When to Plant Your Potatoes to Beat the Frost

Potatoes are important in a self-sufficient garden, but we struggled to get a good crop for many years in our short season. In our Zone 2b garden, the last spring frost occurs on May 23rd, which goes back to September 13th. Unless our region gets hit by a snowstorm in the middle of summer, that gives us 113 days of frost-free growth, which can be adequate for many potato varieties.

Potatoes can be planted two to four weeks before the last spring frost when the soil temperature is about 7°C (45°F), and the air temperature is -2°C (28°F) at night. stays higher. When growing in cooler climates, there are several ways to help your potatoes, such as choosing early ripening varieties, germinating potatoes early, planting shallowly and mulching with straw. Use bags or season extensions, and harvest as soon as frost. Air chews.

Time your potato harvest in cool weather.

Potatoes are actually perennial vines from the tropical mountains of South America, and they can easily be grown year-round in temperate regions that don't suffer from frost. However, in northern climates with short seasons, it is important to grow these frost-sensitive plants as annuals and plant the potatoes early to give the buds time to mature before frost kills the plants in the fall.

As a general rule, plant potatoes two weeks before the last spring frost. Potatoes can be planted up to four weeks before the last frost if your soil is dry.

Potatoes are adapted to mountain conditions, and can handle cold temperatures well when young. In fact, soil temperatures over 21 °C (70 °F) seriously inhibit their growth and prevent tubers from starting to appear. Potatoes can be set when the soil temperature is 7°C (45°F), although around 12°C (55°F) is ideal. Young plants sown in early spring can tolerate ambient temperatures between -2°C to 0°C (28°F - 32°F).

What Is the Latest You Can Plant Potatoes?

There must be a enough number of frost-free days for the variety to mature if you want to cultivate potatoes that are full size. Find the "days to maturity" for the variety you're growing, then count from your first expected frost in the fall. Of course, you can sow afterward and still get a good crop of new potatoes.

In our garden, with a mid-September frost, we've planted early season varieties through June and still have great harvests. We put potatoes in in July, and while the high temperatures interfered with tuber development, we had a good crop of young potatoes.

Tips for growing potatoes in northern gardens

When planted in the ground, potato eyes germinate and grow into green, leafy plants that produce flowers and seed-bearing berries. Underground, plants have roots and long underground stems called stolons. The tubers that we eat are formed on the lungs.

Green shoots usually appear within 15 to 30 days and after another 15 to 30 days tubers will start to form. Between 45 and 90 days after buds appear, the plant begins flowering and the corms begin to fill. This is a great page showing the life cycle of a potato plant.

To get a good harvest, there must be enough time between the time of planting and the death of the plant in the fall. If your season is really short, here are seven great ways to help your potatoes ensure a good harvest in the fall:

1. Choose early or medium Season Potatoes

Potatoes are generally divided into three different types: early season, mid season, and late season.

Early Season Potatoes: Early potatoes mature very quickly and are usually ready to harvest about 95 days after the greens first appear. They are best eaten fresh and most have a rich, creamy texture. Their thin skin is not ideal for storage, and they are usually only kept for a month or two. They are sometimes called "initial initials". Some of our favorite early-season potato varieties are Red Norland, Caribe, or Bantje.

Mid-Season Potatoes: Mid-season potatoes mature between 95 and 110 days, with most ready to harvest around 100 days. They are sometimes called "second firsts" and are a good balance of stock and tender meat. Some of the best mid-season varieties are Yukon Gold or Red Pontiac.

Late-Season Potatoes: Late-season potatoes are ideal for long-term preservation since they are often rather big and have a thick peel. They can take between 110 and 160 days for their tubers to fully mature and are frequently referred to as "main crop" potatoes. While most late-season potatoes take too long for short growing seasons, some good varieties to try would be Russet Burbank, Desiree, or Kennebec.

If you have a short growing season, choose early or mid-season varieties so they have enough time to fully ripen before fall.

We did plant late varieties sometimes, and while they did produce a delicious crop, the potatoes were so small, the skins hadn't had time to fully cure, so we overstocked them, not getting much use out of them. Another interesting way to differentiate potato cultivars is determinate or indeterminate. Like most tomatoes, potato plants will produce all of their fruit at once on short (determinate) plants or produce flowers and fruit all season on long (indeterminate) vines.

The ripeness of the potato determines how well the plant produces berries and it doesn't matter to the underground tubers, which is why most seed companies don't mention it. The only way to tell them apart is that most early and middle crops are determinate while the late seasons are generally indeterminate.

2. Sprout potatoes before planting.

When you plant a seed in the garden, you have to wait patiently for that seed to grow. It's the same with potatoes: when planted in the ground, it takes two to four weeks for seed potatoes to send up green sprouts. In a short-season garden, waiting for spring can wreak havoc in fall, and you can kick things off by germinating your own seed potatoes.

Germination, or matting, is the process of allowing potatoes to sprout eyes before planting them. Sprouted potatoes germinate faster than unplanted potatoes, and if your potatoes germinate well, you should see green sprouts emerging from the ground within at least four days after planting.

Growing potatoes is really easy:

Planting potatoes in a sunny location: About 20 days before planting, place the seed potatoes in a bright location. Planting your potatoes in a sunny location will ensure that you get strong, green, and healthy sprouts. You can grow potatoes in the dark, but the resulting growth will be white, long, and less vigorous when planted.

Make sure you have 1-3 eyes per potato: each eye that sprouts will become a stalk above the ground. If you have a lot of eyes on potatoes, you will get a very bushy plant that will grow vegetables at the expense of tubers.

Cut large potatoes into pieces: The seed potatoes do not have to be large. In fact, many growers recommend that the ideal potato seed size should be between 40g and 70g (1.5-2.5 oz). Before planting large potatoes, cut them into pieces, making sure that each piece has at least one eye and that each piece is growing its own plant.

Potatoes can also be grown from seeds but the process is more laborious and time consuming. Make sure to start seed potatoes indoors about 6-8 weeks before transplanting them into the garden.

3. Shallow Planting

Traditionally, potatoes are planted 15 cm to 20 cm (6–8 in) deep. If you live in a cold northern garden, you may still have deep snow in your soil when it comes time to plant your potatoes!

We prefer to plant our potatoes only 8 to 10 cm (3-4 inches) deep. Not only is the soil warmer at this depth, but the plants will emerge faster. If you plant potatoes too deep, they will take longer to sprout, which can delay harvest.

Another benefit of shallow planting is that the potatoes will grow closer to the surface and require less digging when harvesting. Of course, potatoes growing close to the soil surface need some protection, and we find that shallowly planted potatoes grow exceptionally well when covered with straw (see below).

4.  Hill With Straw

Potato beds grow relatively close to the soil surface, and throwing dirt over the plants to protect the tubers, suppress weeds, and (hopefully) encourage a larger crop is an ancient practice.

Potato mashing with straws is gaining popularity for good reason. Not only is thatch light and easy to handle, but it is an excellent weed deterrent and protects and insulates tubers from sun and frost. Perhaps the best feature of straw is its ease of harvesting: Just pull back on the straw, and most of your potatoes will be lying flat on the soil's surface, waiting for you to pick them up.

Cover each potato plant with a large handful of straw once or twice during the growing season. In a few days, the plant will push through the straw and continue to grow.

5. Start Potatoes in Grow Bags

The soil in grow bags heats up much faster than the soil at ground level. You can use this to plant potatoes a week or two before spring unless the air temperature is expected to be very cold.

Many planting bags are suitable for potatoes. A good-sized growth sack is about 45 cm (18 in) long and about 30 cm (12 in) in diameter. Special "potato sacks" have an open flap near the bottom that allows you to return potatoes year-round, or you can recycle using old canvas shopping bags to grow your own potatoes.

Remember that as the soil in grow bags heats up quickly, it also dries out quickly. Be sure to water the grow bags regularly, especially while the tubers are growing, to avoid bursting.

6. Use Season Extension

If you're committed to growing potatoes to maturity in your short-season garden, some form of season extension is probably your best option.

While potatoes can certainly be grown in a greenhouse or tunnel, many growers recommend protecting potatoes with a floating row cover in the fall to prevent frost.

For a free but more labor-intensive option, you can cover your potato plants with an old blanket each night and remove it again in the morning. We've used this method with great success to get our squash to grow well after the first frost, and it will work great with potatoes, too.

7. Harvest immediately.

As a general rule, potato plants can be harvested about three weeks after the first flowering or after the plant has died back in cooler, lower temperatures. However, potatoes are not frost tolerant, and even a light frost will kill these tropical plants. If a potato plant dies from frost, there is a risk that the potato will begin to rot underground, or if it is not cut properly, the potato itself may be damaged by frost. In most cases, it's a good idea to harvest potatoes before they die from frost. Once the plant is dead due to frost, harvest the potatoes as soon as possible.

Remember that all potatoes can be harvested before they are ripe. While they may not be good for storage, you'll have a delicious crop of young potatoes to eat, and they can be canned or frozen for long-term storage.

Potatoes for every garden

Every garden has its own challenges. While northern gardeners may bemoan the early return of potato-wiping frosts, they don't have to battle the same diseases and pests that thrive in warmer climates.

While working in the garden, it is useless to complain about the mess Mother Nature throws at us. We have to do the best we can with what we have, and if you've given up on potatoes in the past, we hope some of these ideas can help you get a tasty harvest, even if you are no matter how short the season.