Last updated on May 11th, 2021
Our site is reader supported, this means we may earn a small commission from Amazon and other affiliates when you buy through links on our site.
For optimal results, growing your plants from seeds requires a stable and controlled environment, and for that you need a propagator. We look at several types of seed propagators – heated, self-watering and non-heated – that give your plants a strong head start in their lives. We list the pros of each model along with a discussion of their benefits and our recommendation. Our Buyer’s Guide and FAQ section help you choose which propagator is best for you and then start to use it.
Our Best Pick is the Stewart Variable Control Electric Propagator. This propagator lets you choose the interior temperature from 12o-28o C and keeps it constantly there for a stable environment for your germinating seeds and seedlings.
Our Runner-up is the Garland British Made Big 3 Electric Propagator. This is a straightforward non-heated and non-self-watering propagator but has an extra-large growing space and an amazing 37.5cm of headroom for tall plants.
Note: You may be a bit confused at first as some of the propagators look identical in the photos. You’ll find, though, that they have different features. For example, one may have an adjustable thermostat and the other may have a single temperature.
7 Best Propagators we review in this guide
- Stewart 52cm Propagator With Adjustable Thermostat – Best Pick
- EarlyGrow 24″ x 15″ x 16.75″ Domed Propagator – Runner-up
- Garland Super7 Heated Propagator
- Stewart Essentials Electric Propagator
- Super 7 Self-watering Propagator
- Garland 24 Cell Self-watering Propagator
- Garland British Made Big 3 Electric Propagator
1. Stewart 52cm Propagator With Adjustable Thermostat
The Stewart 52cm Propagator With Adjustable Thermostat has the same quality, durable construction and crystal styrene clear cover we’ve come to expect from this brand. The clear cover provides optimal clarity and maximum light transmission for a better germination rate. Air vents on the top of the cover control humidity and air temperature.
The adjustable thermostat allows you to set the temperature anywhere between 12 and 28 degrees Celsius using the dial. The 50W heater is more powerful than the heater fund on most other heated propagators. This is ideal for plants that require a specific temperature to germinate.
Included in your purchase is a handheld temperature probe so you can directly check the temperature of the soil in the pots and make any temperature adjustments necessary.
You can use this model anywhere, from a windowsill in your home to a shelf outdoors in your greenhouse.
- Adjustable temperature propagator with a range between 12o-28o C to suit whatever temperature your seeds germinate best at.
- Heater is 50W to provide the right amount of heat for germination.
- Clear styrene cover lets in the maximum amount of light for your seedling’s best growth.
- The temperature dial is easy to access; just turn it to set the correct temperature.
- Air vents in the lid open and close easily as an additional control for the temperature and humidity.
- Temperature probe (included) lets you check the temperature of the soil in the pots directly to make sure that the plants are in their optimal environment.
- Comes with one large seed tray, two small seed trays and ten flower pots.
The Stewart 52cm Propagator With Adjustable Thermostat is our recommendation if you are a gardening enthusiast and experienced gardener. If you sow a variety of plants, the adjustable temperature gives each variety of seed the best temperature to start their growth. And you can check the temperature of the soil in each container with the handheld probe to ease your worries about whether the seeds are in the right environment for their best growth.
The only downside is the price, as it is more expensive than a non-adjustable thermostat propagator and more than double the price of a standard heated propagator. That being said, this is a premium propagator and worth the investment.
The Stewart 52cm Propagator With Adjustable Thermostat is our choice for Best Pick of the propagators in our review. This propagator makes it easy to give your seeds the best environment for the first phases of their lives and takes the worry out of doing so.
2. EarlyGrow 24″ x 15″ x 16.75″ Domed Propagator with 3 Height Extenders and Locking Clip Set
The EarlyGrow 24″ x 15″ x 16.75″ Domed Propagator with 3 Height Extenders and Locking Clip Set is neither heated nor self-watering. But that does not mean that it’s just a simple propagator. This is a model to consider seriously if you plan on starting many plants out from seeds or if many of your seedlings are going to grow really tall.
From its title above, this EarlyGrow propagator has a tray that’s 60cm by 37.5cm. That’s a significant growing space for starting your seeds out. The tray is made from heavy-duty plastic that’s strong enough to carry pots of fully grown plants without bending or becoming wonky. The clear lid is also made of strong plastic that won’t become brittle if you use grow lights above it. Two vents in the lid let you change the temperature and humidity inside the unit by letting air in.
But the really unique feature of this propagator is that you can extend the headroom between the tray and the lid – a lot. Your purchase comes with three height extenders and more are available at an extra cost. As your plants get taller, clip-on a height adjuster for an extra 12.5cm or so of vertical space for them to grow into. Using all three extenders gives you 37.5cm of headroom.
The extenders clip to each other and to the lid, forming one piece. This makes it easy to remove the entire cover to get into the propagator to look after your plants. Each height extender is made of clear plastic and has a vent on the side. This is because your plants need more ventilation as they grow.
- Extendable propagator with a heavy-duty tray so you can safely carry heavy pots without the unit bending or buckling.
- Height extensions let you add headroom as your plants get taller.
- The clear lid has two vents to open or close to control the temperature and humidity inside as your plants need.
- Height extensions have their own side vents for further control of the interior climate as your plants get bigger and taller.
- Height extensions lock into place and to the lid and can be removed in one piece when you want to water or tend to the plants inside.
- The extra-large tray holds 60 5cm x 5cm seed planting cells so you can germinate a lot of seeds at once.
- Not heated.
- Not self-watering.
The EarlyGrow Domed Propagator with 3 Height Extenders may not have the features of a heated or a self-watering propagator, but it does extra-large growing space and vertical height. Germinate all your seeds at the same time and then add on the extensions as the taller plants take off. The clear lid can handle any grow lights that you use for light and warmth – you just have to remember the watering schedule.
We recommend the EarlyGrow Domed Propagator with 3 Height Extenders for anyone who starts tall plants from seed or loves to have their seedlings really established before transplanting. It’s the Runner-up in our review of the Best Propagators.
3. Garland Super7 Heated Propagator
This Super7 heated propagator by Garland is designed to fit on most windowsills which is the position a lot of gardeners choose as the ideal location to propagate seeds. At 76cm long and 18.5cm wide, this heated propagator has a 13-watt carbon fibre element which warms the compost evenly by about 8°C. There’s no thermostat for you to set, but most seeds and seedlings are comfortable at this heat.
This propagator has 7 individual seed trays each with its own clear lid, making it ideal for sowing a selection of plants at the same time. The lids are shatterproof and each have their own vent so you control the environment (including ventilation and so humidity) within each mini-propagator separately.
- A single temperature propagator (non-thermostat) raises general compost temperature by 8°C which is what most seeds need to germinate.
- The base tray holds seven individual germinating units so you can sow seven different varieties of seed if you wish.
- Crystal clear lids are shatter-proof and let in the maximum amount of sunshine.
- Vent in the lid of each mini-propagator lets you set the environment for each type of seedling individually.
- Minimal control over the internal environment.
- Small growing areas.
- Only for indoor use.
What we’ve identified as Cons for the Garland Super7 Heated Propagator make it perfect for people who want to start just a few seeds indoors without much fuss and bother. This is the simplest heated propagator in which you don’t have to worry about the perfect temperature for each variety of seed, and you can sow just a few seeds of each type. You just adjust the vent according to how the seedling’s doing and remember to water them.
We recommend the Garland Super7 Heated Propagator for those gardeners who want to start a few seeds of different varieties indoors or those who are just starting out doing this and are not sure if it’s really for them.
4. Stewart Essentials Electric Propagator
The Stewart Essentials Electric Propagator looks the same as our Best Pick but this model does not have an adjustable thermometer. Instead, the 8-watt heating element heats the compost a preset amount (unspecified) that most seeds can germinate at.
The vents on the top of the crystal styrene lid open and close to also control the temperature along with the humidity. As this propagator has just one interior unit, all your seeds are in the same environment so they should all like the same conditions. However, you have the choice of whether you sow them in seed trays or pots or whatever fits into that space.
This Stewart propagator is designed for only indoor use, so don’t use it out into your greenhouse.
- Single temperature (no thermostat) propagator that heats to the compost a preset amount to provide a warm environment for your seeds to germinate in.
- The heating element has 8w of power to keep the interior space at a suitable temperature for your seeds and seedlings.
- Single interior space lets you plant your seeds in whatever containers will fit inside.
- Vents on the top of the crystal lids let you control the humidity and also the temperature within.
- For indoor use only.
The Stewart Essentials Electric Propagator has an 8w heating element that is more than enough to hold the compost at a comfortable temperature for your fledgeling seedlings. You do have some control over the interior environment of the single growing space by adjusting the vents on the top of the lid and by mixing and matching the trays and pots you plant the seeds in.
The Stewart Essentials Electric Propagator is a good choice if you want to provide a heated growing space for your seeds and you’re not concerned about providing a different environment for each variety.
5. Garland Super 7 Self-watering Propagator
Not to be mistaken for the Garland Super7 Heated Propagator we reviewed previously, this Super 7 Self-watering Propagator is for those who would rather automatically provide water than heat to their germinating seeds and subsequent seedlings. This is an unheated propagator so do make sure that your windowsill or wherever you place it is warm enough to encourage the seeds to start growing.
This self-watering propagator has a built-in self-watering feature to keep the soil moist. It works by having an outer water reservoir tray that stores water and in which sits some capillary matting which wicks up the water. The seven mini seed trays then sit on top of the capillary matting which retains water and then the compost and plants take up the water using capillary action as and when needed. as long as you make sure the tray has water in it, the plants take what they need and won’t be under or over watered
The green containers and their clear covers are built from strong injection moulded plastic which makes them rigid and shatter-resistant. You control the interior temperature and humidity of each container by adjusting its individual vent in the top of the cover.
- Self-watering propagator for those who aren’t so good at remembering watering schedules.
- Seven mini propagators sit in a single tray to keep them organized and tidy.
- Individual vents in the lid of each propagator let you control the temperature and humidity of each one separately.
- The container and lid are made of shatter-proof plastic for strength and safety.
- Grow a different type of seed in each propagator for maximum variety.
- Not heated.
The Garland Super 7 Self-watering Propagator is for those people who already have a warm enough spot in their homes that don’t need a heated propagator and can now release the task of watering their seeds to their propagator. The slim design means it fits onto a windowsill easily making it very appealing. The seven mini trays are ideal if you grow a variety of plants as they can be sown separately and each have their own environment.
We recommend the Garland Super 7 Self-watering Propagator for those who don’t need a heated propagator and who don’t want to remember to check their variety of budding plants for water every day.
6. Garland 24 Cell Self-watering Propagator
This Garland 24 Cell Self-watering Propagator has 24 cells and is a very budget-friendly choice. Although it is not heated, it is self-watering, taking one daily worry away from your spring garden preparation tasks.
This model has an internal water reservoir and on top of this, there is a lining of capillary matting which attracts the water. The seed tray sits on top of this and the plants then draw water from the capillary matting when needed. As long as there’s water in the tray, the plants can’t over or under water themselves.
For the eco-conscious gardener, this unit is made from recycled plastic and is designed to be reused. It’s not the strongest plastic but will probably last a few years if you’re not too hard on it.
- A self-watering propagator has 24 individual cells so seedlings won’t bother each other.
- Internal water reservoir with capillary matting that takes water up to the plant so you don’t have to.
- Tray and cover made from recycled plastic for the eco-conscious gardener.
- Slim design so comfortably fits on a sunny windowsill or shelf.
- Indoor use only.
- Not heated.
The Garland 24 Cell Self-watering Propagator is an unheated propagator that’s a step above the slightly less expensive regular 24-cell plastic propagator. But for the few extra pounds you don’t have to constantly worry about your compost getting too dry or becoming over-watered. Just make sure that the windowsill or shelf that you place this on really does receive enough warmth and sunshine to let the seeds germinate and the seedlings grow strong.
We recommend the Garland 24 Cell Self-watering Propagator for anyone who wants just a basic propagator tray and who has a habit of over-watering or forgetting to water their plants.
7. Garland British Made Big 3 Electric Propagator
The Garland British Made Big 3 Electric Propagator provides an extra-large growing space divided into three separate full-size propagators, each with its own cover. All three propagators share a single tray that keeps them together and organised.
This Garland propagator is thermostatically controlled and heated by a 50w heating unit. Each propagator is kept at a constant 19°C to ensure the best growing temperature for your seeds, seedlings and plants.
You can override this by opening the vent on top of each propagator to change its interior temperature and to affect the humidity. Effectively, each propagator can have its own environment to suit whatever variety of seeds you’re growing there.
As well as having more growing space than usual, you also have more headroom with this Garland model. The high-top covers give you more vertical space so feel free to grow tall plants or leave your seedlings in there for longer if the weather outside is not suitable yet for transplanting them.
If you’re planning on putting this on a windowsill or a small shelf, check the dimensions as this model is indeed extra large.
- Single temperature propagator maintains the temperature at a constant 19°C for an optimal environment for your seedlings.
- Heater provides 50W of power to this extra-large, shatter-proof propagator.
- Three large propagators sit in a single tray to provide a variety of large growing environments.
- High-top clear covers provide extra headroom for tall plants and seedlings.
- Single vent in each cover lets you adjust the humidity and heat in the propagator.
The Garland British Made Big 3 Electric Propagator provides plenty of space for those who are serious about starting all their annual flowers and vegetables from scratch. This heated propagator holds the three individual units thermostatically to a constant temperature of 19°C which seems to suit most plants. Let your tomatoes grow a little taller than usual within the extra tall covers to ensure they’re really ready for transplanting.
We recommend the Garland British Made Big 3 Electric Propagator for serious gardeners who want to be there from the very beginning of their plants’ lives.
Knowing the entire life story of the plants in your garden is possible if you use a propagator to start them from seeds. You only need to make a few decisions when choosing the best propagator for your style of gardening and what seedlings you’re aiming for. Here’s what you need to know.
Why use a propagator?
Propagators can be used to help cuttings strike and take root, but they are most commonly used to aid the germination of seeds. By using a propagator you can control the seed’s initial growing environment and get a better success rate of germination and strong seedlings
Types of seed propagators
Germinating seeds and growing seedlings needs these elements: heat, light, nutrients and water. Whichever of these your propagator and grown medium doesn’t provide, you must.
The basic propagator consists of a seed tray and a transparent clear lid. They are simple to use and help to retain moisture, which stops the seeds and seedlings from drying out. They also keep the air inside slightly warmer than the outside environment.
Heated – no thermostat
These provide a consistent temperature which is pre-set by the manufacturer. The heat is usually constantly on and cannot be turned off. These are ideal for lots of seeds but are may not suitable if you are growing different types of seeds that will germinate at various temperatures. The pre-set temperature make by a set temperature (e.g. 19°C) or maybe a temperature difference (e.g +5°C over the ambient temperature).
Heated – with thermostat
Often regarded the holy grail of propagators, these are heated propagators that come with a thermostat that you can set to within a range of temperatures. Set this to your required temperature, usually between 5°C and 30°C, so the environment is perfect for the type of seed you’re growing. These work by regulating the temperature to within 1°C.
These propagators have a water reservoir that wicks water up to the plants (and potting medium) through capillary action via a capillary mat). The plants determine how much water they need and when they need it. These propagators are ideal if you have a habit of under or over watering plants. You just have to ensure that the water tray or reservoir doesn’t run dry.
Be realistic about how many seeds you want to germinate and plant more than that in case some don’t come up. Also, check the dimensions of the propagator before you buy it. Some have a slim design that fits on a windowsill and others are determinedly extra large and need a dedicated growing table.
Think also of the size the seedlings need to grow to before you can transplant them. Some may grow to be quite tall, and so look for propagators with extra headroom.
Not all propagators are suitable for use outside in your greenhouse, though all can be used inside your home. Assume that the propagator can’t be taken outside unless the information of its box tells you otherwise.
Alternate heat and light source
If you really need a self-watering propagator or your budget doesn’t stretch to a heated unit, consider an alternate form of heat and light. Chances are that in the UK you don’t have a sunny and warm enough window sill to germinate your seeds. You need to consider a grow lamp, perhaps one on a timer so you don’t have to remember to put it on and off on the right schedule.
What are the basics of using a heated propagator?
- Ensure that you plant the seeds carefully using clean equipment to avoid contaminating the growth environment. The seeds have to be in touch with the compost to optimize maximum growth.
- Set the temperature that is required to promote plant growth if your heated propagator has a thermostat.
- Place the seed propagator somewhere with good natural light to promote the growth of cuttings.
- Avoid lifting the lid unnecessarily which will disturb the temperature and humidity levels inside the propagator.
- If there is too much condensation, make use of the vents to release excessive moisture.
- Ensure you water your seedlings but do not flood the seedlings as the water may affect the electric circuit of the propagator.
Do you water seeds in a propagator?
Yes, you can water seeds in a propagator but the aim is not to flood the seeds. It is advisable to soak the seed pots in a shallow tray to permit the compost to get wet. Once the compost is wet the seeds can get moisture from the compost without exposing the seeds to too much moisture or compromising the electrical components.
Do I need a heated propagator?
This depends on the plants you are trying to grow and the region that you are in. Some seeds require certain temperatures to germinate. Given the cold British weather, a heated propagator would be of service to you all year-round and can speed up the amount of time it takes for seeds to germinate and also the success rate. For example, peppers often germinate much quicker in a heated propagator.
Having the ability to control and manage your plant’s growth environment is empowering. Whether you want to grow chillies, tomatoes or any herbs, you can rely on your propagator to provide a secure environment. Just ensure that you read the instructions on both your seed packet and propagator to ensure you have everything in order. After that, you can rest easy knowing that soon you will have healthy seedlings in your hand ready for a transplant.
Our Best Pick of propagators is the premium Stewart 52cm Propagator With an Adjustable Thermostat. This is the only propagator in our review that lets you choose the temperature from within a range to ensure that your seeds grow up at the optimal temperature for that variety.
The Runner-up is the EarlyGrow 24″ x 15″ x 16.75″ Domed Propagator with 3 Height Extenders and Locking Clip Set. This is a simple propagator that is neither heated nor self-watering. But it does give you a large growing area and an amazingly tall vertical space.
And, of course, everyone needs to try growing Tomatoes Plants from Seed.
Below is a quick reminder of our ‘Best Pick’
Last update on 2021-09-15 / Affiliate links / Images from Amazon Product Advertising API