals are commonly used when growing potatoes, but small-scale potato gardening can do without.
While potatoes can can certainly be grown from spuds bought at the grocery store, this is a bad idea. Foods bought in the store are safe for human consumption, but they are not guaranteed to be free from common garden pests and diseases. You don’t want to introduce Phyophthora infestans, the cause of potato blight, into the garden. You are far better off buying certified “seed potatoes”.
The easiest way to grow potatoes is in a barrel, large planter, or in a tower. If potatoes are planted in the ground, you will be finding rouge spuds for many years. Also, digging them up from the ground is, let’s face it, work. Growing potatoes in containers makes harvesting significantly easier and they make nice summer patio plants!
To begin, fill the bottom of the container(s) with 4" of loose, moistened soil. Cut seed potatoes into 2 inch chunks, making sure that each chuck has several eyes (small seed potatoes can be planted whole). Place the chunks 6" apart and cover them with 3" of moistened soil and repeat the process until the container is filled. Water lightly and be sure to place planters where they will get lots of sun. To build a tower (which works nicely for strawberries, too), simply take a section of chicken wire or hardware cloth and create a cylinder. Landscape cloth can also be used, but it may fall over. You can also grow potatoes indoors, near a window, if it gets enough light!
Potatoes need loose, well-drained soil and frequent, light watering. Never let potato plants sit in water, they will rot. Potatoes use a lot of nitrogen and potassium, and they prefer acidic soil (as low as 4.8 pH).
At first, it will look as though nothing is happening. As a gardener, you know the value of patience. With time, water and sunlight, tubers will send out roots and stems that will pull nutrients from the soil and create carbohydrates out of sunshine. (Don’t you just love photosynthesis?) Before long, the container will be filled with lush, green growth. Aside from occasion watering and feeding (aged compost works great!), that’s all you have to do until it completes the season’s life cycle.
Eventually, the lush above ground growth will start to die off. When it starts looking ragged, dump the contents of the container out on a tarp and remove the mature potatoes. Now comes the really cool part: mix the remaining soil, leaves, stems, roots, and immature spuds with some aged compost and do it all again ! Just cover it all up with soil and add water. I have been growing potatoes from the same batch of seed potatoes for six years! And, honestly, homegrown potatoes taste far better than store bought spuds.
You can grow a surprising amount of food in your own yard. Ask me how!