February Greenhouse Gardening: Your Complete Guide

February marks a pivotal moment in the gardening calendar. While winter’s grip may still be strong, this month brings renewed hope as daylight hours begin to lengthen, offering perfect conditions to kickstart your growing season. Whether you’re an experienced gardener or just starting out, your greenhouse can become a hub of early growing activity.

Preparing Your Greenhouse:

Before diving into planting, it’s essential to prepare your growing space properly.  February presents an excellent opportunity to get ahead on your garden maintenance, particularly when it comes to the ‘tools of the trade’.  Just as a chef ensures their knives are sharp before cooking or a painter cleans their brushes before starting a new canvas, a gardener should take time to inspect and maintain their equipment before the busy growing season begins. Consider performing a thorough assessment of your tools, from pruning shears to spades, removing any rust, tightening loose handles, and applying protective oil where needed. This proactive maintenance in February will pay dividends when spring arrives, ensuring your tools are ready to go.

Greenhouse Maintenance and Cleaning

Before Spring, give your greenhouse a thorough clean to prevent pests, diseases and mould from affecting your plants.  Your greenhouse likely hosted various tender plants over winter, potentially harboring pests like slugs and vine weevils. Start with a thorough clean-down of your space, paying special attention to the glass to maximise available sunlight. Consider using nematode treatments on overwintering pots to control any unwanted visitors.

• Remove dead plants and debris.  Get rid of any old plants, weeds or debris that could harbour pests or disease.
• Wash down surfaces, including shelves, windows and frames, using warm soapy water or a mild disinfectant to eliminate mould, mildew and algae. Please remember to disconnect your rainwater pipes/water butts to avoid any detergents entering your water supply.
• Clean the glass (or polycarbonate) panels to maximise light transmission.  Dust and dirt reduce the amount of sunlight your plants receive.  A soft brush is a good way to do this, or using a washing up sponge with a green scourer on the other side for stubborn areas.
• A power washer is also a good alternative to clean glass and bases. Take care with any gravel inside the greenhouse as it can hit glass and potentially break panes.

Check for Repairs and Gaps

Check the structure for any broken panes, cracks, or gaps in the glazing or framework. Repair or replace damaged areas.

Climate Control

February weather can be unpredictable, with temperatures fluctuating dramatically within 24 hours. On warmer, sunny days, open doors and vents to improve air circulation, but remember to close everything up before sundown. Keep horticultural fleece handy to protect tender plants on particularly cold nights.  If you disconnected your auto openers over the winter, now is a good time to reconnect them, ready for the warmer daytime temperatures.

Water Management

Keep watering cans inside your greenhouse so the water remains at an appropriate temperature for plants. While some overwintering plants like geraniums and fuchsias can remain relatively dry until March, others will need consistent moisture monitoring, especially on warmer days.  Ensure that gutter pipes are connected and they have no leaks.  Add silicone to joints if needed, or replace damaged/defective water collection.   The water you collect now will be used during the warmer Spring days.

Pruning

Take time to inspect each plant thoroughly, gently removing any yellowing or dead foliage. This pruning serves two important purposes: it prevents the spread of fungal diseases that can thrive in the humid greenhouse environment, and it allows the plant to direct its emerging energy toward new growth rather than maintaining deteriorating leaves. The removal of dead material also improves air circulation around the plant, creating conditions that support robust spring development. Think of it as preparing your plants for their spring awakening – much like how we might clean and organize our living spaces to prepare for a new season.

What to Plant in February:

Early seed starting in February marks a pivotal moment in the gardening calendar, as it initiates a thoughtful strategy for maximising your growing season. For gardeners with access to specialised equipment like heated propagators and grow lamps, this opens up exciting possibilities for starting warmth-demanding vegetables such as chillies, aubergines, and tomatoes. These plants particularly benefit from an early start, as they need a long season to produce their fruits. However, even without such equipment, you can still start your growing journey by utilising a bright windowsill to nurture hardier vegetables. Peas and kale, being more cold-tolerant, will happily germinate in these conditions, giving you a head start on the growing season. Similarly, flowers like sweet peas and cosmos can begin their journey indoors now, developing into robust seedlings ready for spring transplanting.

February also presents an excellent opportunity for establishing larger plants through bare-root planting – a method that offers both economic and horticultural advantages. When you plant trees, shrubs, and perennials like Japanese anemones and hardy geraniums in their dormant, bare-root state, you’re working with nature’s rhythm. As soil temperatures gradually warm, these plants will awaken and establish strong root systems before the demands of spring growth begin. Think of it as giving them time to “settle in” before the busy season starts.

To ensure your garden continues to delight throughout the warmer months, consider planting summer-flowering bulbs such as eucomis and lilies in containers now. These will develop quietly underground during spring, emerging to provide waves of color when many spring-flowering plants have finished their display. This approach to garden planning – thinking several seasons ahead – helps create a garden that remains vibrant and interesting throughout the year.

Vegetables

1. Cauliflower – plant seeds deeply and keep covered until germination. These thrive in modules or seed beds and can be transplanted after six weeks. Ensure proper spacing and firm soil when moving to their final position.
2. Pak Choi – perfect for winter planting, these fast-growing vegetables can be ready to harvest in as little as 50 days. Plant in well-spaced, shallow rows in compost, positioning in a south-facing spot. Regular, consistent watering is key, but avoid water-logging.
3. Carrots – early cultivars can be started now in deep containers (40-50cm). Sow shallowly in rows, maintain consistent moisture during germination, and prepare to thin seedlings as they develop.
4. Other Vegetables –
   • Leeks (no heated propagator needed)
   • Early cabbage varieties
   • Salad leaves and lettuce
   • Broad beans in pots
   • Peas

Flowers

1. Delphiniums – plant approximately 3mm deep in pots or seed trays. Keep soil covered until germination and maintain consistent moisture. Separate seedlings when they develop their second set of leaves.
2. Violas – plant under plastic covering and maintain moisture through spraying. Position in bright locations but avoid direct sunlight. Separate once leaves are fully formed.
3. Additional Flowers:
   • Sweet peas (soak seeds overnight before planting)
   • Lobelia (in heated propagator)
   • Cosmos
   • Petunias
   • Chrysanthemums
   • Geraniums

Expert Tips for Success:

• Maintain vigilant temperature control, especially during nighttime hours
• Position seed trays and pots away from frost-prone areas
• Use horticultural fleece for additional protection on particularly cold nights
• Check soil moisture levels regularly, especially on sunny days
• Ensure proper ventilation on warmer days, while remembering to close up at night
• Install automatic ventilation – see our range of automatic vent openers – The Greenhouse Shop | Spares & Accessories | Elite | Halls | Juliana
• Consider using a heated propagator for tender plants and flowers
• Label all plantings clearly with dates and varieties

Remember that success in February greenhouse gardening largely depends on maintaining stable growing conditions. While this month can be challenging due to temperature fluctuations, the early start will reward you with earlier harvests and blooms as the season progresses.