For those seeking plant protection in colder months without the space or budget for a greenhouse, cold frames or cloches serve as excellent alternatives, especially in small gardens.
A cold frame essentially functions as a mini greenhouse, offering various benefits for gardeners, particularly beginners. Portable and well-suited for small spaces, cold frames provide an efficient means to extend growing space, especially when traditional greenhouses are already at full capacity.
On the other hand, a cloche, derived from the French word for ‘bell’, performs a similar function but on a smaller scale. Placed over individual plants, cloches act as protective covers, shielding them from cold temperatures. These versatile structures offer practical solutions for plant care and growth during the colder months, providing flexibility and adaptability to various garden sizes and layouts.
WHAT IS A COLD FRAME?
Katie Burdett, an organic gardener and greenhouse expert, describes a cold frame as a tool employed in gardens and farms to extend the growing season during cold weather. Additionally, it serves the purpose of starting and/or hardening off seedlings. Drawing parallels to a mini greenhouse, cold frames can be constructed entirely from polycarbonate plastic or crafted at home using a wooden frame and an old window, according to Katie.
Unlike a greenhouse that requires heating, a cold frame operates without such a need. To help you get started with this versatile gardening tool, here are five ideas to explore.
1. Raised Off The Ground: 
Opting for a raised cold frame proves beneficial for those seeking to protect their back while attending to seedlings. This design offers easily accessible growing space at a comfortable height, eliminating the need for constant bending. Raised cold frames typically feature a hinged lid and sides made of glass or plexiglass, allowing light in while keeping cold and rain out. Look for designs with a shelf underneath for additional storage.
2. Split Lid Solutions: 
Cold frames with two independently opening lids provide versatility by allowing extra light and air into one side without affecting seedlings or plants on the other. Opting for a lid with two height settings adds practicality. Ensure the cold frame is pressure treated to resist rot, especially if placed directly on the ground, ensuring longevity.
3. Lightweight For Maximum Flexibility: 
For those considering moving the cold frame to different positions in the garden, selecting a lightweight material like aluminum is a wise choice. Designs made from aluminum, along with polycarbonate panels instead of glass, enhance mobility. Choosing a hinged lid, even if it comes at a slightly higher cost, is advisable for easy plant access, as juggling the lid and handling plants with one hand can prove challenging.
4. Smaller Structures For Salad: 
Salads thrive in greenhouses, but for a more compact solution, consider a salad cloche. Tailored for growing herbs, lettuce, and salads, some come with their own raised bed for placement on a balcony or outside the back door. These cleverly designed cloches feature convection ventilation, allowing warm air circulation. During the summer, you can remove the side glass to create a sun trap or enable rain to water your salad crops.
5. Individual Plant Protectors: 
The classic domed cloche, originally used to shield individual seedlings and young plants from light frosts, cold winds, and pests like birds, slugs, and squirrels, remains a valuable option. Available in toughened plastic, glass, or bamboo, these cloches come in various sizes suitable for different stages of plant growth. A useful tip is to line them with fleece or straw to warm up the soil on chilly mornings, ensuring optimal conditions for your plants.
FAQS
WHAT PLANTS CAN BE GROWN IN A COLD FRAME?
According to Katie Burdett, an organic gardener and greenhouse expert, the optimal plants for cultivation in a cold frame are those that are low-growing and cold-tolerant. Ideal candidates include lettuces, spinach, cilantro, dill, parsley, mache, and mustards. Additionally, cold frames serve as a temporary shelter for hardening off seedlings, providing a transitional environment before they are fully exposed to external conditions.
WHAT MATERIALS CAN BE USED FOR A COLD FRAME?
Katie Burdett, an organic gardener and greenhouse expert, highlights that a cold frame constructed entirely from polycarbonate plastic offers advantages such as better light diffusion and reduced weight. On the other hand, a cold frame made from wood and glass tends to be heavier and permits less light penetration. Regardless of the chosen material, Burdett emphasizes the importance of providing ventilation on sunny days, even in colder weather. Planning for an automatic opener or being available to prop it open is essential for maintaining the optimal conditions inside the cold frame.
