The Best Propagator – Buyers Guide (2021)

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Anyone wanting to germinate their own seeds is going to need a propagator. There are three main things that a seed needs to be able to grow: moisture, oxygen and warmth. The main point of a propagator is to help create the perfect environment for your seeds to grow with the perfect temperature, perfect moisture and perfect amount of oxygen. Not only this, but they will help to keep your seeds safe from birds, pests and other insects that could damage or completely end the growing process. 

There are many different types of propagators to choose from depending on your budget, the seeds that you are wanting to grow and the amount of care and protection you are expecting from your propagators. This article will look at the different features you will find in varying propagators so that you can find what is going to be right for you.  

Best Pick – Garland Super7 Electric Heated Windowsill Propagator

Garland Super7 Electric Heated Windowsill Propagator G51
987 Reviews
Garland Super7 Electric Heated Windowsill Propagator G51
  • Perfectly sized for the windowsill
  • Features seven mini propagators
  • Measures 76cm long by 18.5cm wide by 15cm high

Last update on 2021-05-08 / Images from Amazon Product Advertising API / As an Amazon Associate I earn from qualifying purchases

In A Hurry?

If you are wanting to start germinating your own seeds immediately then this is the part of the article you need to read. We have filled it with all the essential information that you are going to need to decide which is the best propagator for you. 

Heated or Unheated? 

The first thing that you need to think about is whether you want a heated or unheated propagator, as that is going to make the biggest difference in the options that you have to choose from and the price bracket that you need to look at. 

A heated propagator is the best way to help your plants to grow to their fullest at all times of the year. One of the main reasons why people use a propagator is to maintain a desired temperature for your seeds. This is obviously going to be much easier to do with a heated propagator as you will be able to control the exact temperature that you need. However, they are going to be more expensive and you have to consider where you are going to position them as you will need to be close to a source of electricity. A heated propagator basically works through the use of a heat mat that is placed under the seedlings. This is controlled either manually or via a thermostat (more on this below) to maintain the temperature. 

An unheated propagator is going to be a much cheaper option as you are basically just buying a planting tub with a plastic lid – although admittedly there is much to it than that. These are going to rely on the warmth of the sun coming through the plastic covers to heat the seeds on the inside, which saves you having to worry about positioning them near an electric source however there are downsides to this. As with many conservatories, you will find with unheated propagators that they can get too warm during the day (particularly during bright, summer days). You can also find that they will cool quickly at night and won’t be able to protect your seeds from the cold should the weather change unexpectedly – which we know can happen quite regularly in Britain. 

TOP TIP: Heated propagators will usually work in roughly the same temperature variation but this is definitely worth checking for, particularly if you are wanting to grow more abstract, unusual plants. Most are going to be able to maintain temperatures between around 15℃ and 25℃. This also usually depends on the temperature outside the propagator so make sure to check! 


The size of your propagator really depends on the number of seeds that you are wanting to work with – but there is actually more to it than just that. Obviously a bigger propagator is going to allow you to work with more seedlings at once, but there are some downsides to larger propagators which could mean you are actually better with a smaller model – particularly if you are trying to grow more delicate seedlings or you are new to the germination process. Larger propagators are going to take longer to heat up, which is obviously going to mean more electricity is needed as your propagator will need to be switched on for longer periods. Not just this, but one of the reasons you have a propagator is to hold the moisture inside as this is good for the plants….however (like with most things in life) it can be a case of too much of a good thing is actually a bad thing! If you have a large number of seedlings in one propagator then this can create a large amount of moisture, this can lead to rotting of the seedlings if you are not careful to manage it! 

The size of most propagators tends to range from around 18cm up to around 80cm for domestic use propagators. 

TOP TIP: As a side note, it is also worth considering where you are actually going to keep your propagators as they are going to need to be around sunlight if you are wanting the seeds to grow successfully. Many large propagators won’t actually fit on windowsills so you are going to need a greenhouse or table that they can be positioned on in the sunlight. 


The actual design and build material of your propagator really comes down to personal preference and budget. Some budget propagators are essentially a tray of bedding pots with a plastic lid on top, which will be capable of doing the job to a certain extent but does quite limit your options. However, what we do like about these makes is how little extra work/money you need to invest. The benefit of them coming already sectioned into different pots means that you can simply fill them with compost, plant your seeds and you are ready to go. But they do tend to be made from much more flimsy “one-life” plastic,  which means that they can become damaged a lot easier. 

Your other option is to go for more of a sturdy plastic tray design which you can then fill with your own tubs or trays. The benefits of these are that they allow you to work with whatever pots of different sizes that you want depending on the seedlings that you are growing. Not only this, but you have the flexibility of adding different pots of different sizes at the same time (providing you have the space). You will also find that the plastic that is used tends to be much more heavy duty, meaning that you can use your propagator time and time again with relatively little damage or wear. However, you do need to bear in mind that these models will require you to have your own growing pots which can add to the initial outlay! 

Essential Features 

Once you have decided on whether you would like a heated or unheated propagator and the size of propagator that is going to be best for you, it is time to think about the features that you are going to need to turn your little seeds into beautiful plants. 

  • Ventilation – For us ventilation panels are a must in your propagator. This helps to reduce the heat and moisture level in your mini greenhouse to stop it from getting too much for the little seedlings that you are growing. We love propagators that come with adjustable ventilation panels as this will allow you to close them during the night and then open them again in warmer weather during the day. Some of the smaller models will come with only two vents but the bigger models have up to five.
  • Thermostat – Unless you already have an unused thermostat we would definitely recommend purchasing a propagator that has one included. To ensure the best growing conditions for your seeds it is going to be essential that you can check the temperature of your propagator. Propagators that come with a thermostat included will usually have them positioned on the side of the lid so that you can quickly check the temperature to make sure your seeds are happy and thriving! 
  • Sectioned – We love propagators that come in different sections. This allows you to adapt the conditions for each type of seed that you are growing or the different stages of germination that they are at. 
  • Drainage holes – Check the design of the different propagators to make sure that there is going to be a way for excess water to drain away. This may be as simple as through drainage holes but if it works then that is all that matters as it will prevent root rot in your seedlings as they start to grow.

Best Budget – Garland High-Dome Propagator

Garland GAL19LP Large High-Dome Propagator, Green, 37x22x19 cm
682 Reviews
Garland GAL19LP Large High-Dome Propagator, Green, 37x22x19 cm
  • Strong injection-moulded trays
  • Crystal clear vented lid - higher than the average to allow for stronger growth
  • Two-tier drainage holes to avoid waterlogging
  • Made in the UK from 97% recycled plastic

Last update on 2021-05-08 / Images from Amazon Product Advertising API / As an Amazon Associate I earn from qualifying purchases

The Best Propagator Features 

There are so many propagators out there to choose from it can be difficult to know which really are the BEST. Here are some of the additional features that we found on the best propagators to help you sift out the ones that you should be buying. 

  • Self-regulating propagators – There are many reasons why a self-regulating propagator may be best for you! Not everyone has the time to be checking on their seedlings all the time. If you are working, have a family, or just have other things to do with your time, then a self-regulating propagator may be best for you! This basically works by having a thermostat that you can set an optimum temperature on. Your propagator will then try its best to maintain this temperature using the heat mat (although remember that your propagator could still become TOO warm and this is something you will have to manage yourself).
  • Self-watering – Some of the more complex propagators are also self-watering, using a store of water to keep the soil moist in your tubs. 
  • Double layered – Some of the best propagators come designed as a double layer. This is a great way to not only save space when you are germinating seeds but also allows you to adjust the humidity levels by adding or removing the top layer. 
  • Wattage – If you opt for a heated propagator then check for the wattage that it offers as this is going to determine the power that it is able to release when heating! There is quite a large variation from around 15 watts up to around 50 watts! 
  • Extras included – It is worth looking if there are any extras that come with your propagator to make it better value for money. We found that some come as germinating “kits” with pots to plant in, thermostats, moisture readers etc. This is going to save you money in the long run if you are able to buy everything in one go! 
  • UV Protected Plastic – If you are wanting a longer lasting propagator then it is worth checking if the plastic is going to be coated with UV protection, this will stop it from discolouring as it is exposed to sunlight so regularly. 

Best of the Rest

RINBO Seedling Heat Mat,Heating Mat with Digital Temperature Controller,with LED and Probe,Adjustable 6 Temperatures and 6 Timer Sets,Reptile Plant for Gardening Greenhouse,Waterproof (10'x20.75')
1 Reviews
RINBO Seedling Heat Mat,Heating Mat with Digital Temperature Controller,with LED and Probe,Adjustable 6 Temperatures and 6 Timer Sets,Reptile Plant for Gardening Greenhouse,Waterproof (10"x20.75")
  • 【UPGREAT VERSION】: This is the Latest Adjustable Version, Digital Temperature Controller. Which designed with adjustable 6 temperatures and 6 timer sets. The waterproof sensor probe provides more accurate temperature control. Thermostat controller will improve propagation rates by maintaining ideal root temperatures between 40-110°F (5-42°C). Control device allows gardeners to select and maintain optimum rooting temperatures for faster seedling and cutting growth.
  • 【PRINCIPLE】: The Seeding heat mat is used to increase the success rate of germination, root cutting. Maintains a consistent heat effectively raise rooting area temperatures approximately 10-20°F above ambient air temperature. Bottom heat excites seeds into thinking it's spring.Can be used greenhouse, nurseries and indoor gardens. More efficient than trying to heat an entire greenhouse or shed, faster plant growth and seed germination.
  • 【VARIETY OF USES】: Provides constant temperature to improve vegetable, plant, herb, and flower seed germination. Also perfect for home brewing, ferment water Kafir, brewing kombucha and pet enclosures terrariums, such as those used in reptile, rodent and arachnid. Grow your own peppers, tomatoes, cucumbers from now on.
  • 【DURABLITY】: Silicone heating wire and heavy duty multi-layer construction. Internal insulated wiring for enhanced safety. Super Material-fully waterproof, fray proof and durable. Easy to clean, can be rolled up to store when not in use. Power-off protection. Watt:30. Power Cord's Length: 78.86in/200cm; Instructions is printed on the surface for your convenience
  • You can get a bigger variety of plants from seeds, cheaper than buying all the seedlings from the nursery. We want you and your plants to thrive. Happy planting! 6 months Manufacturer Warranty. Reply to the email within 24 hours.

Last update on 2021-05-08 / Images from Amazon Product Advertising API / As an Amazon Associate I earn from qualifying purchases

EarlyGrow MPL50115/2 Large Shatter Proof Propagator with Two Vented Height Extender Sets for Seed Germination and Plant Growth - 58 x 38 x 32cm
111 Reviews
EarlyGrow MPL50115/2 Large Shatter Proof Propagator with Two Vented Height Extender Sets for Seed Germination and Plant Growth - 58 x 38 x 32cm
  • Shatter proof lid and sides are UV stabilised and crystal clear to allow for maximum light from either sunlight or grow lights for optimal plant growth
  • Adjustable ventilation control for air flow and humidity to give your plants the best environment to grow in
  • Sow seeds and cuttings organically with compost directly into the base or use smaller trays. Alternatively use coir or for hydroponic growers, rockwool or other growing medium
  • Large sized propagator with two extenders is 58 x 38 x 32cm providing space to grow lots of plants
  • Made in the UK from robust and durable injection moulded plastic makes our propagator reusable and made to last many years with care

Last update on 2021-05-08 / Images from Amazon Product Advertising API / As an Amazon Associate I earn from qualifying purchases

Plant Theatre 3 Funky Propagator Pods - Gardeners Gift Idea
390 Reviews
Plant Theatre 3 Funky Propagator Pods - Gardeners Gift Idea
  • Set of 3 colourful propagator pods - great new idea as...
  • Unlike conventional rectangular propagators, you can rotate the whole pod or individual pots to enable plants to grow towards the sun
  • Each funky propagator pod has a base (colours red, green and yellow), clear lid and 8 x 6cm dia pots
  • Ideal accessory gift with Plant Theatre’s selection of seed kits: Funky Veg Kit, Psychedelic Salad Kit, Hot Chilli & Sweet Pepper Kit and the Herb Garden Kit
  • Gift Boxed. Makes an ideal gift for children and gardeners alike

Last update on 2021-05-08 / Images from Amazon Product Advertising API / As an Amazon Associate I earn from qualifying purchases

Frequently Asked Questions 

What is the best temperature for seed germination in a propagator? 

This is obviously going to depend on the seeds that you are working with but you will usually find that seeds need a consistent temperature of between 18 and 20 degrees celsius. It is important to check for each individual seed though as some need very specific conditions to grow. Remember it is the soil temperature that is important when looking at seed germination – not the air! 

How long does it take for seeds to germinate? 

This, again, depends on the seeds and plants that you are hoping to grow. Some are as little as 3 days whereas others are up to 10 days. Check for each individual plant as this will then help you to judge whether your propagator is providing sufficient warmth to the seeds. 

When can I take my seedlings out of the propagator? 

We would usually recommend STARTING the process of removing your seedlings once they have their second or third leaves. However, this is a slow process and will also be affected by where you are moving them to. Make sure to start by just lifting the lid from your propagator on warm days, once you think they have survived this point you can start leaving the lid off all the time (if the outside temperature is warm enough), then move them to a greenhouse to continue to grow. 

  • Performance
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  • Ergonomics
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