Gardeners are always keen to get growing as early in the year as possible, but with low light levels and cold temperatures as well as sudden frosts lasting well into spring, success is not guaranteed. The answer is a heated propagator - a unit that allows you to start your vegetable and flower seeds off under cover with a consistent temperature throughout the day and night. This ensures a much higher rate of success, and earlier results.
Read about our recommended seed suppliers.
Heated propagators are perfect for gardeners who don't have access to a mini greenhouse, greenhouse or polytunnel, as many units are made to be used on your windowsill, meaning no matter what size your home and garden, you can enjoy sowing and growing a range of blooms and produce without having to wait until April or May, when outside temperatures are warmer. They can also protect against cold snaps and very low temperatures at night, which are possible right up until late spring.
Find out everything you need to know about planting seeds
Heated propagators are ideal for tomatoes, chillies and peppers that need plenty of time in which to germinate, grow and produce ripe fruit. Sowing them in a heated propagator early in the season guarantees that they will get the long growing season they need.
Heated propagators can be the perfect place to encourage cuttings to root, too, thanks to their bottom heat and humidity.
Heated options do – of course – cost more than non-heated options and will need to be close to a plug socket. While a heated propagator can be an investment, it will repay you quickly - it is much cheaper to grow plants from seed than it is to buy plants.
How to choose a heated propagator
There are several things to consider when buying a heated propagator, including:
Size - many heated propagators fit neatly on to a windowsill. Some heated propagators have taller lids, which are better for starting off cuttings.
Cable length - check that the cable is long enough for you to easily plug in the propagator.
Separate compartments - these are deal for raising a selection of seeds and cuttings at the same time, as each section acts as an isolated unit.
Air vents - most heated propagators have air vents hat allow you some control over the internal temperature (allowing condensation to dissipate).
Watering options - a tray at the base means that watering is easier. Some have capillary matting so that plants can take up water as they need it.
Lights - some heated propagators have grow lights to further aid growth.
The best heated propagators to buy
Suttons Super 7 Electric Propagator
If you’re new to the world of propagating plants and perhaps don’t have an outdoor space available then this all-in-one option from Suttons really has all you need to get growing. It’s tailor-made for a windowsill, allowing you to turn a bright spot into your own indoor grow zone.
There are seven separate compartments, minimising the volume of air circulating and keeping each compartment cosy and warm, and adjustable vents on every section allow you to cut down on condensation and release a little heat should it be required. It also means that you can sow a different type of seed in each section. A simple 13w heating element in the base provides consistent even heat across all the units.
Dimensions: 18.5cm x 76cm
Selections Jumbo Windowsill Heated Plant Propagator
If you’re sowing en masse and don’t require separate compartments then this simple all-in-one unit is perfect. It’s large and lengthy at 80cm but at just 20cm deep still thin enough to place on a windowsill.
Either fill the 5cm deep base with pots or fill directly with your chosen compost and sow with impunity! Vents in the lid prevent condensation – head-height is 12cm here – and a thermostatically controlled 12w heating element will maintain a constant 21 degrees centigrade.
Dimensions: 20cm x 80cm
Stewart Thermostatic Heat and Grow Electric Propagator
This premium electric propagator goes the extra mile, giving your growing more room to breathe and comes complete with a set of trays and 10 pots to cater to plants and flowers of any size. Its 22w heater has the capacity to quickly heat up and maintain temperature within the main space and the thermostat control allows you to dial in a heat of between 18 and 23 degrees then let the unit keep that constant without further intervention. Of course, vents on the top allow you to release hot air and moisture should it be required.
28cm height gives headroom for your cuttings while 52cm width and 45cm depth make it perfect for a sunny kitchen worktop, table or bench.
Dimensions: 45cm x 52cm
Big 3 Electric Propagator
This large heated propagator has three large vented propagating trays offering a huge propagating area. Each section of the propagator comes with vented lids for individual control. It's ideal for raising a selection of seeds and cuttings at the same time.
Dimensions: 80.5cm x 41cm
EarlyGrow MPL50034/C/P Heated Electric Shatter Resistant 3-Bay Windowsill Propagator with Capillary Mat and Tray
This windowsill propagator is divided into three compartments, each with a shatter-resistant lid and air vent. The base of the seed trays have holes, so you can easily water your seedlings via the tray beneath.
Dimensions: 21.5 x 54.5 cm
Sankey Growarm 100 8w Electric Heated Plant Seed Propagator Kit
This heated propagator includes two 21cm seed trays complete with capillary matting. With its clear rigid lid and adjustable ventilation, you can easily control both humidity and temperature. The 8w heated base maintains a gentle heat.
Dimensions: 38cm x 24cm
Riogoo Seedling Heat Mat and Thermostat
These mats are popular with professional nurserypeople and gardeners who have growing tables in their polytunnel or glasshouse. Lay the mat and place your pots and trays of seedlings and cuttings on top, then set the thermostat and let it deliver gentle warmth exactly where it’s required.
The 24cm by 52cm mat is 100% IP76 waterproof so you can water your plants exactly as normal, and has a scuff resistant coating so it can take more than a few knocks. The digital thermostat lets you set a precise temperature and a separate wired soil probe measures the temperature in your pots meaning whatever you set will be maintained with 100% accuracy.
Dimensions: 24cm by 52cm
Why not take a look at our favourite seedling trays to use with your heated propagators? Our list includes peat free fibre pots, bamboo trays and reusable rubber options, so you don't have to rely on plastic designs.