The Content Of The Article:
- Advantages of a cold frame
- Cold Frame models
- Kit or homemade?
- Materials and dimensions
- The optimal location
- Natural heating for the cold frame
Advantages of a cold frame
With a cold frame, the garden season lasts almost 365 days. It can be used in early spring for preculture of various types of vegetables, but is also suitable for the permanent culture of fruits and vegetables and brings even in winter yields - but it can be grown, for example, winter salads. In addition, the miniature greenhouses are usually very easy to manufacture, cost and also find in smaller gardens space. Depending on the model, they can easily be moved or dismantled and temporarily stowed away.
Cold Frame models
Which model you ultimately choose depends on what you want to use the cold frame for and how much space you have in your garden. A box made of wood has the advantage that it can easily be removed after the growing season and stored in the dry shed until next spring. Although massive cold frames, for example of clinker brickwork, last much longer, their location needs to be well considered. They can not be put off easily. If you want, you can equip the lid with an automatic window regulator, as it is known from greenhouse windows. The liquid inside the pressure cylinder expands at higher temperatures, opening the cover so that fresh air can flow in.
With a cold frame you can achieve rich harvests
Kit or homemade?
Kits, from which a cold frame can be built up in no time, are now offered so cheaply that the former customary designs are less and less to be found. However, if you prefer a stable cold frame made from a sturdy wooden frame, because it is less intrusive, for example, in the garden, you can build it yourself.
The simplest variant consists of a flat wooden frame, which is bevelled down to one of the two longer sides. This page aligns the cold frame when setting up south. As a cover also serves a wooden frame. It is covered with sturdy, transparent foil and fixed with hinges to the rear, higher wooden wall. A bit more expensive is a lid made of polycarbonate multi-wall sheets. The purchase is still worthwhile because it is much more robust and better insulated against the cold. As with the greenhouse, although the long-wave heat radiation can penetrate into the cold frame, the heat radiated from the earth is held purely by the cover in the cold frame.
Thanks to the beveled roof, this self-made cold frame makes it easy to set up the windows and ensure good ventilation
Materials and dimensions
For a standard cold frame is at least 20 mm thick spruce wood very well. Better yet is decay-resistant wood such as larch, oak or Douglas fir. In any case, it should be treated in advance with a plant-compatible wood preservative. Depending on the intended use, the height of the wooden frame should be at least 35 centimeters at the front and 50 centimeters at the rear. If the cold frame is not only used for young plant cultivation, the frame can be even higher. The oblique shape allows better utilization of light. The depth of the cold frame should not exceed one meter so that you can approach the rear plants from the front. The length can be chosen individually. A length of 1.5 to 2 meters offers at least 1.5 to 2 square meters of acreage. That's enough for the first salads and radishes.
Instead of glass (risk of breakage!) Better double-skin sheets should be used for the cover. A cheap alternative is greenhouse film. Recommended is the already mentioned automatic, de-energized vent opener; depending on the temperature, it opens and closes the cover automatically. Otherwise, in the sun, the cover must be raised by hand in time.
The optimal location
Cold frames basically work like miniature greenhouses. The heat is generated either by a natural heater (see below) or by the captured light. Cold frames should always be in a sunny place in the garden. This means they can fully exploit the still weak light at the beginning of the gardening season and benefit from the natural sunlight even in winter.
Natural heating for the cold frame
Natural heating: The correct filling heats the cold frame
If you want to sow especially early, you can equip your cold frame with natural heating. For this purpose, the soil in the bed is dug about 40 centimeters deep and then filled in a about 20 centimeters high layer of horse manure. If it is pure horse manure without stable litter, it should first be mixed in a ratio of about 1: 1 with straw or leaves.This layer is covered with an equally 20 centimeter high layer of garden soil, which was previously enriched with some potting soil or compost. The microorganisms begin immediately with the decomposition of the nitrogen-rich horse manure, developing carbon dioxide and heat. Both penetrate through the upper soil layer and offer the seeded young plants optimal conditions for germination and growth - even if there is still snow outside. It takes about a week for the upper layer of soil to warm up after filling with horse manure - then you can start sowing.
In the spring, the harvest of lettuce, radishes and kohlrabi can be brought forward by a good three weeks with a cold frame
Depending on the region and the weather, the garden season starts with a cold frame already in February, but at the latest in March. Here grows the first spring vegetables, at least four weeks earlier than in the field. Salads, spinach, kohlrabi, radishes and herbs are the preferred ingredients. In addition, frost-sensitive young plants can be brought forward, and then later planted in the vegetable or in the flowerbed. In summer, the hotbed can be used for the culture of peppers, aubergines, cucumbers or melons. In winter, it grows among other field and endive salad. Many garden owners use their cold frame also for vegetable species with a long culture period, which are piqued again after sowing and transferred to the garden bed. These include, for example, salads, tomatoes, cucumbers and all kinds of cabbage.
Our tip: You can sow your vegetable or flower seeds even in the cold frame in multi-pot plates or individual pots. When you lower them into the ground, the soil is heated by the rotting process in the ground. When the cold frame is free again after potting the young plants, you can use it for new sowing or short crops such as radishes, lamb's lettuce or spinach.