3 Best Heated Electric Propagators to Promote Early Germination! (2021 Review)

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In this guide we’ll take a look at the best heated electric propagators for the UK market.
I’ve compared design, size, energy efficiency and cost
to give you my top recommendations.

What is the Best Heated Electric Propagator?

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Comparing The Best Heated Electric Propagators

Use the dropdown to sort the table by the feature that's most important to you.

  • Best For
  • Seed Capacity
  • Number of 'Cells'
  • Power
  • Adjustable Ventilation
  • Cost
  • Our score

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In-Depth Reviews of Our Recommended Heated Electric Propagators

Garland Super 7 Electric Heated Windowsill PropagatorGarland Super 7 Electric Heated Windowsill Propagator

Best heated propagator

Ease of Use
Value for Money

Garland Super 7 Electric Heated Windowsill Propagator Review


  • Seed Capacity: up to 84 seeds
  • Number of 'Cells': 7
  • Power: 13 W
  • Adjustable Ventilation: No

Propagators can take up a fair amount of room, which is difficult if you perhaps don’t have a greenhouse or conservatory. The alternative is sometimes to use the kitchen worktop, but it’s obviously not ideal.

The 13 W Garland Super 7 Electric Heated Windowsill Propagator measures just 76 x 18.5 x 15 cm and fits onto a window ledge, making it a really practical propagator to have around, especially if you’re a bit short on space.

It’s certainly very effective, prompting seeds to germinate often in a matter of days, or maybe a week at most, encouraging germination in a wide range of plants from tomatoes, to chillies, to flowers like achillea.

Even in colder months like February, it’s possible to kick start growth of lettuce seeds and peas in just a matter of days.

There are seven separate ‘cells’ in total, so you can plant different types of seeds in each one if you wish, and each cell has its own vent to control the temperature according to the different plant.

The roof is high enough to allow seedlings to grow to around 5 cm, and the trays are also sufficiently deep to offer enough space for roots to fully develop. As a result, when it comes to planting seedlings out, they are already well established.

Whilst this propagator does heat well, there is no thermostat nor temperature control; however, it seems to work effectively without the need for either of these features. In general, the temperature inside the propagator rises by around 8°C and maintains a consistent heat.

Depending on where you want to plug this propagator in, the ~2 m power cord might be a little short – using it with an extension cable may be necessary to reach from the windowsill to the plug. Also, it’s not recommended to water the seeds in situ (given that water and electricity don’t mix), so it’s best to pre-soak the compost before starting.

Overall, this is one of the best heated electric propagators for smaller spaces, and also it’s good fun to have the propagator sit close by on the windowsill where you can easily watch the seeds germinate and grow.


  • Simple to use - just plug it in and turn it on
  • Highly effective when it comes to starting seedling growth
  • A good size for most window sills, with a slimline design
  • The individual trays and lids make it easy to plant a range of seeds
  • Raises temperature inside by around 8°C


  • Although simple to use, there are no controls and the heat is only increased by 8°C - so this propagator still needs to be kept inside on a warm windowsill
  • The clear plastic lid isn’t very durable and needs to be handled with care
  • There is no indicator light so it’s easy to accidentally leave it on

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Stewart Essentials Electric PropagatorStewart Essentials Electric Propagator

Best large propagator

Ease of Use
Value for Money

Stewart Essentials Electric Propagator Review


  • Seed Capacity: up to 144 seeds
  • Number of 'Cells': 1 tray
  • Power: 22 W
  • Adjustable Ventilation: Yes

If you want to ensure a high yield of germinated seedlings, this 22 W Stewart Essentials Electric Propagator allows you to plant up to 144 seeds at a time, which can result in germinating at least around 50 plants in one ‘round’.

Given that propagation can be a bit hit or miss, having space in this large 52 x 42.5 x 28 cm unit for so many seeds is certainly one way to help increase the chance of success. The more times you try, the more opportunities you have to succeed!

It’s a simple unit, that consists of a heated tray with a ventilated plastic lid – you supply your own trays/pots, but it can fit 2 x 24-pot plant trays, so that gives a good idea of its size in practical terms.

There’s only one open heating space, so you’re not restricted by smaller ‘cells’, but you also can’t ventilate seeds individually. The plastic lid has two vents, which can be opened or closed, to regulate the temperature inside the propagator.

However, if you’re after some other form of temperature control, there isn’t one – so taking temperature readings and opening the vents, or even turning off the unit for a brief time, is the only way to control the heat.

In terms of space, there’s plenty of room for seedlings to grow, considering the height of the unit is 28 cm; if you’ve made the mistake of planting out germinated seeds too quickly in the past, they’ll have plenty of space to develop and mature here.

As you may have realised, though, this isn’t a propagator that will fit on a standard windowsill as it’s quite big – it will likely need to be placed on a table, desk, or worktop if you’re using it indoors.

It will also likely need to be used with an extension cable, or placed close to a mains plug, as the power cord is relatively short.


  • Has a lot of internal space - can fit 2 x 24-pot seed trays
  • The adjustable ventilation panels offer relatively easy temperature and humidity control
  • The 28 cm height provides enough room for seedling to fully establish before needing to be moved on
  • Simple to use with easily adjustable air vents


  • The plastic lid can be a bit delicate - it needs to be handled carefully to avoid damage
  • The cable is fairly short so this propagator will need to be placed near a plug socket or used with an extension
  • There is no adjustable temperature control, just one set temperature
  • Due to its wide, square design, it's too big for most windowsills
  • There's only one heating space, so different seeds must be placed in the same conditions as each other

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Sankey Growarm 300 Electric PropagatorSankey Growarm 300 Electric Propagator

Best small propagtor

Ease of Use
Value for Money

Sankey Growarm 300 Electric Propagator Review


  • Seed Capacity: Not listed
  • Number of 'Cells': 3 trays
  • Power: 18 W
  • Adjustable Ventilation: Yes

The moisture mat provided in this 18 W Sankey Growarm 300 Electric Propagator makes it easier to look after seeds without needing to constantly check if they’re drying out.

It provides moisture to the unit, helping keep the humidity high and the soil damp, without you needing to frequently open and disturb the propagator to water the plants.

Three seed trays come installed in this large 52 x 42 cm propagator so you don’t need to purchase any pots of your own in order to get started. They all share the same heated space, and there is enough room under the 24 cm height to propagate cuttings as well as encourage seeds to germinate and grow.

As is often the case with these kinds of propagators, the clear lid is relatively flimsy – it’s made from thin plastic which needs to be looked after carefully to avoid denting and damage. That said, the two vents in the top are still very useful for controlling the temperature, although there’s no thermostat or other temperature regulator.

The vents have to be opened, or the propagator turned off at the mains, in order to change the heat inside the unit.

In general, though, this is a well-priced propagator for its size, giving plenty of room to germinate a number of seeds at a time, as well as enough space to propagate cuttings.


  • Comes with 1 large and 2 small seed trays included
  • Most users find their seeds germinate even in very cold weather
  • Very effective, with most seeds germinating in a couple of days
  • It is easy to operate the vents, and these do offer some temperature and humidity control


  • The temperature it reaches depends on the room temperature and cannot be controlled independently
  • There is no indicator light so some users find they leave it on for longer than they meant to
  • Some customers commented that the construction is a little flimsy
  • As this propagator is fairly large, finding a location for it may be difficult

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Things to Know Before Buying a Heated Electric Propagator

Getting your seeds off to a great start in life is made a lot easier (and quicker) with the help of a heated propagator.

Whether you are looking to germinate seeds early, or have been struggling to get seedlings to thrive, a heated propagator can provide very beneficial surroundings for young plants.

They create an environment that’s just a few degrees above air temperature, creating conditions that help many seeds to germinate. The best part is that they cost just a few pence a day to run.

If you want to buy a heated propagator, the following information should help clear up any doubts or questions you may have:

Choosing the Right Size

The size of propagator you should buy will depend on the space you have available, and how many seeds you want to propagate.

Take a look at the product’s dimensions and match them up with the space you have available – propagators come in a range of sizes, so you’ll find one to fit your space with a bit of searching!

To give an idea of size: there are units that are small enough to fit onto windowsills, whilst others will need to be placed on a table/worktop/greenhouse shelf.

Large, one-cell units that measure around 52 x 45 cm can be used to try to germinate around 140 seeds. They’re often big enough to fit 2 x 24-pot seed trays, and if you get 3 seeds in each pot, this can mean the potential to plant 144 seeds.

Some smaller units have individual ‘cells’ for each pot so you don’t have as much free range with how many different seeds you can plant at a time.

For example, on this page, there is a seven-cell propagator, which would make it possible to plant around 21 seeds (if you planted three seeds in each cell). However, the good thing with individual-cell propagators like this is that you can have better control over the temperature in each cell.

Having an idea about the length of the propagator’s cable before purchasing is also a good plan. Some propagators have short cables of 1 m, whilst others are slightly longer at between 2 and 3 m. Depending on where you have a power outlet, either in the house or greenhouse, you may have to use an extension cable.

Lid Height for Better Growth

The lid height will dictate how long you can keep your produce growing in the propagator – if the plants start pushing the ceiling, they’ll have to be taken out.

Generally, a height of around 20 cm will allow enough space for your seedlings to establish properly, giving them enough time to grow good roots and 3 – 4 full leaves before having to transplant them.

The tallest propagator featured on this page is 28 cm. This sort of height will give a lot of flexibility on the types of seeds and cuttings you can propagate in the unit.

Number of Compartments

The number of compartments will allow you to grow several types of different types of seeds; you can adjust the soil type and environment to suit the individual seed.

Most standard propagators either come with on large seed tray, or one larger tray and a few separate smaller trays. These may be contained under the same roof, or in individual ‘cells’.

If there are separate trays, or there’s enough space to use your own pots, you can have a lot more flexibility on using different soil types and planting different seeds.

Having a propagator with separate ‘cells’ will mean you can choose to ventilate certain cells and not others which allows you to adjust the environment to the individual seed.

For example, on this page, the Garland Super 7 Propagator is one of the best heated electric propagators for catering to different seeds; it has seven different pods and each one has its own ventilation. These type of set up allows you to keep some seeds cooler than others, all whilst using the same propagator.

The Effect on Your Energy Bill

The idea of adding a propagator to your house might seem daunting – doesn’t it cost a lot of money to have a heat source on for a long time?

Electric propagators can range in wattage, and the size of the propagator will also affect how much power you need. The wattage determines the cost of running it.

Generally, you want to be keeping the temperature of the soil inside the propagator at around 10 – 15°C depending on the seed. If there’s no thermostat or temperature control, you can use a thermometer to check the temperature and make sure the propagator isn’t on, using power, unnecessarily.

You can buy propagators that range anywhere from 8 – 100 W.

A propagator of between 13 – 22 W is generally sufficient for home use.

Calculating Running Costs

First, you will need to know how much your energy provider charges per kilowatt-hour. Let’s say they charge 14p per kWh (a relatively standard rate in the UK).

Then, you’ll need to multiply the wattage of the propagator by the number of hours it’ll be used each day. Divide this number by 1000 and multiply by 14 (or your specific kWh rate).

For example, if you run a propagator of 100 W for an hour, at this rate, it will cost you 1.4p for that hour. A propagator of 50 W will cost 0.7p for an hour. And a propagator of 22 W will cost you 0.3 p per hour.

As you can see, at these low wattages, keeping a propagator running is quite affordable.

Plus, if you get a propagator with a thermostat, it will regulate the temperature and save energy by turning off when it reaches a certain temperature.

A lower-wattage propagator will heat up more slowly, but cost less to run, than a higher-wattage unit.

A high-wattage propagator will heat up quickly; however, if there’s no thermostat then you’ll have to be around to turn it off, to stop it from heating unnecessarily and using up too much power.

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Heated Electric Propagator FAQs

What seeds require heat to germinate?

Most seeds germinate more effectively with some base heat. However, a heated propagator is particularly useful for plants that are usually grown in warmer climates as these generally need warmer temperatures to germinate.

If you are planning to grow tomatoes, chillies, peppers, aubergines, cucumber or melons then an electric propagator will be a worthwhile investment. Heated propagators are also useful for seeds which require a long growing season as they enable you to get a head start and maintain a consistently warm temperature.

How do I use my new heated propagator?

An electric propagator is very simple to use. Once you have planted your seeds in the trays or pots and watered them, simply put them into the propagator and turn it on.

You will probably not notice a great deal of warmth in the unit, however, you will see some condensation that will show you the unit is doing its job. If your unit has a capillary mat, then wet this under the tap and put it at in the base before putting your seeds in.

You can adjust the ventilation in your electric propagator as necessary, but bear in mind that the unit will dry out more quickly when the vents are open. Once the seeds have germinated and are beginning to grow, you can either remove them from the propagator or just unplug the unit if all the seeds have germinated. You can also increase the ventilation at this stage to gradually acclimatise the seedlings.

Where should a heated propagator be placed?

Place your propagator somewhere warm and sunny, but ideally away from direct sunlight. A sunny windowsill tends to be a good option.

If your propagator won’t fit on a windowsill, placing it on a table, desk or counter-top in a room that gets a lot of sunlight is another good choice.

Bear in mind the length of the power cable when placing your propagator – you may need to use an extension cord if there is not a mains socket nearby.

Remember to turn your propagator regularly, to encourage your seedlings to grow straight up and not bend towards the sunlight.

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