Whether you intend on planting potatoes in a garden trench, in containers, or even in your unused parking lot stall at work, your key to success is an understanding of how potato plants grow. The little spud that you plant (called a seed potato) is a tuber – part of the plant’s roots in which it stores energy for growth the following year. If you’ve ever left a potato out on your kitchen counter, you’ll know what eventually happens… The “eyes” of each potato sprout little growths called stolons. When these sprout below the soil, they grow vertically upward, and once they reach the surface they become the stem and leafy upper portion of the plant.
New tubers (more new potatoes) form along the length of each stolon, and at first they’re just tiny little bumps. As the above ground leaves of the plant take in energy from the sun, and the roots take up moisture and minerals, each new tuber begins to swell, beginning the energy storage process again to get the mature plant through winter. The greater the length of the stolon in the soil, the more tubers form along its length. The potato grower needs to maximize the amount of contact between the stolons and the soil, and there are a few different ways to make this happen.
The traditional farming method of planting potatoes is to dig a series of trenches about 6” deep. The seed potatoes are placed about 12” apart, very evenly down each trench. The tractor makes a second pass, and covers the potatoes with 3-4” of soil. Once the plants have emerged and are growing vigorously, the tractor makes another trip down the rows, hilling soil up, and covering the bottom of each plant with more soil. Unlike most other types of plants, piling soil up so that it covers the lower stem and lower leaves will not kill potatoes. It just encourages more root growth.
If you were planting in a container like the Potato Bag, you would add a shovel-full of soil to the bottom, lay down five or six seed potatoes, and then add about 6” of soil to cover them up. Once the plants are growing well, and have reached 12” above the soil surface, you would add a further 6” of soil, so that the plants are buried waist-deep. You can repeat this until the soil is level with the top of the potato bag. This creates a large vertical space in which more tubers can grow. Garbage cans also work well.
This principle is always the same. If you were to place a seed potato right on the bare ground and cover it with a 6” high pile of soil, it will sprout just fine. Keep adding soil (“hilling up” as it is known), and it will produce more potatoes for you. One of our customers described planting potatoes in his parking stall at the church where he volunteers. He laid down a couple of layers of cardboard from collapsed boxes, and then laid his seed potatoes on top. Over this he laid 12” of straw. Once the plants were a foot high, 6” more straw was added, and he repeated this process all spring, ending up with a pile of straw about 4 feet tall. Kept well watered, straw is just as good as soil for growing potatoes. At harvest time, the straw was just removed and used as mulch in his other garden, and it had already begun to break down. All of the potatoes were easy to find and harvest as the straw was removed.
Typically, you can count on harvesting ten times more potatoes by weight than you plant. Plant 1 kg of seed potatoes, and you should be able to harvest at least 10kg. With some conscientious hilling up, and in nicely fertile soil, you can expect as much as 15 times the weight planted. Consider using straw as your hilling up material, because it will keep the soil cooler and moister as the plants develop, and it makes a great addition to the compost heap at the end of the season.
Aside from hilling up, here are our top five tips for tip top potatoes:
1. Plant potatoes in full sun, and avoid freshly limed beds. Potatoes like slightly acid soil with a pH of 6.0 – 6.8. Organic matter in the soil will improve your crop, but use well rotted compost or dig in a cover crop the previous fall. Avoid fresh manure.
2. Once you plant your potatoes, don’t water them until after you see the plants sprout above ground. This will help to prevent soil diseases from affecting your crop. Once they’re growing, keep your potato plot evenly moist, particularly once the plants begin to bloom.
3. For fresh baby or “new” potatoes, wait until the plants are in bloom. That’s usually a good indication that an early summer harvest is ready.
4. For storage potatoes, wait until the plants wither and turn brown, and then leave them in the soil for a further 3 weeks as their skins firm up. Harvest them for storage if there’s a threat of very cold or very wet weather.
5. Store potatoes in a cold, dark place, above freezing, with good ventilation. You can brush soil off your harvested spuds, but don’t wash them – the extra moisture is not good for storage. Check your stored potatoes frequently throughout winter, and remove any that are turning soft or looking mouldy.
More on how to grow potatoes here.
As a seasoned horticulturist and gardening enthusiast with years of hands-on experience, I've delved deep into the intricacies of cultivating various crops, and potatoes are no exception. My expertise extends from understanding the botanical mechanisms behind plant growth to implementing practical cultivation methods that yield optimal results.
In the realm of potato cultivation, it's crucial to grasp the life cycle of the potato plant. The key player here is the seed potato, a tuber that serves as the energy storehouse for the plant's subsequent growth. Observing the sprouting process, where the eyes of the potato give rise to stolons, is a fundamental aspect. These stolons, when subterranean, develop into new tubers, initiating the energy storage cycle crucial for the plant's survival through the winter.
Now, let's dissect the various methods for cultivating potatoes, as mentioned in the article. Traditional trench planting involves digging furrows, spacing seed potatoes evenly, and subsequently covering them with soil. The method of hilling, or adding soil around the emerging plants, is a distinctive feature in potato cultivation, encouraging root growth without harming the plant.
Container planting, exemplified by the Potato Bag or even garbage cans, presents an alternative approach. The vertical space created by adding soil as the plants grow promotes the formation of more tubers. The anecdote about planting potatoes in a parking stall illustrates the adaptability of the process—layering cardboard, straw, and regularly hilling up the soil resulted in a successful harvest.
The principle of "hilling up" remains constant throughout these methods. Whether in a garden trench, container, or unconventional location, consistently adding soil or suitable material supports tuber development. The use of straw as a hilling material is highlighted for its cooling and moisture-retaining properties.
Additionally, the article provides valuable tips for successful potato cultivation:
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Optimal Conditions: Plant potatoes in full sun, avoiding freshly limed beds. The preferred soil pH is slightly acidic (6.0 – 6.8), with organic matter enhancing crop yield.
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Watering Strategy: Refrain from watering until plants sprout above ground to prevent soil diseases. Once established, maintain even moisture, especially during the blooming stage.
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Harvest Timing: For new potatoes, harvest when plants are in bloom. For storage potatoes, wait until plants wither and turn brown. Leave them in the soil for an additional 3 weeks to firm up skins.
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Storage Tips: Store harvested potatoes in a cold, dark place with good ventilation, above freezing. Avoid washing them, as excess moisture is detrimental to storage.
By adhering to these insights and leveraging my extensive knowledge of potato cultivation, you can significantly enhance your chances of a bountiful harvest.
