Potatoes are nutritious and versatile, and they are a great crop to add to your garden. They can grow in cool weather and will even tolerate some frost, but potatoes do have specific needs in terms of sunlight.
So, can potatoes grow in shade? Potatoes can grow in partial shade. However, to produce more tubers with bigger size, potato plants need at least 6 hours of direct sunlight per day. Potatoes grown in partial or full shade might not produce any tubers – if they do, the tubers will be small.
Of course, not every part of the potato plant needs lots of light. In fact, the tubers will turn green and may become toxic if exposed to sunlight!
In this article, we’ll talk about sun and shade for potato plants and how it affects them. We’ll also talk about how to shade potato plants without stunting their growth so you can get lots of big potatoes this year.
Can Potatoes Grow In Shade?
Potato plants can grow in partial shade. However, they will grow best and produce more (and larger) tubers with some direct sunlight every day.
Too much shade will prevent proper growth of potato plants after their green growth (shoots) break the surface of the soil. But what happens before they emerge from the soil?
Do Potatoes Sprout In Light Or Dark?
Potatoes can sprout in light and also in the dark.
Potatoes can sprout in shade or even in complete darkness. In fact, this is their usual method of sprouting.
Last year, we grew potatoes in one part of the garden and missed some of the tubers during the fall harvest. In the spring (in early May), we were digging in that same spot and found those tubers starting to sprout.
The underground tubers had grown some white roots and were sending up green shoots to break the soil surface! We dug them up and transplanted them to another part of the garden to join this year’s potato plants.
If you are trying to encourage faster potato sprouting, leave them out in the light. According to the University of Maine, the ideal temperature to “green sprout” potatoes is 70 degrees Fahrenheit (21 degrees Celsius).
Lay out the potatoes in a layer (don’t stack them up!) An area with high humidity works better for sprouting potatoes.
No matter what, you should avoid freezing temperatures, which will kill the sprouts and force you to start over again!
Do Potatoes Need A Lot Of Sun?
Although potatoes will sprout in complete darkness, they do need to get enough sunlight to produce energy after they start growing. Once the sprouts break the soil surface, their leaves will need light for photosynthesis.
According to the University of Michigan Extension, potatoes do best in sunny locations. Potatoes are a little more shade tolerant than their tomato cousins, but they still require some sunlight.
Although potato plant leaves need light to grow, their tubers and roots do not need light. In fact, potato tubers will turn green and produce a toxic substance (solanine) when exposed to light.
For this reason, it is important to use hilling to protect potato tubers from sunlight. Hilling simply means piling up soil (or mulch) around the base of a potato plant as it grows.
Eventually, this hill of soil around a potato plant will be 8 inches or taller by the end of the season. In addition to protecting tubers from sunlight, this hill also keeps the roots and tubers cooler.
The ideal soil temperature for growing potato plants is 60 to 70 degrees Fahrenheit (16 to 21 degrees Celsius). If the soil is too warm, tubers will fail to form and the plant’s growth will be stunted.
Luckily, there are some ways to keep potato plants a little cooler. These methods help potatoes to keep producing tubers a little longer when the summer heat arrives.
One method is to take advantage of spacing to let potato plants protect each other from the sun and heat. The University of Illinois suggests planting potatoes 12 inches apart.
As the potato plants grow taller, their leaves will shade the soil around them. This close spacing will help to cool all of the soil in the potato bed.
Another way to keep potato roots cool is to put down a layer of straw as mulch around potato plants. Add a layer of straw 8 inches thick when the plants are 6 inches tall.
Straw (and other mulches) will also smother existing weeds and prevent the growth of new weeds. This reduces competition for light, water, and nutrients. It also means less work to maintain the potato bed.
Do Potatoes Grow Better In Sun Or Shade?
Potatoes grow best when their top leaves get sun while their roots and tubers get shade.
There are a few keys to ensuring that the top leaves of potato plants get enough light:
- Choose a sunny spot – before planting potatoes, choose a sunny spot in the yard. Ideally, it should get at least 6 hours of full sun each day. Pay attention to trees – a spot that looks fine in the winter or spring may be in full shade once the leaves appear on deciduous trees. If you already planted but your potato plants are still small, you might be able to transplant them (learn more in my article here).
- Pay attention to neighboring crops – make sure you don’t plant potatoes too close to other tall crops (such as tomatoes, corn, or pole beans). These neighbors will block out sunlight to potato plants, especially if they are growing between the potatoes and the sun.
- Leave the tops exposed – to ensure that the top potato leaves get enough sun, don’t cover them with soil when hilling. Leave the top part of the plant exposed so that the leaves can absorb sunlight.
If done wrong, hilling will prevent potato plants from growing by denying them sunlight. When done properly, hilling is the key to keeping potato roots and tubers cool.
Keep piling up soil around the base of potato plants during the growing season as they grow taller. You may need to do this a few times, and the hill may reach 8 inches or taller.
You can use many different materials for hilling potatoes, including:
- Mulch (such as straw or wood chips)
Now you know how much sun potato plants need to grow properly. You also know how to provide shade to the tubers without stunting the plant’s growth.
You might also want to check out my article on how to plant sprouted potatoes and my article on growing potatoes in winter.
I hope you found this article helpful. If so, please share it with someone who can use the information.