Soil Warming / Heating Cables
Early propagation requires a consistent soil temperature of 12ºC to 16ºC. Germination and root development are very slow below these temperature levels. With our range of flexible silicone covered electric SOIL WARMING CABLES it is easy to build a simple effective propagator.
The cables are ready to use and can be plugged into a thermostat for complete temperature control. CE approved, made in Europe
Cable lengths available:
6m long - 50watts- covers 0.8 - 1.0m²
10m long - 100watts - covers 1.6 - 2.0m²
25m long - 320watts - covers 3.0 - 4.0m²
Instruction for making a Propagation Box with Heating Cable
The size of the box depend on the length of the cable. The following dimensions are recommended:
HK6 – 6m cable length - 50 watts 0.8m2 – 1.0 m2
HK10 - 10m cable length – 100 watts 1.6m2 – 2.0 m2
HK25 - 25m cable length – 320 watts 3.0m2 – 4.0 m2
The width/length of the box should be defined to take the maximum number of propagation trays.
Material required: Plywood 18mm ( e.g. 1 or 2 sheets 244cm x 122cm) , chipboard screws 4x40,
Aeroboard 15mm to 25mm (or similar), strong plastic sheet to line the box,1 wheelbarrow of dry, course, washed sand.
Location of box: In a tunnel or greenhouse or in an outbuilding (daylight required)
Position of box: The box can be put on blocs on the ground or on a bench or table.
Construction: Cut out plywood for base according to the required dimensions. The sides of the box should have a min. height of 30cm but could be as high as 60cm. Screw base and sides together. Place aeroboard on the bottom of the box. Glue/nail aeroboard pieces on the sides of the box. (Protection against heat losses). Now line the box with tunnel plastic or similar strong plastic. This protects the timber from the moisture of the sand. Put box in its final location.
Filling: Fill a 2.5cm (1”) thick layer of dry sand into the box and level it . Drill a hole into the wall of the box nearest to a socket. The hole should be big enough to feed the heating cable through. Stick the complete cable from outside through the hole. Now run the cable over the sand in such way that it is evenly distributed over the whole area. (The cable could be plugged in immediately before this to make it soft and pliable). Fill another 1 – 1.5cm of sand over the cable or as much is needed to cover the cable. It should not be buried too deep. Level the sand carefully to achieve a smooth surface. The cable can now be plugged in. The heat will be distributed through the sand.
When the propagator is in use keep the sand always moist (NOT WET)
Thermostat- To avoid overheating (e.g. additional heat due to sunshine) and electricity waste, a thermostat can be used to regulate the temperature.
To fit the plug of the heating cable into the Thermostat unplug the heating cable, loosen Philips screw from black plug cover. Now pull out the ‘Euro 2 pin plug’ which is hidden under the 3pin plug cover. Plug the 2 pin plug into the bottom of the Thermostat. Fix Thermostat at/near propagation box. Stick stainless steel tip of sensor into the soil of one propagation tray. Now you are ready to control the heating cable via the Thermostat . Set Thermostat according to the manufacturers instructions.
Tip: It is highly recommended to install a light source directly over the propagation box. Often propagation takes place in short days where there are not enough natural light hours to achieve healthy plant growth. With the help of a light tube (ideally ‘Grow Light’ tubes or similar lights for plant growth) and a plug-in timer the plants can be exposed to additional light hours. This will reduce the danger of ‘legginess’.
In order to protect the plants in the propagator from night frost lids could be made up. Make several frames from 1”x 1 ½” (or similar) timber – large enough to cover the box. Staple bubble film onto the frames. This leaves some light through but reduces the danger of frost damage.