Is It Too Late To Plant Potatoes?

Planting potatoes late in the season can still yield a successful harvest if you choose the right varieties and take steps to protect them from cold weather.

Understanding the growing season, managing frost risks, and using practical techniques like mulching and container gardening can help you enjoy a healthy potato crop even when planting later than usual.

Published: September 30, 2024.

These dates are general guidelines and may vary slightly depending on local conditions. Early-maturing varieties are often the best choice for late-season planting across all zones.

The dates provided are for planting seed potatoes, which are small potato tubers or pieces of tubers that have "eyes" or buds from which the plant will sprout. Seed potatoes are typically used for growing new potato plants, as opposed to planting actual potato seeds, which are less common in home gardening due to their longer germination and growth time.

If you're using sprouted seed potatoes, the planting time may be slightly later or aligned with the given dates, as sprouted potatoes are already in the early stages of growth and will establish more quickly.

On the other hand, planting potato seeds (from true potato seeds) requires a longer growing period, as the seeds need to germinate and develop into tubers, which may not fit within late planting schedules.

And now, here's a little bit longer answer...

Understanding the Potato Growing Season

The growing season for potatoes largely depends on the region and climate, but there are general guidelines that can help gardeners plan when to plant. Typically, potatoes thrive in cool-weather conditions, making early spring the ideal time to plant in most areas.

Potatoes prefer soil temperatures of around 45–55°F (7–13°C) for successful sprouting, and they need a consistent growing period of 90–120 days to mature fully.

In regions with a temperate climate, the typical planting time is between late March and early April. In warmer areas, planting can occur earlier, around February, to avoid the hottest months, as high temperatures can stunt potato growth and yield. Conversely, in cooler regions with shorter summers, planting may need to happen later in spring, around May, to ensure the frost has passed, but before the growing season gets too short.

Ideal soil conditions are also very important for potato planting. Potatoes do best in loose, well-draining soil with a slightly acidic pH between 5.0 and 6.5. Dense or poorly drained soil can cause waterlogging, leading to rot or disease.

When these conditions are met, you can expect an excellent potato harvest.

However, if you missed the optimal window, there may still be time, depending on the factors discussed below.

Factors That Affect Late Potato Planting

Several factors determine whether it's too late to plant potatoes in your area. Understanding these can help you assess the feasibility of a late-season crop.

Climate and Frost Dates

One of the most critical factors in deciding whether to plant potatoes late in the season is your region’s climate and frost dates.

Potatoes are sensitive to frost, and planting them too late may not give them enough time to mature before the first autumn frost hits.

Use a frost date calculator to determine your region’s first frost date and ensure you have at least 90 days (variety dependant!) from planting to harvest.

However, in warmer regions, a second crop may be possible by planting in late summer, with a harvest before the first frost of winter.

Soil Temperature

Potatoes need soil temperatures to be at least 45°F (7°C) for healthy tuber development. If the soil is too cold, the potatoes will not sprout properly, and if the temperature is too high (over 80°F or 27°C), growth may be inhibited.

Late planting is still possible as long as the soil temperature remains in the ideal range. If you live in a cooler region and the summer heat has passed, but soil temperatures are still favorable, you might be able to plant a late crop successfully.

Sunlight Availability

Potatoes need full sun for a minimum of 6 hours a day to grow well. As the season progresses into late summer or early fall, days become shorter, which can impact plant development. When planting late, ensure that your garden or growing area receives adequate sunlight, or consider alternative growing methods like containers that can be moved to maximize sun exposure.

Growing Season Length

The length of the growing season in your region plays a significant role in whether late planting is feasible. Potatoes generally need at least 90 to 120 frost-free days to mature fully, though some early-maturing varieties may take as little as 70 days.

If you have a shorter growing season but can still plant with enough time before frost, opting for a fast-growing variety may help ensure a successful harvest.

Considering these factors, especially the climate, soil temperature, sunlight, and the overall growing season, you can make an informed decision about whether it's too late to plant potatoes.

Additionally, using techniques like covering crops with row covers or mulch may extend the growing season slightly, giving late-planted potatoes a better chance of maturing before frost.

Late-Season Potato Varieties

If you find yourself planting potatoes later than the recommended time, selecting the right potato variety is key to success. Some potato varieties are better suited for late planting due to their shorter growing periods and tolerance to cooler or warmer conditions.

Early-Maturing Varieties

For late planting, it’s best to choose early-maturing varieties that can grow and produce a harvest in as little as 70–90 days. These varieties tend to have a shorter lifecycle, making them ideal for gardeners who are trying to squeeze in a crop before the end of the growing season.

• 'Yukon Gold': Known for its buttery flavor and smooth texture, Yukon Gold matures in about 70–90 days, making it one of the best options for late planting. It's also relatively tolerant of cool temperatures.
• 'Red Norland': Another early-maturing variety, Red Norland potatoes take around 70–90 days to mature and can thrive in both cool and warmer climates. They are also resistant to scab, a common potato disease.
• 'Caribe': This early variety grows in around 70 days and is highly resistant to cold, making it an excellent choice for gardeners in cooler regions who are planting late in the season.

Advantages of Early Varieties for Late Planting

The primary advantage of these early varieties is their ability to mature before the first frost in cooler regions or to avoid the harshest heat in warmer climates.

These varieties also tend to have good disease resistance and are less likely to encounter growth issues due to reduced daylight hours in the late growing season. For gardeners who want a late-season harvest, these varieties provide a reliable option for getting crops before winter arrives.

Consideration for Warmer Climates

In warmer climates, where the growing season can be extended into fall, some mid-season varieties can also be planted later. Varieties like 'Kennebec' or 'Maris Piper' can still thrive if planted in late summer, as long as they are harvested before the first frost.

Climate Considerations: Cool vs. Warm Regions

Climate is a major factor in determining whether it's feasible to plant potatoes late in the season. Different climates offer unique challenges and opportunities for late-season potato planting.

Cool Regions

In cooler climates, such as those in northern Europe, Canada, or the northern United States, potatoes are generally planted in early spring, shortly after the last frost. However, late-season planting can still be successful in these regions if the weather conditions allow for at least 70–90 frost-free days before the first autumn frost.

The primary concern in cooler regions is that soil temperatures drop too low before the potatoes can fully mature.

To combat this, gardeners can use row covers or mulches to help insulate the soil and extend the growing season. Additionally, early-maturing varieties, like 'Yukon Gold' or 'Red Norland,' can be a good choice, as they mature quickly and are more tolerant of cooler soil conditions.

Another factor in cool regions is the length of daylight, which decreases significantly as the season progresses. Potatoes planted later in the year will receive less sunlight, which can slow growth. Gardeners may need to monitor sunlight exposure carefully to ensure the plants receive enough energy to develop healthy tubers.

Warm Regions

In warmer climates, such as the southern United States, southern Europe, or areas with Mediterranean-like weather, the growing season is typically longer, and potatoes can often be planted in late summer or early fall for a second crop.

The key in these regions is to plant after the hottest part of summer has passed, as potatoes do not tolerate extreme heat well.

Late planting in warm climates can be highly successful as long as the soil temperature stays within the ideal range of 45–80°F (7–27°C). One benefit of warm climates is that frost is not as immediate a concern, giving gardeners more flexibility with planting times. Some mid-season potato varieties can thrive in these conditions, providing an extended growing period for a second harvest in late fall.

In areas where winters are mild, gardeners can plant potatoes later in the season and still expect a full harvest. However, keeping the plants well-watered and shaded during particularly hot days is essential to prevent heat stress and tuber damage.

Transitional Climates

In regions with transitional climates - those that experience both warm and cool periods, such as parts of the central United States - timing becomes critical for late potato planting. In these areas, the growing season might allow for late summer planting, but gardeners need to be mindful of both the late summer heat and the onset of cooler fall temperatures.

For transitional regions, selecting early-maturing or heat-tolerant varieties is essential. Additionally, using mulch or other protective measures to manage soil temperature and moisture levels can help extend the growing season and ensure a healthy potato crop.

Frost Dates and Late Potato Planting

Frost dates play a critical role in determining the success of your potato planting, especially if you’re planting late in the season. Potatoes are highly sensitive to frost, particularly in the early stages of growth, and frost damage can severely impact yield or even kill young plants.

How to Calculate the First Frost Date

The last frost date refers to the approximate date in spring when your region is expected to experience its final frost, while the first frost date in fall marks when frost is likely to occur again. Both are vital for planning a potato crop, especially for late planting.

To calculate these dates for your area, there are several reliable resources available, however, perhaps the most reliable ones are Local Agricultural Extension Offices - most regions have local agricultural offices that publish frost dates, which are often more accurate than general calculators because they take microclimates into account.

Once you have your last frost date, you can count backward to figure out the best planting window. Ideally, you should plant potatoes when you have enough time for the potatoes to mature before the first frost in fall.

Note: it is good practice to have a few extra weeks added... better safe than sorry...

Frost Protection Strategies for Late Planting

If you are planting potatoes late in the season, it’s essential to plan for the possibility of an early frost. Some effective methods to protect your crop from frost include:

• Mulching: Applying a thick layer of organic mulch around the base of potato plants can help insulate the soil and protect the tubers from light frost.
• Row Covers: Using fabric row covers or frost blankets can shield plants from cold temperatures during sudden frost events. These are especially useful for late-season planting.
• Greenhouses: If frost is a major concern, growing potatoes in a protected environment like a greenhouse can extend the growing season and prevent frost damage.

Growing Potatoes in Containers: A Late-Season Option

For gardeners who missed the traditional planting window or want to extend the growing season, container gardening offers an excellent solution.

Growing potatoes in containers allows you to control the environment more closely, which can be beneficial for late-season planting when weather conditions are less predictable.

Advantages of Growing Potatoes in Containers

Growing potatoes in containers offers several advantages, particularly for late planting:

• Mobility: Containers can be moved to take advantage of better sunlight or to protect plants from frost. This flexibility is especially helpful in late-season gardening, where sudden weather changes can threaten crops.
• Soil Control: Container gardening allows you to control the soil conditions more effectively. You can ensure the soil is well-draining, has the correct pH, and remains at the right temperature, even if outdoor soil conditions are not ideal.
• Frost Protection: If frost becomes a threat, containers can be brought indoors or into a sheltered area to protect the plants. This makes containers a particularly good option for regions where the first frost date might arrive sooner than expected.
• Extended Growing Season: By growing potatoes in containers, you can plant later than you would in a traditional garden bed. The controlled environment of the container helps mitigate some of the risks associated with late-season planting.

Best Practices for Growing Potatoes in Containers

To grow potatoes successfully in containers, follow these key steps:

• Choose the Right Container: Potatoes need plenty of room to develop their tubers. Select a container that is at least 12–15 inches deep and wide. Ensure it has good drainage holes to prevent waterlogging, as potatoes do not tolerate soggy soil.
• Prepare the Soil: Fill the container with loose, well-draining soil. You can use a mix of garden soil and compost or a high-quality potting mix. The soil should be slightly acidic, with a pH between 5.0 and 6.5.
• Plant the Potatoes: Plant seed potatoes about 4–6 inches deep in the container. As the plants grow, gradually add more soil or mulch to the container (a process known as "hilling"), which encourages more tuber development along the buried stems.
• Provide Adequate Sunlight: Place the container in a spot where it will receive at least 6 hours of sunlight per day. If growing indoors or in a greenhouse, ensure the plants get sufficient light by using grow lights if necessary.
• Watering and Fertilizing: Water consistently but avoid over-watering, as this can lead to rot. Container-grown potatoes may require more frequent watering than those in the ground due to the restricted space. Fertilize with a balanced, slow-release fertilizer, or use compost to keep the plants healthy.

Harvesting Potatoes From Containers

One major advantage of container-grown potatoes is that harvesting is much simpler. Once the plants have flowered and begun to die back, you can tip the container over and easily gather the tubers.

This reduces the risk of damaging the potatoes during harvest and makes it easier to grow in smaller spaces.

For more on this topic, feel free to check our Growing Potatoes in Containers article.

Protecting Late-Season Potatoes From Cold

One of the biggest challenges of late-season potato planting is the risk of cold weather, particularly unexpected cold snaps that can harm young plants or delay tuber development.

However, there are several strategies that can help protect your crop and extend the growing season.

Mulching

Mulch serves as an excellent insulator, keeping the soil temperature more stable during fluctuating weather conditions.

Applying a thick layer of organic mulch - such as straw, leaves, or grass clippings - around the base of your potato plants can help shield them from cooler temperatures. Mulch also retains moisture, which is beneficial for late-season crops that may experience drier conditions.

For late-planted potatoes, mulch is especially useful because it prevents sudden temperature drops from reaching the soil, where potato tubers are most vulnerable.

Additionally, as the mulch breaks down, it adds nutrients to the soil, promoting healthy plant growth.

Row Covers

Row covers are another effective method for protecting late-planted potatoes from cold snaps. These lightweight, breathable fabric covers can be draped directly over potato plants, acting as a buffer against cold air and light frost.

The fabric traps heat from the soil, raising the temperature underneath by a few degrees, which can make a significant difference in preserving your crop.

Floating row covers are particularly useful because they allow light and water to pass through, so your plants continue to grow while being protected.

For even greater insulation, you can use frost blankets or plastic tunnels to create a mini greenhouse effect, ensuring that your potatoes remain warm during colder nights.

Harvesting Late-Planted Potatoes

When planting potatoes later in the season, it’s essential to adjust your expectations for harvest time. Late-planted potatoes will follow the same growth pattern as those planted in the regular season, but their timing may differ depending on when you plant and the weather conditions.

Monitoring for Maturity

Potatoes are generally ready for harvest when the plants begin to die back, which signals that the tubers have stopped growing.

For late-planted potatoes, this could occur during cooler fall months, so it’s important to monitor the plants closely. Keep an eye on the foliage, which will turn yellow and start to wither. This is your cue that the potatoes are ready to be dug up.

If the first frost occurs before the plants die back naturally, you can either harvest the potatoes early or take extra measures to protect them from frost while they continue to mature.

Curing Potatoes

Late-season potatoes, like those planted earlier in the year, benefit from a curing process after harvest. After digging up the tubers, allow them to dry in a cool, dark, and well-ventilated area for a week or two. Curing toughens the potato skin, helping to extend their shelf life during storage.

Expectations for Size and Yield

It’s important to note that late-planted potatoes may not reach the same size as those planted earlier in the season. The shorter growing period and cooler temperatures in late fall can affect the size and overall yield of your crop.

However, by using early-maturing varieties and maintaining optimal growing conditions, you can still achieve a satisfactory harvest.

Tips for Success With Late Potato Planting

To increase your chances of a successful crop when planting potatoes late in the season, follow these practical tips:

Soil Preparation

The foundation of any good potato crop is the soil. Before planting late-season potatoes, ensure the soil is well-prepared by loosening it to a depth of at least 12 inches.

Potatoes need loose, well-draining soil to allow their tubers to grow without restriction. Adding compost or well-rotted manure can improve soil structure and provide the nutrients potatoes need to thrive.

If you’re planting in containers, use a high-quality potting mix that drains well, and consider adding perlite or sand to improve aeration.

Watering Techniques

Consistent watering is very important for late-planted potatoes, especially if they are growing during a dry period. Potatoes need a steady supply of moisture to develop healthy tubers, but avoid overwatering, as this can lead to rot.

Water the plants deeply once or twice a week, ensuring the soil remains moist but not waterlogged. Mulching can help retain moisture and reduce the need for frequent watering.

Choosing the Right Varieties

As mentioned earlier, early-maturing potato varieties are your best bet for late planting. These varieties, which can mature in as little as 70–90 days, are well-suited to the shorter growing period of late-season planting. Be sure to select varieties that match your climate and soil conditions.

Fertilizing

To support late-season growth, consider using a balanced fertilizer or organic compost to provide essential nutrients. Fertilize the potatoes about four to six weeks after planting to boost tuber development.

Avoid over-fertilizing, particularly with nitrogen-heavy fertilizers, as this can encourage excessive foliage growth at the expense of tuber production.

Protecting Against Pests

Late-season potatoes are still susceptible to common pests like aphids, potato beetles, and slugs.

Regularly inspect the plants for signs of infestation and use organic pest control methods such as neem oil, diatomaceous earth, or manual removal to keep your plants healthy.

Following these tips and being mindful of soil preparation, watering, and frost protection can help you successfully grow and harvest potatoes even when planting later in the season.

The key is to remain flexible and adjust your gardening practices to accommodate the changing conditions of late summer and early fall.