How to make and manage a traditional hot bed

A hot bed is a great way to get a head start on the gardening season. By using the sun’s warmth to heat up the soil, you can create an environment that is ideal for starting seedlings and growing plants. And best of all, it’s easy to make your own hot bed.

First, choose a sunny spot in your garden and clear away any debris. Then, build a frame out of wooden boards or bricks.

To make a hot bed construct a frame similar to that recommended in “The Cold Frame.” The hot bed varies from the Cold Frame as the latter is at the ruling temperature, whilst the ”Hot Bed,” as its name implies, derives heat from its constituency.

It should be sheltered from Southerly and Westerly winds, and fully exposed to the sun. Select a perfectly dry position and one easily accessible and well drained, as if water is permitted to lie about the base of the bed, a good, even temperature cannot long be maintained.

Before planting, check the temperature of the soil using a thermometer. The ideal temperature for most plants is between 70 and 80 degrees Fahrenheit. When the soil is at the right temperature, simply remove the covering and start planting your seeds or seedlings. With a little care and attention, your hot bed will provide a perfect environment for all your plants to thrive.

Line the frame with black plastic, making sure that there are no gaps or holes. Next, fill the frame with a mixture of manure compost and sand. The compost will help to retain heat, while the sand will promote drainage. Whilst the bed of the Cold Frame consists of good potting soil, the Hot Bed is made of fresh stable manure, including the long litter. Build this up in a heap close to where the Hot Bed is to be made, and turn it every few days, or whenever the heat becomes too intense. If too dry, water until the mass cools down a little, so as to ensure a steady and continuous warmth.

Dig a pit about 18 to 24 inches deep on the site intended for the bed. When this is ready spread the manure evenly in the bed of the frame, allowing it to overlap the sides and ends of the frame by about a foot or eighteen inches.

The sides and ends of the bed should be perpendicular, and the whole, as the work proceeds, must be well trodden after being firmly beaten down by the back of the fork, so that the material will be of a uniform density. When finished, the bed should be about two feet deep. The deeper it is, the steadier and more continuous will be the heat, provided that, in the first place, the material has been well put together. Finish the bed evenly on the surface and then set the frame on and cover it with the glass sashes.

At first a strong heat will arise but when this has somewhat abated, so that the temperature is down to 85 or 90 degrees F, spread a layer of soil six inches in depth, evenly over the bed inside the frame. The temperature should always be tested with a thermometer and never guessed at.                    

The Hot Bed is now ready for use, and seeds may be sown in boxes or pans and placed inside.

In the management of a Hot Bed, ventilation must be given careful attention in order to regulate the temperature, which must not be allowed to become too high. This is particularly essential when the seeds have germinated, as if the seedlings are subjected to a high temperature and humid atmosphere, they will grow spindly, and will not be strong and sturdy for transplanting when large enough to handle.

As soon as the seedlings have made their first leaves, admit air freely during the warmer part of the day, but care must be taken to prevent draughts. The object in view is to grow sturdy, vigorous plants, and this end can only be achieved by careful and efficient ventilation. Water sparingly, but never allow the seedlings to become dry, and if necessary, shade should be given to the young plants for an hour or so during the middle of bright, sunny days. When the seedlings are from one and a half to two and a half inches high, gradually accustom them to the outdoor temperature.

Where a cold frame is available this presents a simple and effective method of hardening the young plants before they are planted in their permanent position in the open garden.