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Seedlings in propagator trays on a windowsill

Tips for sowing seeds early

Boost your success with early-sown seeds, by following our practical tips.

Sowing seeds early in the year can reward you with plants that will flower or crop earlier than usual.

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To boost your chances of success, there are several things you can do to counteract the effects of low light levels and stuffy indoor temperatures – both of which can encourage damping off. This fungal disease can sweep through trays of seedlings, usually attacking them at roots and the bases of stems, causing them to topple over and die.

When you’re ready to go, check out what to sow in January.


Use a heated propagator

Sowing seed early - using a heated propagator
Sowing seed early – using a heated propagator

Most seeds germinate between 18°C – 22°C, which is not normally achievable early in the year – even indoors. A heated propagator will provide a consistent temperature throughout the day and night, which ensures the best chances of germination without heating the whole room. Models range from budget propagators that provide a basic level of heat, to more expensive models that enable you to adjust the temperature. Always use a propagator lid to keep the heat in and save energy.

Heated propagators are available in a range of shapes and sizes, so to help you choose the right one for you, we’ve put together a guide to the best heated propagators, which provide the perfect growing conditions for seedlings. You might also find our guide to the most useful greenhouse accessories helpful if you’re looking to update your greenhouse kit.


Use a growing lamp

With low light levels early in the year, seedlings can quickly become leggy and etiolated. Growing them beneath a lamp will ensure they grow strong and healthy.


Practise good hygiene

Wash pots, seed trays, propagators and anything else that comes into contact with seeds and seedlings thoroughly, then rinse with greenhouse disinfectant.

Scrubbing plastic plant pots clean
Scrubbing plastic plant pots clean

Use new compost

Don’t use up old bags that have been lying around outdoors, even if unopened. For best results, start a new bag of compost. Alternatively, why not try making your own compost? Our comprehensive expert guide takes you through how to choose the best compost bin for your garden, the pros and cons of the different types, as well as what to put in your compost bin and how to make your own compost.

A new bag of compost
A new bag of compost

Blend your own growing medium

Create your own special growing medium for particular seeds by adding vermiculite, perlite, and/or silver sand or fine grit. If you have space, either in a greenhouse or on a patio, a potting bench is the ideal place to mix your own growing medium. We’ve found the most stylish and practical designs on the market in our guide to the best potting benches and trays for the garden.

Mixing vermiculite into compost
Mixing vermiculite into compost

Use fresh seeds

Start with new packets of seeds as these germinate fastest and more seedlings result – old seed may not come up at all, wasting time and resources. Why not treat yourself to a seed box, which is the easiest way to keep your seeds all in one place. There are plenty of styles on the market, from robust, steel tool boxes to personalised, handmade containers. Check out our round up of the best seed boxes.

A seed drawer, categorised by month
A seed drawer, categorised by month

Water carefully

Water seeds in after sowing, then water them as sparingly as you dare after that, but don’t let your seedlings dry right out. Check them daily. Make sure your watering can has a rose on it, which is more gentle than a single jet of water, and won’t damage delicate seedlings. We’ve selected ten of the best watering cans, so you can pick the perfect one for the job.

Alternatively, you can attach a spray gun onto a hose pipe. Looking for a new spray gun? Check out the best spray guns, which have been tested by our experts so you can buy in confidence. We’ve also tested a range of hoses to create a guide to the best garden hoses.

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Thoroughly watering seeds after sowing, with a rose head watering can
Thoroughly watering seeds after sowing, with a rose head watering can

Transplant seedlings promptly

Seedlings that are growing in seed trays should be transplanted as soon as they have their first pair of true leaves, to give them the space they need to grow healthily and to avoid damping off. Use a pencil or dibber to prick out and transplant seedlings into their own pots – check out our round up of the best dibbers for seed sowing, where we’ve found something to suit every style and budget.

How To Prick Out Seedlings