How to Grow Potatoes: A Step-by-Step Guide for Cold Climate Gardens

Potatoes are one of the most satisfying crops to grow at home. Whether you have a small urban space, a raised bed, or a vast backyard garden, potatoes are versatile enough to thrive in various settings. However, growing potatoes in a mountain or cool climate garden presents some unique challenges. In this comprehensive guide, we’ll explore how to grow potatoes successfully, focusing on short-season varieties, soil preparation, and techniques like chitting and hilling.

Why Potatoes Are a Cool-Season Crop

Potatoes thrive in cooler temperatures, making them ideal for planting in spring and autumn. In areas with shorter growing seasons, like mountain regions, timing is everything. Potatoes don’t like extreme heat or frost, so aiming for a balance between cool but not freezing temperatures is crucial.

For most cool-climate gardeners, that means planting potatoes in early spring after the last frost or mid to late summer after the hottest days have passed. This balance allows the plants to develop properly before extreme weather hits.

Pro Tip: If you’re unsure about the exact planting window in your region, look for short-season or early-season potato varieties. These mature faster, giving you a better chance of harvesting a healthy crop before the growing season ends.

Choosing the Right Potato Variety to Grow

Mountain and cold-climate gardeners should prioritise early-season potatoes. These varieties are bred to mature in 75 to 90 days, compared to mid- or late-season potatoes that can take up to 120 days to harvest. Our growing seasons simply aren't that long in some places. The breeds that are available for you in your part of the world will be different to mine, but here I look for varieties like:

• Rocket

• Swift

• Jersey Benne

Because our cool season can be shorter than other regions, early-season varieties help maximise your chances of a decent harvest. Most garden centers will label potato varieties by how long it takes to maturity, so it’s easy to pick the right one.

If you want to try a longer season variety, by all means experiment, you might be surprised by what you can grow where you are. You could try planting them in a more shaded spot in your garden in spring to avoid the summer heat.

One big point to mention when it comes to the difference between short-season and mid to late-season crops, short season spuds don't keep. You know how people can store potatoes over the winter to eat outside of the growing season? This can only be done for the mid to late-season varieties. Short-season crops don't have the time to thicken and harden their skin for storing. These ones will keep in the fridge maybe a week or 2, or even better eat them fresh straight from the garden.

Can You Grow Supermarket Potatoes?

A common question I get is whether you can plant potatoes from the supermarket. Technically, yes, potato seeds are literally just potatoes that sprout. However, I strongly recommend using certified seed potatoes instead. Here’s why:

1. Chemical Treatment: Supermarket potatoes can be treated with chemicals to prevent sprouting during storage. These chemicals can linger in the potato and affect its growth or even harm your soil.

2. Pests and Diseases: You don’t know the conditions of the farm where your supermarket potatoes were grown. They could carry diseases or pests that you don’t want to introduce to your garden.

3. Quality Control: Certified seed potatoes are bred and tested to ensure they’re disease-free and ready to plant, giving you a much better chance of success.

Preparing the Soil

Potatoes thrive in light, well-drained soil. If your soil is rocky, compacted, or too heavy with clay, you’ll need to make some improvements to create the right environment for your potato plants. Here’s how:

• Add Organic Matter: Incorporate compost, well-rotted manure, or old autumn leaves to create a looser, friable texture. This helps the soil drain well, which is crucial because potatoes don’t like soggy conditions.

• Improve Drainage: If you have heavy soil, consider creating a raised bed or planting in containers to improve drainage.

Our mountain soils can often be rocky, so improving the soil by adding organic material on top is sometimes easier than trying to dig down through the rocks. Light, loose soil also makes harvesting potatoes much easier, especially if you want to harvest “new potatoes” while the plant is still growing.

Chitting Potatoes for a Head Start

In shorter growing seasons, chitting your potatoes can give you an advantage. Chitting refers to starting the potatoes indoors before planting them in the garden. Here’s how to do it:

• Place your seed potatoes in a warm, dark place like a pantry or closet.

• After a week or two, you’ll notice small sprouts or “eyes” forming on the potatoes.

• Move the potatoes to a light area to strengthen the sprouts without allowing them to get too leggy. Those long leggy tentacles you can sometimes get means they're reaching for the light. Bring them into a bright area to prevent this, it'll make them easier to plant later.

• When the soil temperature outside is 10°C, the sprouted potatoes are ready to plant.

Chitting helps break the potato’s dormancy and allows it to start growing before the outdoor growing season begins. This method is perfect for regions with short growing windows, like the mountains, we can get frost late into our spring so to avoid killing our potato plants, chit them inside and plant out when temps are warmer.

Planting Your Potatoes

Once your potatoes are ready, plant them in the ground or a container. Potatoes are not fussy and can be planted in a variety of ways:

• In-ground: Dig a trench about 30 cm deep, and place your seed potato with the sprouts facing upward. Cover with soil and gradually fill in the trench as the plant grows.

• Containers: If you’re growing in a pot or grow bag, make sure it’s at least 30 cm deep. Place the potato at the bottom, with 5 cm of soil below it, and fill in with soil.

Potatoes love deep soil, and the deeper the soil, the more potatoes you’ll grow. This is because new potatoes form along the stem of the plant as it grows upward.

Hilling your Potatoes

In some potato growing circles you may have heard of a practice called hilling or mounding. This involves covering the plant higher and higher with soil once it reaches about 15 cm tall. By burying the the plant, you encourage it to keep growing upward, which increases the number of potatoes it produces underground.

Hilling also protects the developing potatoes from sunlight, which can cause them to turn green and become inedible.

But, if you are a lazy gardener like me and don't have time for this throughout the growing season, you can just plant them deep to start with and see how you get on. All gardening is an experiment, whatever you do this year, learn from it and find your best way.

Feeding and Watering Potatoes

Potatoes are heavy feeders, so enriching the soil with compost or manure throughout the growing season will keep them happy. Regular watering is also essential, but remember, potatoes prefer moist, not waterlogged, soil.

• Water Deeply: Potatoes have deep roots, so watering deeply encourages strong growth.

• Avoid Waterlogging: Overwatering can cause rot, so ensure that the soil is well-drained, especially after heavy rains.

Harvesting Potatoes

Harvesting potatoes is like digging for buried treasure! If you’re eager to enjoy some early potatoes, you can harvest a few while the plant leaves are still green, these are called new potatoes. Simply dig carefully around the base of the plant and remove a few potatoes without damaging the rest of the plant.

Pro tip: The bigger ones are at the bottom.

For the main harvest, wait until the plant has completely died back, this signals that the potatoes have matured. If your soil is loose and friable you could just reach on in and grab those spuds or if your feeling confident and super careful, you can use a garden fork or spade to gently lift the potatoes from the soil. Potatoes have been accidentally speared or chopped with a stray fork or spade in the past so just be gentle here.

Growing potatoes in a mountain or cool climate garden can be a deeply rewarding experience. By choosing the right varieties, preparing your soil, and using techniques like chitting and planting deep, you’ll ensure a successful potato crop. Whether you’re growing in the ground, in containers, or even in a raised bed, potatoes are a versatile and forgiving crop for cool climates. Now, it’s time to get planting!