December might not seem like the ideal time for gardening, especially when the ground is frozen and the days are short. However, savvy gardeners know that this month offers unique opportunities to get a head start on the upcoming growing season. By sowing seeds in December, you can take advantage of the dormant season to prepare for an early and bountiful harvest in spring and summer. This guide will explore why December is a great time for sowing, the types of seeds you can plant, and the best practices to ensure your garden thrives in the new year.
The Benefits of Sowing Seeds in December
Sowing seeds in December may seem counterintuitive, but it has several advantages that can set your garden up for success. From leveraging the cold stratification process to reducing springtime workload, there are many reasons to consider December sowing.
Taking Advantage of Cold Stratification
Many seeds, particularly those of perennial plants and certain vegetables, require a period of cold to break dormancy. This process, known as cold stratification, mimics the natural conditions that seeds would experience in the wild, where they lie dormant over winter before sprouting in spring.
What is Cold Stratification?
Cold stratification is the exposure of seeds to cold, moist conditions for a specific period, typically ranging from a few weeks to several months. This process triggers biochemical changes within the seeds, preparing them for germination when temperatures warm up.
- Natural Cold Stratification: By sowing seeds in December, you allow them to undergo cold stratification naturally. The cold winter weather provides the ideal conditions for this process, ensuring that seeds are ready to germinate as soon as the soil warms in spring.
- Enhanced Germination Rates: Seeds that have undergone cold stratification often have higher germination rates and produce more vigorous plants. This is particularly important for plants like certain wildflowers, perennials, and trees.
Reducing Spring Workload
Spring is one of the busiest times in the garden, with a multitude of tasks competing for your attention. By sowing seeds in December, you can spread out the workload and reduce the pressure in spring, allowing you to focus on other important gardening activities.
Benefits of Spreading Out the Work
- Time Management: Sowing in December means that come spring, many of your plants will already be established, freeing up time for tasks like transplanting, pruning, and weeding.
- Staggered Planting: By starting some seeds early, you can stagger your planting schedule, ensuring a continuous harvest throughout the growing season.
Getting an Early Start on the Growing Season
One of the most compelling reasons to sow seeds in December is the opportunity to get a head start on the growing season. This early start can lead to earlier harvests, longer blooming periods, and a more productive garden overall.
The Advantages of Early Sowing
- Earlier Harvests: Vegetables sown in December can be ready for harvest weeks earlier than those planted in spring. This is particularly beneficial for crops with a long growing season, such as tomatoes and peppers.
- Extended Blooming Period: Flowers sown in December will often bloom earlier and continue flowering for longer, providing extended beauty in your garden.
- Stronger Plants: Plants that have had more time to establish roots before the growing season begins are typically stronger and more resilient to pests, diseases, and environmental stresses.
Making Use of Indoor and Protected Sowing
December is not the time to sow directly in the garden, especially in colder climates. However, by utilizing indoor sowing methods or protected environments like greenhouses and cold frames, you can create the ideal conditions for seed germination.
Indoor Sowing Techniques
- Seed Trays and Pots: Sowing seeds in trays or pots indoors allows you to control the environment, providing consistent warmth, moisture, and light. This method is ideal for starting tender annuals, vegetables, and herbs.
- Grow Lights: If natural light is limited, grow lights can supplement or replace sunlight, ensuring that your seedlings get the light they need to thrive.
- Heating Mats: Using heating mats can help maintain the ideal soil temperature for germination, especially for heat-loving plants like peppers and tomatoes.
Using Greenhouses and Cold Frames
- Greenhouses: A greenhouse provides a controlled environment that protects young plants from the harsh winter weather while allowing them to benefit from natural light. It’s ideal for starting a wide range of seeds in December.
- Cold Frames: A cold frame is a simple structure that uses solar energy to create a microclimate. It can be used to sow hardy seeds that benefit from cold stratification while providing some protection from the elements.
What to Sow in December
Not all seeds are suitable for sowing in December, but there are many that thrive with an early start. This section will cover the types of seeds that can be sown in December, including vegetables, flowers, and herbs, and how to care for them.
Vegetables to Sow in December
Sowing vegetables in December allows you to get a jump on the growing season, with some crops ready for harvest as early as spring. Here are some of the best vegetables to sow this month.
1. Onions and Shallots
Onions and shallots are hardy crops that benefit from an early start. By sowing them in December, you give them plenty of time to establish roots before the growing season begins.
- Varieties: Choose overwintering varieties such as ‘Senshyu Yellow’ for onions and ‘Golden Gourmet’ for shallots.
- Sowing Method: Sow seeds in modules or small pots indoors, or directly in a greenhouse. Transplant the seedlings outdoors in early spring.
- Care: Keep the soil moist but not waterlogged, and ensure the seedlings receive plenty of light.
2. Broad Beans
Broad beans are another crop that can be sown in December for an early harvest. These hardy legumes can withstand cold temperatures and will be ready to harvest in early summer.
- Varieties: ‘Aquadulce Claudia’ is a popular variety for autumn and winter sowing.
- Sowing Method: Sow seeds directly in a greenhouse or cold frame, or start them in pots indoors.
- Care: Water regularly and protect young plants from frost with cloches or fleece if necessary.
3. Peas
Peas can also be sown in December, especially if you’re looking for an early crop. They are relatively hardy and can establish over winter, providing a bountiful harvest in spring.
- Varieties: ‘Feltham First’ and ‘Meteor’ are excellent choices for winter sowing.
- Sowing Method: Sow seeds in a greenhouse or cold frame, or start them indoors in pots.
- Care: Ensure the seedlings have adequate support as they grow, and water regularly to keep the soil evenly moist.
4. Winter Lettuce
Winter lettuce varieties are well-suited to December sowing, providing fresh greens when little else is available. These lettuces can be grown in a greenhouse or cold frame for a continuous supply throughout the winter.
- Varieties: ‘Winter Density’ and ‘Arctic King’ are ideal for winter growing.
- Sowing Method: Sow seeds directly in a greenhouse or cold frame, or start them in trays indoors.
- Care: Thin the seedlings to allow room for growth, and water regularly to prevent the soil from drying out.
Flowers to Sow in December
Many flowers can benefit from an early start, particularly those that require cold stratification or have long growing seasons. Sowing these flowers in December can lead to earlier blooms and more robust plants.
1. Sweet Peas
Sweet peas are a classic garden flower that can be sown in December for early flowering. These fragrant, climbing plants are a favorite for cutting gardens and borders.
- Varieties: ‘Old Spice Mixed’ and ‘Matucana’ are popular for their strong fragrance and vibrant colors.
- Sowing Method: Sow sweet pea seeds in pots indoors or in a cold greenhouse. They can be transplanted outside in spring.
- Care: Soak the seeds overnight before sowing to improve germination. Provide support as the plants grow, and pinch out the tips to encourage bushier growth.
2. Hardy Annuals
Hardy annuals such as calendula, cornflowers, and larkspur can be sown in December for an early start. These flowers are capable of withstanding cooler temperatures and will bloom earlier than spring-sown seeds.
- Varieties: Choose hardy varieties like ‘Pot Marigold’ (calendula), ‘Blue Boy’ (cornflower), and ‘Giant Imperial’ (larkspur).
- Sowing Method: Sow seeds in trays or pots indoors, or directly in a cold frame or greenhouse.
- Care: Keep the soil moist and provide good air circulation to prevent damping off. Transplant the seedlings outdoors in spring when the risk of frost has passed.
3. Perennials
Perennial flowers often benefit from cold stratification, making December an ideal time to sow their seeds. Starting them early gives them time to establish strong roots before they begin flowering.
- Varieties: Consider perennials such as echinacea, lupines, and delphiniums for December sowing.
- Sowing Method: Sow seeds in trays or pots indoors, using a cold stratification method if necessary. Some seeds may benefit from being sown outdoors in a cold frame.
- Care: Keep the soil moist but well-drained, and ensure the seedlings have plenty of light. Transplant the perennials into the garden in late spring or early summer.
Herbs to Sow in December
Herbs are a great addition to any garden, and many can be sown in December for an early start. While some herbs require warmer temperatures to germinate, others can be started indoors during the winter.
1. Parsley
Parsley is a hardy herb that can be sown in December for a spring harvest. It’s slow to germinate, so starting it early gives you a head start.
- Varieties: ‘Italian Flat Leaf’ and ‘Curled Leaf’ are common varieties that perform well in cooler temperatures.
- Sowing Method: Sow seeds in pots indoors or in a greenhouse. Parsley can also be grown in cold frames.
- Care: Keep the soil moist and provide plenty of light. Parsley prefers cool temperatures, so avoid placing it in a too-warm location.
2. Chives
Chives are another herb that can be started in December. These perennial herbs are easy to grow and add a mild onion flavor to a variety of dishes.
- Varieties: ‘Common Chives’ and ‘Garlic Chives’ are both suitable for winter sowing.
- Sowing Method: Sow chive seeds in pots or trays indoors, or directly in a greenhouse or cold frame.
- Care: Water regularly and ensure the seedlings receive plenty of light. Chives can be transplanted outdoors in spring once the risk of frost has passed.
3. Thyme
Thyme is a hardy perennial herb that can be sown in December for an early start. It’s well-suited to indoor growing during the winter and can be transplanted outdoors in spring.
- Varieties: ‘English Thyme’ and ‘Lemon Thyme’ are popular choices for home gardens.
- Sowing Method: Sow thyme seeds in pots indoors or in a greenhouse. Thyme seeds are tiny, so surface sowing is often recommended.
- Care: Keep the soil lightly moist and provide plenty of light. Thyme prefers well-drained soil, so avoid overwatering.
Best Practices for Sowing in December
Sowing seeds in December requires some specific considerations to ensure success. From managing temperature and light to preventing common problems like damping off, these best practices will help you get the most out of your winter sowing efforts.
Managing Temperature and Light
Temperature and light are critical factors in seed germination and seedling growth. In December, when natural light is limited and temperatures are cold, it’s essential to create the right conditions for your seeds.
Temperature Control
- Indoor Temperature: Maintain a consistent temperature in your indoor growing area, ideally between 65-75°F (18-24°C) for most seeds. Use heating mats if necessary to keep the soil warm.
- Greenhouse Temperature: In a greenhouse, monitor the temperature closely. Use a heater or insulation to maintain warmth, especially during the night.
- Cold Frame Management: In a cold frame, ensure that the temperature doesn’t drop too low. Vent the frame on warmer days to prevent overheating and close it at night to retain heat.
Light Requirements
- Natural Light: Place your seedlings in a south-facing window or under grow lights to provide sufficient light. Most seedlings need at least 12-16 hours of light per day to thrive.
- Supplemental Lighting: If natural light is insufficient, use full-spectrum grow lights to supplement. Position the lights close to the seedlings to prevent them from becoming leggy.
Preventing Damping Off
Damping off is a common problem in seedling cultivation, caused by fungal pathogens that thrive in cool, damp conditions. Preventing this issue is crucial for successful sowing in December.
How to Prevent Damping Off
- Soil Sterilization: Use sterile seed-starting mix or sterilize your soil by baking it in the oven at 180°F (82°C) for 30 minutes.
- Good Air Circulation: Ensure good air circulation around your seedlings to prevent the conditions that favor fungal growth. Use a small fan if necessary.
- Proper Watering: Water from the bottom by placing pots in a tray of water, allowing the soil to absorb moisture without wetting the leaves. Avoid overwatering and allow the soil surface to dry slightly between waterings.
- Fungicide Use: Consider using a fungicide specifically designed to prevent damping off. Apply it according to the manufacturer’s instructions if you notice early signs of the disease.
Hardening Off Seedlings
Before transplanting your December-sown seedlings outdoors, it’s important to harden them off. This process gradually acclimates them to outdoor conditions, reducing transplant shock and improving survival rates.
How to Harden Off Seedlings
- Timing: Begin hardening off your seedlings about two weeks before you plan to transplant them outdoors.
- Gradual Exposure: Start by placing the seedlings outside in a sheltered, shady spot for a few hours each day, gradually increasing their time outside and exposure to direct sunlight.
- Protection: Bring the seedlings indoors at night, especially if temperatures are still cool. After about a week, the seedlings should be ready to stay outside full-time.
Conclusion
Sowing seeds in December is a strategic way to get a head start on your garden, taking advantage of the winter months to prepare for a bountiful and beautiful growing season. Whether you’re sowing vegetables, flowers, or herbs, the benefits of early sowing are clear: earlier harvests, stronger plants, and a more productive garden. By following the best practices outlined in this guide and choosing the right seeds for December sowing, you can ensure that your garden is ready to burst into life when spring arrives. With careful planning and attention to detail, December sowing can become a rewarding part of your gardening routine, setting the stage for success in the new year.
