Potato plant care: fertilising, pruning & earthing up potatoes

Regina

I studied horticultural sciences at university and in my free time you can find me in my own patch of land, growing anything with roots. I am particularly passionate about self-sufficiency and seasonal food.

Favourite fruit: quince, cornelian cherry and blueberries
Favourite vegetables: peas, tomatoes and garlic

Caring for potatoes does not take much effort and can lead to a rich harvest. Here are our top tips on watering, fertilising, propagating and caring for the humble potato.

Potato mounding — Mounding plays an important role in the care of potatoes [Photo: withGod/ Shutterstock.com]

Potatoes (Solanum tuberosum) are a popular plant. They are often grown in a veg patch, but also work well in plant pots and on balconies. Just like any plant, though, potatoes do need a little care and attention. The tubers grow best when they are offered the right amount of water, nutrients and earth, and so a little care will go a long way. Here is everything you need to know about caring for and propagating a potato plant.

Contents

Do you need to water potatoes?
Earthing up potatoes
Fertilising potatoes
Pruning potato plants
Overwintering potatoes
Propagating potatoes

Do you need to water potatoes?

Potatoes need plenty of moisture to form tubers. However, do consider the weather and soil type: sandy, permeable soils tend to need more water than heavier, loamy soils. You will know if your potatoes need more water by looking at their foliage. Potato leaves droop when the plant is dehydrated. If you see this, react quickly and water your plants; potatoes can be quite sensitive.

As with many plants, it is best to water potatoes early in the morning so that the plants can absorb as much water as possible before the afternoon heat. It is also a good idea to spread a layer of mulch between the rows of plants. This will not only reduce evaporation, but provide food for organisms in the soil and reduce weed growth.

Tip: If, after watering your potato plants, their leaves are still wilting, the plants may be suffering from root and stem damage, or reacting to an infestation of disease or pests.

Potato plants surrounded by a layer of plant mulch — A layer of mulch on the potatoes helps reduce evaporation and can suppress weed growth [Photo: Nadzeya Pakhomava/ Shutterstock.com]

Earthing up potatoes

Earthing up your potatoes is essential. Piling up soil around the base of your plants protects them from excessive sunlight, prevents the tubers from producing toxic solanine and turning green, and reduces weed growth. Depending on how vigorous your potatoes are, pile up some soil to the tip of the potato shoot every 2 to 4 weeks.

Fertilising potatoes

Potatoes are medium to vigorous growers, and so require plenty of nutrients to grow healthy foliage and produce a good yield. However, the starchy tubers are sensitive to excess nitrogen, so fast-acting mineral fertilisers are not ideal. Instead, reach for slow-acting, natural fertilisers, which release their nutrients over several months or years.

To fertilise potatoes, work mature compost or manure into your potato bed in spring. A slow-release fertiliser, such as our Plantura Tomato Food, is also a perfect addition to the substrate, and works well for both potted and garden potatoes. You can find more helpful tips in our article on fertilising potatoes.

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Tip: Green manure, which dies from frost in winter, is an ideal crop to plant before your potatoes. It can be worked into the soil in spring and provides food for microorganisms throughout the year.

Pruning potato plants

There is no need to prune healthy potato plants. They need plenty of leaves to produce the sugars that are later stored as starch in the tubers. The exception to this rule, however, is early leaf disease, which can be curbed by removing the diseased leaves.

Overwintering potatoes

Potato plants die naturally when their tubers ripen in autumn. The tubers then overwinter in the soil and sprout fresh new shoots the following year. However, they will not do so if winter is too harsh; frosts severely damage sensitive tubers. As such, it is best to harvest before winter, and store the potatoes in a cool, frost-free location, like a cellar or garden shed.

Overwintered daughter tubers — Overwintered tubers offer a simple way to propagate the same variety of potatoes again [Photo: Ekaterina Iatcenko/ Shutterstock.com]

Propagating potatoes

Propagating potatoes can be done with both a potato tuber and seed. However, growing a potato plant directly from seed can take a long time and is only worthwhile for commercial growers. In their first year, plants grown from potato seed produce tiny tubers, which must be replanted the following year to produce a yield comparable to that of the plants propagated from tubers.

As such, it is best to propagate potatoes from tubers. It is the simplest method, and produces genetically identical harvests. After successfully overwintering your tubers, plant them from April.

After weeks of care, your potatoes will be ready to harvest in summer or autumn, depending on the variety. Read our article on harvesting potatoes for helpful tips on how to get the nutritious tubers out of the ground without damaging them.