How Early Can I Start Growing in a Greenhouse?

As the seasons change, so does the anticipation of cultivating plants in a greenhouse. In this blog, we delve into the exciting question: “How early can I start growing in a greenhouse this year?” Read on to uncover the secrets of optimal timing. We’ll also explore the factors to consider in extending your growing season. Keep reading!

Understanding Your Growing Zone

Knowing about growing zones is key to successful gardening. They categorise regions based on climate conditions. This allows gardeners to choose plants that thrive in their specific locale. The UK’s growing zones range from Zone 7 in the milder southern regions to Zone 8 in the warmer southwest. These zones provide a crucial framework for gauging plant hardiness and stability.

For instance, plants thriving in Zone 7 might face challenges in the cooler conditions of Zone 5. To determine your zone, consult the UK Hardiness Zone Map. Or you may use online resources tailored to your specific location. The Royal Horticultural Society (RHS), for one, offers zone-specific information.

Armed with this knowledge, you can make informed choices about when and what to plant. This, in turn, ensures a flourishing garden that thrives well in your local climate.

Ideal Early Months for Garden Greenhouse Growing

BillyOh Switch Apex Wooden Greenhouse
BillyOh Switch Apex Wooden Greenhouse

Timing is everything in greenhouse gardening. Understanding the best months for your growing zones is the first step to a bountiful harvest. In the UK, Zone 8 in the warmer southwest allows for an early start in late winter, typically February. For Zone 7 in the milder southern regions, March heralds the beginning of the greenhouse season. Moving north to Zone 6, April marks the commencement of spring planting.

Spring offers a balanced start for most zones. The temperatures gradually rise, and sunlight becomes more abundant. Late winter provides a head start, advantageous for early harvesting. However, it also poses challenges like unpredictable weather. On the flip side, early summer starts in June and presents warmer conditions. Yet, the risk of overheating and increased pest activity arises.

Choosing the right window aligns your greenhouse activities with nature’s rhythm. This optimises conditions for a successful and fulfilling growing experience.

Factors to Consider Before Starting Early

Plants inside a greenhouse.

(Image Credit: Pexels)

Temperature plays a pivotal role in crop success. Different crops thrive within specific temperature ranges. For example, tomatoes and peppers favour daytime temperatures between 70-85°F. Meanwhile, lettuce prefers cooler conditions around 60-70°F. Be mindful of both minimum and maximum temperature requirements for optimal growth.

Sunlight is a lifeline for plants, but some may need extra illumination. Consider crops like herbs and leafy greens that benefit from at least 6 hours of sunlight daily. In low-light situations, supplement with LED or fluorescent grow lights for robust growth.

Prepare your soil thoughtfully for early cultivation. Early in the season, focus on improving drainage and warming the soil. Incorporate organic matter to enhance fertility and structure. Doing so can help set the groundwork for healthy and thriving plants.

Choosing the Right Crops for Early Greenhouse Growing

A tunnel greenhouse growing spinach.

(Image Credit: Wikimedia Commons)

For early greenhouse cultivation, consider kickstarting your garden with cold-hardy crops like:

  • Spinach
  • Kale
  • Radishes

These vegetables not only endure cooler temperatures but also provide an early harvest. Planting them enables you to jumpstart your growing season. Early cultivation of peas and carrots also ensures a flavourful yield. These greens benefit the controlled environment within a wooden greenhouse.

Growing these crops early comes with distinct advantages. Spinach and kale thrive in cooler conditions, offering nutrient-dense greens before warmer months. Radishes and carrots, when sown early, produce crisp and sweet roots. Peas, with their quick maturity, contribute to an early harvest.

To optimise greenhouse productivity, practice crop rotation annually. This minimises soil-borne diseases and maintains soil fertility. Plan strategically to ensure a continuous harvest. Plant at different times to have a continuous harvest of fresh produce in all seasons.

Tips for Extending the Growing Season

Cold frames are versatile tools that capture and retain heat. They prove invaluable in transitioning delicate seedlings from indoor to outdoor conditions. Similarly, row covers act as shields. They work by safeguarding plants from frost while permitting sunlight penetration. Consider employing cloches and protective domes that shelter plants, further elongating the growing period.

To enhance insulation, insulate the greenhouse with bubble wrap or thermal blankets. Such an addition helps prevent warmth during chilly nights. Strategically positioning water barrels inside captures and releases heat, maintaining an optimal temperature. Boost plant warmth by situating heat-loving plants close to the greenhouse’s warmest areas. Lastly, stay attuned to weather forecasts, covering plants during unexpected cold snaps.

Mastering these techniques ensures a prolonged growing season. They allow you to maximise your wooden growhouse’s potential for a rich and diverse harvest.


To succeed in early greenhouse gardening, match planting times with your zone and grasp each season’s needs. Pick the right crops and use season-extending methods. Additionally, consider temperature, light, and soil prep. Adapt to nature’s rhythm for a thriving garden. Happy gardening!

Explore Garden Buildings Direct today for our range of greenhouses for sale. Top tip: Enhance your gardening experience by integrating a potting shed. It serves as a dedicated spaces for gardening tasks. They offer convenient storage for tools, pots, and other planting essentials.

Up next on your reading list: How a Greenhouse Can Help Your Garden this Autumn