Cold Frames

Cold Frames

Cold frames are a practical solution for gardeners looking to extend their growing season and protect plants from unpredictable UK weather.

They create a controlled microclimate, shielding plants from frost, wind, and rain while allowing sunlight to nourish them. Cold frames enable you to start seedlings earlier in spring and continue harvesting into autumn.

At Posh, we offer a range of cold frames in various sizes, styles, and price points. Our cold frames buying guide will help you find the perfect option for your garden and budget.

What Are Cold Frames and Why Use Them?

Definition of Cold Frames

Cold frames are simple structures that trap sunlight and retain heat, creating a warm microclimate. Typically made with an open-bottomed box and a transparent top, such as glass or plastic, they are ideal for season extension and frost protection, enabling plants to flourish in cooler weather.

Benefits of Using Cold Frames

Cold frames extend the growing season, allowing for earlier planting in spring and longer harvests into autumn. They create a beneficial microclimate for early seed germination and help harden off seedlings that have started indoors or in a greenhouse.

Cold frames protect plants from frost, wind, rain, and pests, making them ideal for growing hardy winter crops like leafy greens. They work well in raised beds or garden beds and can be used with a multi-cloche to cover multiple plants.

Ideal Crops for Cold Frames

Cold frames are perfect for growing cool-season crops such as spinach, lettuce, kale, and radishes. They provide protection for more delicate crops in raised beds or garden beds, extending the growing season for cool-weather vegetables and enabling harvests throughout winter.

Cold Frames vs Mini Greenhouses

Both cold frames and mini greenhouses help extend your growing season, but each offers distinct advantages. A cold frame creates a ground-level microclimate for seed germination, frost protection, and hardening off seedlings.

A mini greenhouse, with its added height, offers a more controlled environment and better protection to grow taller plants in harsher weather. Cold frames are more portable and cost-effective, while mini greenhouses provide year-round coverage.

Types of Cold Frames

Good: Basic DIY Cold Frame

A basic DIY cold frame can be built using straw bales or recycled materials, with a repurposed window or plastic sheet for the top. Ideal for budget-conscious or beginner gardeners, it provides basic weather resistance and frost protection, making it a simple and affordable solution.

Better: Wooden Cold Frame

A wooden cold frame made from untreated wood and topped with polycarbonate or similar materials offers improved insulation and durability.

Manual ventilation can be managed with tools like shovels. This design is more robust and suited to gardeners seeking a sturdier, longer-lasting option.

Best: Advanced Cold Frame with Automatic Ventilation

The most advanced option uses cedar planks with acrylic tops and features automatic ventilation through heat-sensitive hydraulic risers for precise temperature control. Requiring minimal intervention, it’s ideal for gardeners looking for reliable, long-term season extension with little effort.

What to Consider When Buying a Cold Frame

Size and Space Requirements

Consider how many plants you’ll be growing—whether you’re starting seedlings or protecting mature plants. Assess the size, dimensions, and layout of your garden bed to ensure the cold frame fits without overcrowding.

Location and Climate

Position your cold frame facing south to maximise sunlight. Keep it sheltered from strong winds, or use insulating materials like straw bales for added protection. Ensure it’s built for weather resistance, especially in harsher climates.

Material and Durability

Cold frames can be made from wood, plastic, or metal. Choose covers like polycarbonate, acrylic, or glass for durability and light transmission. Consider recycled materials for an environmentally friendly choice.

Portability and Permanence

If flexibility is key, choose a lightweight, portable cold frame. For larger gardens with fixed raised beds, a permanent structure provides long-term protection and stability.

Accessories to Enhance Cold Frame Use

To get the most out of your cold frame, consider adding these accessories for increased strength, durability, and functionality:

• Rafter Kits: Provide extra strength, particularly in snowy climates, reinforcing the sturdy walls and ensuring stability during harsh weather.
• End Frame Kits: Increase durability and allow for features such as roll-up doors, improving weather resistance and making the frame more accessible.
• Recycled Plastic Lumber: Ideal for building raised beds within cold frames. It’s durable, eco-friendly, and resistant to various weather conditions, offering improved soil conditions for all the plants.

Why Choose Posh for Your Cold Frames

Posh offers a premium shopping experience, ensuring you get the best value and support when choosing your cold frames:

• Free Delivery on most items and all orders over £500, plus an Express Service for next-day delivery.
• Best Price Guarantee—if you find it cheaper elsewhere, we’ll beat the price.
• Trusted by thousands of customers, we offer a 100% money-back guarantee and a comprehensive returns policy.

Benefit from expert advice and aftercare from the UK's leading team, with flexible payment options like PayPal Pay in 3 or Klarna.