Whether you’re starting seeds off in these cold, winter months, encouraging cuttings to root or raising tender plants originally from warmer climates, a heat source will help create the best conditions to nurture them. Heated propagators are an ideal accessory which, depending on the type you choose, either offers a consistent, ambient temperature or can be set at a particular temperature to suit your needs.
Because of our cooler temperatures, plants like tomatoes, chilli and bell peppers and squashes need a long growing season so that they have time to grow, produce fruit and for the fruit to ripen. Germinating them indoors in a heated propagator early in the year, when outside it would be much too cold for them to grow, ensures they get the long growing season they need.
Even hardier and native plants benefit from being germinated at a constant temperature. Thanks to their bottom heat and high humidity, heated propagators can also be instrumental in helping cuttings to take root. Whatever you’re growing, a heated propagator will protect germinating plants from sudden cold snaps like we’re having at the moment.
Growing other plants? Check out our guides to the best self-watering planters, or the best garden cloches. And if you're growing in a greenhouse, our 11 useful greenhouse accessories article will be worth a look.
How to choose a heated propagator
Consider the following when shopping for a propagator:
- Space - Unless you have a greenhouse with a power source, most of us will use a heated propagator at home. Position it on a flat surface; a windowsill out of direct sunlight is a good spot, but make sure the dimensions of your chosen propagator are a good fit.
- Size - Make sure the dimensions of the propagator are right for your needs. If you’re planning to grow on tender plants you’ll need a bigger propagator than if you're germinating seedlings.
- Features - For most projects, a basic heated propagator is fine. However, if you’ve the budget to spare, look out for self-watering propagators. Some also come with lights to further help propagation.
Heated vs non-electric propagators
A non-electric propagator is simply a seed or modular tray with a transparent lid that aims to provide seeds and young plants with a consistent growing environment. The lid helps to increase the humidity within as well as generate and trap warmth, particularly if placed in a sunny spot. Some have ventilation in the lid and may even have watering spots so you can water without removing the lid and splashing plants. Lids can also be purchased separately so you can add them to your seed trays as you need them.
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Non-electric propagators are a lot cheaper than a heated propagator, but without the extra, regulated warmth and bottom heat that you get in a heated propagator, growth will be slower and less consistent.
- Plant your seeds in damp compost, in the trays provided.
- Place your propagator somewhere light and well-aired.
- Switch on the propagator.
- Keep an eye on your germinating plants. If excessive condensation forms on the inside of the lid, open the ventilating holes to regulate the temperature a little.
13 of the best heated propagators
Browse our selection of heated propagators, below:
Garland Fab 4 Electric Heated Propagator
The Fab 4 propagator is a great entry-level propagator for new gardeners. It gives a first-time user ease and simplicity without compromising on quality. With four cells, it's great for growing a range of plants for the first time and easily keeping track of what’s what.
Garland Super7 Electric Heated Propagator
This heated propagator from Garland is built for propagating in bulk and can grow seven different cells of plants at once. If you’re after a bumper harvest, this lengthy propagator can give a host of plants a head-start.
Thompson and Morgan Heated Propagator with Air Valve
This propagator can be used without trays, so if you have lots to grow - little tomato plants, or a mix of cuttings, for example - this propagator is fantastic for general use. Great for running lots of small scale projects at once.
Harrod Horticultural Electric Starter Propagator
If you’re keeping a close eye on your energy bill, this electric propagator from Harrod Horticultural is a good option, with the 10 watt heated base using only a sixth of the power of a normal lightbulb. The lid has an adjustable vent which lets you have control over the humidity levels in the propagator depending on what you’re growing.
Selections Jumbo Windowsill Heated Plant Propagator
This heated propagator is designed to fit on a windowsill, and has a single deep tray that can either be filled directly with soil or pots, which is a useful feature when you’re growing your own. A thermostat control maintains heat at 21°C/70°F, while two vents in the clear lid regulate humidity.
Stewart Thermostatic Heat and Grow Electric Propagator
This generously-sized propagator has plenty of space and its extra high, clear lid allows excessive moisture and warm air to be released via two vents. An inbuilt thermostat maintains temperatures between 18°C - 23°C (64°F-73°F).
EarlyGrow Heated Electric Shatterproof 2-bay self-watering propagator
Simply plug in and use, this heated propagator produces a steady temperature ranging from 16°C - 21°C (60°F-82°F). Made in the UK with robust and durable shatterproof lids, it’s ideal for novice gardeners as it’s self-watering. The individual bays allow you to grow multiple seeds or cuttings simultaneously without fear of confusion.
Sankey 38cm Growarm 100 Propagator Kit
This model comes with 2x21cm seed trays to allow you to grow two types of seed at the same time, a capillary mat to retain water and keep soil moist, as well as an instruction booklet to get you started. The 8 watt heating element keeps the soil warm and is ideal for seeds that benefit from bottom heat.
Garland One Top Electric Propagator
This small propagator is a great choice if you’re strapped for space, or just want to grow a few chillies on the windowsill. Using even less energy than it takes to power a light bulb, seedlings will benefit from the constant, extra warmth. The vent is a useful feature, which helps control humidity levels, and though its footprint is small, its clearance is 12cm, which is plenty of room for young plants to get started.
Garland Big 3 Automatic Temperature Control Electric Propagator
For a truly bumper season’s growth, look no further than the Garland Big 3. This monster propagator holds three 37.5cm by 23cm trays at once, so you can give kale, tomatoes, sweet peas and chillies a head start at a balmy 19°C, all at the same time.
Harrod Horticultural Large Propagator with Height Extender
This large propagator is perfect if you’re growing large plants of cuttings, and it can also be moved outside to allow seeds access to direct sunlight once the weather warms up a bit. Until we get there though there’s a heated mat which works at 15C above the ambient temperature to help plant germination and growth.
- An alternative solution to providing seedlings and plants with some bottom warmth, heat mats provide the ideal warmth for a range of seeds, such as tomatoes, parsley, basil, cabbages and onions. Simply lay it out flat on a dry, even surface underneath a tray of seedlings or pots.
- However, without a cover, they’re unable to create humid conditions, which can be beneficial when seeds are germinating and the soil needs to stay moist. They’re great for storage, too, as they can simply be rolled up and put away until next year.
Riogoo Seedling Heat Mat and Thermostat
The thermostat sensor probe maintains a stable temperature between 20°C - 42°C (68°F-107°F), and features a digital keypad, which is easy to operate. It comes with a one year warranty.
ROOT!IT Heat Mats
Provide bottom heat to seed trays and pots to help speed up germination and cuttings to take root. Hard-wearing and easy to use, this mat can be wiped-clean and rolled up after use. It with a 1.8m power cable in three sizes - small, medium and large.
Price: from £36.99
This Product Guide was last updated in January 2023. We apologise if anything has changed in price or availability.