Is September the Right Time for Planting Leeks?
Yes, you can plant leeks in September. While many gardeners associate leek planting with spring, autumn planting, particularly in September, offers distinct advantages for specific leek varieties and gardening goals. This timing is often ideal for overwintering varieties that mature later, providing a staggered harvest throughout the spring and early summer months. By planting in September, you allow the young plants to establish a robust root system before the coldest weather sets in, setting them up for strong growth when the temperatures rise again.
- September planting is suitable for overwintering leek varieties.
- Allows for root establishment before winter frost.
- Provides a staggered harvest in spring/early summer.
- Requires specific variety selection for best results.
The decision to plant leeks in September hinges on the variety you choose and your climate. Early maturing types or those specifically bred for overwintering are best suited for this late-season planting. These varieties are typically hardier and can withstand cooler temperatures, benefiting from the longer growing period that begins after winter. Understanding the specific needs of your chosen leek cultivar is paramount to ensuring a successful crop when planting outside of the typical spring window.
Choosing the Right Leek Varieties for September Planting
Not all leek varieties are created equal when it comes to autumn planting. You'll want to focus on 'overwintering' types. These are bred for their resilience against colder weather and are designed to stay in the ground through winter, developing slowly before a rapid growth spurt in spring. Examples include 'Musselburgh', a classic hardy variety, or 'Kingussie', known for its excellent winter hardiness. Varieties like 'Autumn Giant' might be too early for a September planting if you're aiming for a spring harvest, as they are intended for earlier maturity. Always check the seed packet or plant label for descriptions that indicate winter hardiness and suitability for overwintering.
Benefits of Planting Leeks in September
Planting leeks in September offers a strategic advantage by extending your harvest season. Instead of a single flush of leeks, you can achieve a more continuous supply. Leeks planted in autumn will overwinter and begin growing vigorously as soon as the soil warms in early spring. This means you can start harvesting them from late spring through to early summer, well before your spring-sown crops are ready. It also means less competition for space in your garden during the busy spring planting period. Furthermore, young plants established in September are often more robust than those started later, potentially leading to healthier, more productive mature plants.
How to Plant Leeks in September Successfully
To ensure your leeks thrive when planted in September, proper preparation and planting techniques are essential. The soil should be well-drained and enriched with organic matter, such as compost or well-rotted manure. This provides the nutrients leeks need for healthy development and aids in drainage, which is critical to prevent root rot over winter. The planting depth is also important; while leeks benefit from blanching (earthing up the stem to make it white and tender), they should be planted deeper initially than you might expect, often in trenches or deep holes, allowing for gradual earthing up as they grow.
Preparing the Planting Site
Before you begin planting, prepare your leek bed. Loosen the soil to a good depth, ideally around 20-30 cm, to allow for root penetration and drainage. Incorporate a generous amount of compost or aged manure. This will not only feed the plants but also improve soil structure, making it more workable and less prone to waterlogging. If your soil is heavy clay, adding grit or sand can improve drainage. For September planting, ensuring the site is relatively free from perennial weeds is also a good idea, as they can compete with the young leeks throughout the autumn and winter.
Dig planting holes or shallow trenches about 15-20 cm deep. This depth allows you to plant the leeks' stems deeper, encouraging more blanching later and protecting the base from early frosts.
Planting Procedure and Spacing
When planting young leek plants (or 'sets' if you've started them from seed indoors), space them adequately. For most varieties, aim for a spacing of 10-15 cm between plants within a row, with rows set about 30-45 cm apart. This provides sufficient room for the leeks to develop their characteristic thick stems and ensures good air circulation, reducing the risk of disease. Place each leek into its hole or trench, covering the roots and a portion of the lower stem with soil. Do not firm the soil too aggressively; a gentle watering will help settle it around the roots.
Initial Care After Planting
After planting, give the leeks a thorough watering. This helps to settle the soil and reduce transplant shock. Keep the soil consistently moist, especially during any dry spells in early autumn. Mulching around the base of the plants with a layer of straw or compost can help retain moisture, suppress weeds, and insulate the soil, offering some protection against temperature fluctuations. Continue to water regularly until the ground begins to cool significantly, promoting establishment before winter.
Caring for Overwintering Leeks
Once your leeks are planted in September, the focus shifts to ensuring they survive the winter and are ready for spring growth. The main task during autumn is to keep them watered and weed-free. As temperatures drop, leeks naturally slow down their growth, but they still require attention. Protecting them from severe frost might be necessary in colder regions, though most overwintering varieties are quite hardy.
The Art of Blanching and Earthing Up
Blanching is a key technique for producing tender, white leek stems. As your leeks grow taller, you will gradually draw soil up around the base of the stems. This process, known as earthing up, excludes light from the lower part of the stem, encouraging it to remain pale and tender. For leeks planted in September, you can begin this process in late autumn, especially if you planted them in trenches. Continue earthing up in early spring as the plants start their main growth spurt. Aim to cover about two-thirds of the leek's length for optimal results. This is a gradual process, done in stages to avoid damaging the plants.
The success of planting leeks in September lies in selecting the right varieties and providing them with the protection and care they need to establish before winter, ensuring a rewarding spring harvest.
Winter Protection and Feeding
While overwintering leek varieties are hardy, very harsh winters can still pose a risk. In areas prone to severe cold or prolonged freezing, a thick mulch of straw, bracken, or compost around the base of the plants can offer insulation. This helps protect the roots from extreme cold. Leeks are relatively heavy feeders, but it’s generally best to avoid excessive feeding late in autumn. A good start with nutrient-rich soil is often sufficient. If you notice slow spring growth, a balanced liquid feed can be applied in early spring once growth resumes.
Pest and Disease Management
Leeks can be susceptible to pests like the leek moth and diseases such as rust. Good garden hygiene, proper spacing, and ensuring good air circulation help mitigate these issues. Planting in September and encouraging strong early establishment can lead to healthier plants that are more resistant. Keep an eye out for any signs of trouble and address them promptly. For instance, removing affected leaves or using appropriate, environmentally friendly pest control measures as needed.
If you've planted leeks in trenches, use the soil from the trench itself for initial earthing up, then supplement with fresh compost or soil as needed, working from the sides towards the plants.
Alternatives to September Leek Planting
While September planting is a viable and beneficial option for certain leek varieties and harvest schedules, it's not the only way to grow these versatile alliums. Understanding alternative planting times can help you manage your garden space and harvest throughout the year, ensuring you always have this culinary staple at hand. These alternatives cater to different climate conditions and gardener preferences.
Spring Planting: The Traditional Approach
The most common time to plant leeks is in early to mid-spring. This is typically from March through May, depending on your local climate and soil conditions. Spring planting allows leeks to benefit from the full growing season, developing into large, mature plants by autumn and winter. Varieties suitable for spring planting include those bred for autumn or winter harvest, which will mature after a long growing period. This method is often favoured by gardeners who want to harvest leeks during the colder months when other greens might be scarce. It’s a straightforward approach that requires less concern about overwintering.
Late Summer Sowing for Autumn Harvest
For an earlier harvest, consider sowing leek seeds or planting out young leeks in late summer, perhaps August. This timing is ideal if you want to harvest leeks from late autumn into early winter. The plants benefit from warm soil and long daylight hours, leading to rapid growth. However, this timing might require selecting varieties that mature more quickly. If you're in a region with very mild winters, these leeks may also overwinter and continue to produce into spring. This method is a good way to fill a gap if your spring-planted leeks are used up.
Starting Leeks Indoors
Regardless of when you plan to plant them outdoors, starting leek seeds indoors several weeks before the last frost date is a common and highly recommended practice. This gives the slow-growing leeks a head start, producing stronger, more robust seedlings for transplanting. You can sow seeds in modules or trays filled with seed compost. Once the seedlings have developed true leaves and the risk of hard frost has passed for your spring planting, or when you are preparing for your September planting, they are ready to be transplanted into their final growing positions.
What If You Missed the September Window?
If you've missed the September planting window for overwintering varieties, don't despair. Your primary alternative is to proceed with spring planting. You can purchase young plants or sow seeds indoors as soon as conditions permit in early spring. This will ensure a harvest later in the year, typically from late summer through autumn and into winter, depending on the variety. Focus on choosing varieties suited for spring planting and a long growing season to maximise your yield for the upcoming year.