Timing Your Potato Harvest
Deciding when to harvest potatoes hinges on the variety you're growing and what you intend to do with them. New or 'earlies' are usually ready for lifting around 10 to 12 weeks after planting. Maincrop and late varieties, which are intended for storage, require a longer growing season and might take 15 to 20 weeks or more.
- Early potatoes are ready 10-12 weeks post-planting.
- Maincrop varieties need 15-20+ weeks to mature.
- Harvesting depends on variety and intended use.
- Check foliage for maturity signs.
- Protect tubers from frost.
The most straightforward indicator is often the state of the potato plant's foliage. For 'new' potatoes, you can carefully scrape away some soil around a plant to check the size of the developing tubers. If they are of a satisfactory size for your needs, you can start harvesting. For maincrop varieties destined for storage, it's crucial to let them mature fully. This typically involves waiting until the foliage starts to yellow and eventually die back.
This die-back is a natural signal that the plant has finished its work of producing and maturing the tubers. For maincrop varieties, it's advisable to wait for the tops to have died back completely before considering harvest, especially if you want potatoes that will store well. Harvesting too early can result in immature skins that are easily damaged and won't keep for long. It's also important to avoid harvesting during or immediately after heavy rain, as excess moisture can encourage rot during storage.
A key consideration for timing is avoiding frost. Potatoes are susceptible to frost damage, which can spoil the tubers. If an early frost is forecast and your maincrop potatoes are not yet mature, you may need to lift them prematurely to protect them. However, this will reduce their storage potential.
When to Grow Potatoes and Harvest Early Varieties
For those keen to get a taste of the new season's crop as soon as possible, understanding the growth cycle is paramount. Potatoes are generally planted in early spring, with 'earlies' often going into the ground from March onwards, depending on your local climate and soil conditions. They benefit from warmer soil to begin their growth, but are more tolerant of cooler temperatures than maincrop varieties. This allows them to mature relatively quickly, often being ready for their first taste by early to mid-summer.
The 'new' potato stage is characterised by thin, delicate skins that are easily rubbed off. These are best eaten fresh, shortly after harvesting, as their high moisture content means they don't store well for extended periods. The focus here is on immediate enjoyment rather than long-term preservation.
Recognising Mature Potatoes: Signs to Look For
How can you tell if your potatoes are truly ready? Several visual and tactile cues provide the answer. The most obvious sign for maincrop potatoes is the behaviour of their foliage. When the green leaves and stems begin to turn yellow, wither, and eventually collapse onto the soil, it indicates that the plant's energy reserves are shifting from growth to tuber maturation and dormancy.
For maincrop varieties intended for storage, it is essential to wait for the foliage to die back naturally. This process can take several weeks after the plant stops flowering. Allowing the tubers to mature in the ground after the tops have died off helps to toughen their skins, which is crucial for successful storage. This period is sometimes referred to as curing.
The state of the foliage is the most reliable indicator of maturity for storage potatoes.
For early varieties, the signal is less about dying foliage and more about tuber size. You can gently probe the soil around the base of the plant with your fingers or a small hand fork to check the developing potatoes. If they have reached a size you deem suitable for eating, you can begin harvesting your new potatoes. It's often possible to harvest just what you need, leaving the rest of the plant to continue growing. This staggered harvesting ensures a supply of fresh, young potatoes over a period.
Another subtle, but important, sign related to skin toughness is how easily the skin can be rubbed off. If you gently rub a mature tuber with your thumb and the skin comes away easily, it's likely not fully mature for storage. Conversely, if the skin feels firmly attached and resistant to rubbing, it's a good sign of readiness.
How Long Do Potatoes Take to Grow?
The duration from planting to harvest varies significantly across different types of potatoes. 'First early' varieties might be ready as soon as 9-11 weeks after planting. 'Second early' varieties typically take a little longer, around 11-13 weeks. Maincrop varieties, which are grown for substantial yields and long-term storage, require the longest period, often 15-20 weeks or even more, depending on the specific cultivar and growing conditions.
If you're growing potatoes in pots or growing bags for potatoes, you can often achieve slightly earlier harvests due to the controlled environment and warmer soil temperatures. However, the general principles of checking foliage and tuber development still apply. The key is to observe the plant's progress rather than relying solely on a calendar date.
Methods for Harvesting Potatoes
Once you've determined that your potatoes are ready, the method of harvesting is important for protecting your yield and ensuring good storage. For small gardens or a few plants, a hand fork or trowel is usually sufficient. For larger areas, a spade or even a mechanical potato harvester might be used, though these are less common in home gardens.
The general technique involves carefully inserting your chosen tool into the soil *away* from the main stem of the plant. This minimises the risk of spearing or damaging the tubers. Work your way around the plant, loosening the soil and gently lifting the entire clump of potatoes to the surface. It's common to find potatoes at various depths, so be thorough in your search.
Dig potatoes on a dry, mild day to prevent damage and aid curing.
After lifting, gently brush off excess soil. Avoid washing the potatoes at this stage, as the residual soil actually helps protect the skins during the curing process. If the skins are very dirty, you can use a soft brush or a dry cloth to clean them. If you've harvested new potatoes, their delicate skins mean you should handle them with extra care to avoid bruising or peeling.
For maincrop varieties intended for storage, the next crucial step after lifting is curing. This involves leaving the potatoes in a cool, dark, and well-ventilated place for about one to two weeks. During this time, the skins will harden further, and any minor cuts or bruises will heal, preparing them for longer-term storage. This is a vital step for good storage potential.
Storing Your Harvest
Proper storage is key to enjoying your potato harvest for months. After harvesting and curing, store them in a cool, dark, and dry place. Ideal temperatures are between 7-10°C (45-50°F). Avoid storing them in the refrigerator, as the cold temperature can convert starches to sugars, affecting taste and texture, and causing them to turn dark when cooked. Similarly, avoid warm, humid conditions, which promote sprouting and rot.
Ensure harvested potatoes are completely dry and cured before storing.
Use hessian sacks, crates, or paper bags for storage. Avoid plastic bags, which can trap moisture and lead to spoilage. Check your stored potatoes periodically and remove any that show signs of rot or sprouting to prevent them from affecting the rest of the crop. If you're growing seed potatoes, the same principles of careful handling and appropriate storage apply to ensure they remain viable for the next planting season.
Alternative Potato Harvesting Approaches
While the traditional method of digging up the entire plant at once is standard, gardeners sometimes employ alternative strategies, especially for early varieties or when managing space in smaller plots. One such approach is 'earthing up' throughout the growing season, which not only protects developing tubers from sunlight (preventing greening and solanine formation) but also makes them easier to access later.
For those growing potatoes in bags or containers, harvesting is often a simpler affair. You can often gently tilt the container or reach into the bag to retrieve mature potatoes, leaving younger ones to continue growing. This allows for a more continuous harvest and can be particularly satisfying for home growers.
Another consideration is the type of potato. If you're growing for specific culinary uses, the harvest timing might adjust. For instance, some gardeners might harvest waxy varieties slightly earlier for a salad potato, while leaving floury varieties to mature fully for mashing or roasting.
When to Harvest Potatoes UK Gardens
In UK gardens, the timing for harvesting potatoes is largely dictated by the climate and the specific variety planted, whether from seed potatoes or pre-sprouted tubers. Early potatoes, planted in March or April, can often be ready for lifting from June onwards. Maincrop varieties, planted a little later in April or May, typically mature from August through to October. It is crucial to lift maincrops before the first hard frosts damage the plants and tubers.
The UK's variable weather means that observing the plants is more important than adhering strictly to dates. Wet conditions in autumn can make harvesting difficult and increase the risk of rot, so many growers aim to lift maincrops in drier spells during September or early October. If the foliage has died back and the soil is dry enough, digging can commence. Gardeners often use a fork to loosen the soil and carefully lift the tubers, ensuring they are not damaged during the process.
Understanding your chosen variety's growth habit is key to successful potato harvesting.
When growing potatoes in pots or grow bags for potatoes, UK gardeners can benefit from the controlled environment. This can sometimes lead to slightly earlier harvests compared to open ground, especially in cooler springs, as the soil warms up more quickly. The ease of access also makes it simpler to check on the developing tubers and harvest them as they reach desired sizes.