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Intelligent Heating

Horticultural Soil Warming Frequently Asked Questions

Why do I need soil warming?

One of the keys to a successful garden or greenhouse is to start planting in late winter and early spring. Unfortunately, in many areas, very cold nights and near freezing temperatures still prevail even when the days become warm. You can successfully begin your planting much earlier if you heat the soil to a higher temperature than the surrounding air. This will also increase your seedling propagation and growth rate, allowing your plants to flourish given the proper nutrients and conditions.

According to the Royal Horticultural Society, many plants can benefit from Soil Warming

Soil Warming Cables improve growth

What is the HeatSafe Solution?

The key to correct soil warming is to provide a stable temperature throughout the soil bed. The best way to accomplish this is to use inherently temperature safe self-regulating heating cables buried in a layer of sand or clay under the soil. Because the heating cable self-regulates, you can expect a constant soil temperature over the entire planting area.

complete soil warming system

Our solution is completely customisable, you will receive the proper heating cable, in addition to all connections, terminations and ancillary equipment, pre-wired so that you don’t have to conduct any electrical work. Almost any shape or size of soil bed can be accommodated, such as: greenhouses, cloches, cold frames, or propagation trays. HeatSafe cable can also provide freeze protection in a greenhouse if installed into the floor or around the base of the greenhouse.

Our extensive Solution Designer will guide you through the process one step at a time to ensure you design and receive the correct cables and components for your particular installation.

As always when you choose HeatSafe you will not have to:

  • Worry about choosing individual components and their safety or effectiveness
  • Splice any electrical cable, or conduct any electrical work
  • Hire an electrician or professional installer

What is self-regulating heating cable?

Self-regulating Heating cable is a major technological advancement when compared to resistance wire based heaters (also known as constant wattage). In a self-regulating heating cable, electrical current passes through two bus wires which carry electricity but do not produce heat. A specially designed semi-conductive core containing a mix of carbon and polymer is extruded around the bus wires. Due to the makeup of the core, electrical resistance will change depending on temperature.

  1. At cold temperature, more electrical pathways become available, resistance lowers and more heat is produced.
  2. As the temperature increases, less electrical pathways are available, resistance increases, and less heat is produced
  3. When maximum temperature is reached, no electrical pathways are available and no heat is produced.
HeatSafe inherently temperature safe self-regulating cable cannot overheat or burn out

Why should I buy from HeatSafe?

Self Regulating Heating Cables - Intelligent Design

A conventional heating cable relies on a separate thermostat to switch on and off. Should that thermostat fail, the cable could heat up to the point where it could destroy itself or damage your delicate seedlings and plant roots! All HeatSafe cables are inherently temperature safe. Our Heating Cables have zero output at their maximum temperature.. Thermostatic control provides additional energy efficiency and automatic operation; it is not used as a safety feature.

This technology is what sets us apart from other manufacturers. Some will market their cable as self-regulating, but then the installation instructions will warn you not to cross or overlap the heating elements. This is not safe; they are using their thermostat as a safety feature. Cheap heating cables can overheat and lead to the risk of fire.

HeatSafe cable meets the requirements of the world standard IEC62395 for trace heating in commercial applications. As required by the standard, HeatSafe is provided with an earthing facility and leakage protection which is missing from many competitor devices and can pose a significant safety risk!

Our unique system of IP68 certified dust and water tight, connections and end seals provides the HeatSafe solution with additional advantages:

  • Use a quality screw down protective cover to ensure easy and safe connection.
  • Each system is designed to your specifications, and in many cases can be upgraded or added to at a later date.

Where can I use a HeatSafe Soil Warming System?

Because our system is bespoke to your particular needs, we can accommodate a variety of installations, including:

  • Greenhouse Floors and Tables
  • Propagation Trays and Benches
  • Cloches
  • Cold Frames
  • Outdoor soil beds
  • Almost any other sized or shaped medium!

What is the Optimal Soil Temperature for my plants?

Optimal Soil temperature for seed germination and plant growth depends on type of plants grown. The use of electric soil warming allows earlier planting, improved growth times and healthier plants. Please consult the chart below for more information.

Soil Temperatures for Seed Germination and Plant Growth

Plant or Crop TypeTemp (°C)Temp (°F)
Asparagus 24 75
Bean 26.5 80
Bean, Lima 30 85
Beet 30 85
Cabbage 30 85
Carrot 26.5 80
Cauliflower 26.5 80
Celery 21 70
Chard, Swiss 30 85
Corn 35 95
Cucumber 35 95
Eggplant (Aubergine) 30 85
Lettuce 24 75
Muskmelon 32 90
Okra 35 95
Onion 24 75
Parsley 24 75
Parsnip 18 65
Pea 24 75
Pepper 30 85
Pumpkin 32 90
Radish 30 85
Spinach 21 70
Squash 35 95
Tomato 30 85
Turnip 30 85
Watermelon 35 95

Is it expensive to run?

The cost of running the soil heating system will depend on several factors including the soil bed area,  temperature, moisture content and composition. Proper use of an Adjustable Thermostat will provide increased energy efficiency by deactivating the circuit when the desired temperature is reached.

Can I install it myself?

Yes! No electrical work or experience is required other than plugging the system into a power outlet and connecting the “click and secure” modular components. Our Installation Guide provides detailed and easy to follow instructions.

Most manufacturers provide you only with heating cable cut to specific lengths and leave the rest up to you. This can lead to incorrect installation, shorter product life, and a less functional and efficient solution. Our Solution Designer will assist you in creating your entire soil warming system to your requirements. Contact Us for any additional installation or general questions.

Can HeatSafe cable be cut and joined?

HeatSafe self-regulating heating cable is of a parallel resistance type and, as such, is capable of being cut-to-length, spliced, or joined. But, such work should only be undertaken by an electrician qualified for such work.

It is intended that your HeatSafe system is bespoke to your specific needs, so that electrically, it requires nothing more than plugging into your electrical supply socket. Our system is also designed to be modular so that it is flexible enough not to require splicing.

What components make up a complete solution?

HeatSafe Solution Designer

HeatSafe Logo

Our unique Solution Designer provides you with all the elements required for your Soil Warming project.

It is easy to use! You answer a few basic questions about your location and needs. All required calculations and product selection is done by the designer.

You will be provided a complete solution in a matter of minutes. All items are placed into your cart, and checkout is only a few clicks away.

Self-Regulating Heating Cable

HeatSafe Self-Regulating heating cable for horticulural soil warming

The appropriate type and length of HeatSafe inherently temperature safe self-regulating heating cable, . They are designed to provide the correct amount of heat for your plants and soil conditions.

Because they are self-regulate along their entire length, they provide more heat where it is needed, and less where it is not, creating an optimal environment for plant growth.

Cold (Power) Lead and RCD Assembly

RCD Ground Fault Circuit Protection is standard on all HeatSafe products

Lead connecting the power supply with the heating cable. The default length is 2 metres with an extension length as required. The supply plug will be customised for your location: UK, EU, Asia or North America.

An RCD is integrated into the power extension lead. Also known as a Ground Fault Circuit Interrupter (GFCI), this safety feature provides electrical protection and reduces the possibility of fire or injury though electric shock. It is designed to de-activate the Heating Circuit if the cable should become damaged and an earth leakage is present.

Adjustable Thermostat (AT-A)

Adjustable Thermostat

The optional adjustable soil thermostat (AT-A) will monitor the temperature of the soil bed and apply heat as required to maintain the appropriate temperature for your plants or seedlings. This improves energy efficiency and provides automatic operation.

The Adjustable Thermostat Box also provides 16A power distribution up to 250V. The power extension lead Plug fits into the POWER IN socket on the side of the box. The HEATING CABLE socket fits into the HEATER OUT plug of the box.

The Soil Temperature Probe is an armoured capillary thermostat which can be extended up to 1.2m from the box to provide accurate soil temperature readings. It should always be placed 25-50mm (1-2") into the soil and at least 50mm (2") from the heating cable

The front panel of the Adjustable Thermostat may be opened only if the entire system is disconnected from the power supply. This is done to allow access to adjust the thermostat setting. Ensure that the box cover is fully closed before reconnecting the system to the power supply.

What if I don’t understand or I need other help!

Contact Us for more detailed information

We understand that the selection of systems and cables online is huge and you can be presented with a plethora of choices and options, which can be overwhelming. We are always available to help you! If you need more information about any of our product, or website, please let us know. We have experts on hand at all times.

Please Contact Us, All e-mails will be answered as soon as possible, we aim to provide you with excellent service and information.