Seed tray filled with soil and a yellow plant label by a windowsill
Growing plants from seed is a joy to experience. Follow our step-by-step guide to sowing small seeds in trays, including ways to make it easier.

Helpful information

Timing: Check seed packet for recommended sowing time

Where to do it: Indoors or outdoors

Garden space: Large garden, small garden, balcony, indoors

  • This provides gentle exercise and may help build strength and coordination
  • Watching seeds grow can engage your nurturing instincts, with hope and anticipation for the future
  • Observing the first tender green stalks defying the odds and breaking out from the compost. It seems like a small miracle every time it happens!

Easy read guide

Sowing seeds is also available as an easy read PDF guide. Find our easy read guides here.

A wonderfully wide variety of plants can be grown by first planting seeds into trays. Here are some good plants to start with. You can read the information on any individual seed packet to discover if it is suited to being sown in a seed tray.

Vegetables and herbs

Tomatoes, peppers, chilies, basil, parsley


Geraniums, cornflowers, poppies, marigolds

Some plants that have very long roots, like sweet peas, are better grown in root trainer pots or toilet roll tubes.

The excitement of seeing my own seeds growing into little baby plants is one that I will never lose or forget.

Nikki, gardening blogger

Make it easier

If small seeds seem too fiddly, start with larger seeds such as courgette, sunflower or even garlic bulbs. Plant these into small pots instead of trays.

You can skip seed sowing completely and buy plug plants instead. These are young plants that have already germinated from seed. Plant them directly into the ground or into pots and containers.

Essential items

  • Packets of seeds
  • Small seed trays with drainage holes. Choose a modular seed tray (one already divided into separate units) for easier growing
  • Multi-purpose compost or seed sowing compost
  • Watering can with rose
  • Plant labels and pen (lollipop sticks also work well)

Optional items

  • Perlite or horticultural sand to mix with your compost to improve drainage
  • Root trainers. These specialist seed trays are longer than regular ones and can be opened so you can check your plant’s growth
  • Potting or tidy tray. This high-sided tray creates a really helpful workstation that stops compost spilling. For some, a washing up bowl or kitchen tray also works
  • Ruler for sweeping compost flat and measuring seed distances

Tools to make it easier

  • Bright yellow tape (e.g. electrical tape)
  • Scissors to open compost bag and seed packet
  • Scoop or small flowerpot
  • Small coloured plate or bowl
  • Seed sowing grid or cut cardboard or seed spacing ruler
  • Flour to mix small seeds with
  • Seed dispensers for small seeds, or a folded piece of paper or wet toothpick
  • Colander/sieve
  • Easy read labels. You can find a range of large clear print, coloured, tactile and braille labels from the RNIB
  • Small watering can
  • Bottle top waterer

Follow these steps to sow seeds in trays with ease.

Step 1: Gather what you need

Container with seed tray, soil, seed packet and gloves and watering can beside it
Seed sowing equipment including compost tidy, seed tray and compost

Get together all the items in the ‘what you need’ list above. Find a suitable space in your home or garden. This could be indoors, in your conservatory, greenhouse or outside at a table.

Make it easier

Make sure your seed sowing area is at a comfortable height, especially if you have difficulty bending. Make sure it’s easy to reach everything you need.

If you are sitting down, have your elbows and shoulders at right angles. This avoids pressure on tendons and joints.

If you are using a tidy tray and have any visual impairment, put bright yellow tape around the edges. This makes it easier to see the working area.

Step 2: Prepare your compost

Gloved hand holding compost
Compost lumps being gently broken up by hand

Open your compost bag. Mix it around with your hands and break up any big lumps (wear gardening gloves if you wish). This helps air and water get into the compost, which will help the plant grow.

You may choose to mix perlite or sharp horticultural sand into your compost to improve drainage. This is optional, not essential.

Make it easier

You don’t have to buy huge bags of compost. Smaller 10-litre bags with handles for carrying are available.

Scissors may be necessary to open the compost bag at this stage.

If you find it hard to mix compost in its bag, put a manageable amount in a washing up or mixing bowl. This way you can work from a better height.

Step 3: Fill the seed tray with compost

Compost being added into tray using a small flowerpot
A small flowerpot is used to carefully fill the seed tray with compost

Add your compost to your seed tray until it is slightly overfilled. Then use your hands, or a ruler, to gently sweep the compost so it is flat and level.

You want the compost to end up a few millimetres beneath the top edge of the seed tray. Lightly tap the side of the compost tray to help the compost to settle.

If the compost is filled to the top, when you water your seeds, the water can run off the edge taking your poor seeds with it! If the compost level is too low, it stops the seeds getting enough light. This can make seedlings grow tall and ‘leggy’ (a bit thin and scraggly).

Make it easier

Find a scoop to help fill your seed tray, like a small flowerpot. Remember that you don’t have to fill your tray in one go.

A tidy tray or washing up bowl will help reduce mess.

Step 4: Place the seeds on the compost

A hand placing small seeds into the sections of the seed tray
Seeds are carefully placed in each section of the seed tray

If you are using a modular seed tray, place two or three seeds in each section. This number can vary depending on the size of the plant and how reliably it grows.

If using a non-modular seed tray, check the seed packet for advice on distance between seeds.

Make it easier

Sowing seeds can be fiddly, especially if you have arthritis or a weak grip. Do little bits at a time and take breaks.

Scissors may be necessary to open the seed packet at this stage.

As you sow seeds, keep your spare hand on the seed tray so you can methodically work your way through each section. A stick or plant label can be helpful to mark your spot, in case of an unexpected distracting phone call!

Picking up seeds
Pour the seeds from the packet onto a small plate or bowl that is a different colour to the seeds before sowing. This can make it easier to pick them up.

Very fine seed can be mixed with horticultural sand (or flour if you don’t have sand) to make it easier to pick up and sow. You can then take a pinch at a time and sprinkle it over the compost. The sand or flour also makes it easier to see where you have placed your seeds.
Placing seeds
A seed sowing grid can help you space seeds in a non-modular seed tray. These are not readily available to buy, but you can make your own. Cut cardboard to the size of your seed tray and punch holes in it to the correct distance. Seed sowing rulers are also available and have holes already prepared.

A seed dispenser can make placing seeds easier. Or, you could use a wet toothpick to pick up each seed. Or you could fold a piece of paper with seeds in and tap it over the seed tray to dispense.

Step 5: Cover the seeds with compost

Sieve being used to sprinkle compost over seed tray
A sieve is used to gently cover the seeds with a top layer of compost

Most seeds need a fine layer of compost sprinkled over to cover them. Check the seed packet for advice. Gently tap the side of the tray to remove excess compost once added.

Make it easier

If you are worried about being heavy handed, use a sieve/colander to sprinkle compost over your seed tray.

Larger seeds can be gently poked under the surface of your compost.

Step 6: Label your plants

Yellow plant label with cress written on it placed at edge of seed tray
A bright yellow plant label shows seed variety and date sown

Plant labels are fantastic to remind you what you planted! Add the date sown so you know how long your seeds take to germinate.

Place labels at edge of tray facing out to let you easily identify what each tray contains.

Make it easier

A simple way to make a plant label is to stick the plant packet on a stick in the seed tray.

If you have sight loss, there are a variety of options available to help you create larger or easier to read labels. Some gardening companies produce extra-large labels. A range of large clear print, coloured, tactile and braille labels are available from the RNIB.

Step 7: Give them a water

Bottle top waterer spraying water over the seed tray
A bottle top waterer is used to give the seeds a gentle water

Your new seeds will be thirsty! It’s time to give them a gentle water. You can either do this by watering from above or from underneath.

If watering from above, the standard method is to use a watering can with a rose on the end. A rose is a large, circular nozzle attachment with tiny holes in it, allowing water to come out as a gentle sprinkle. When watering, you want the soil to become moist, not soggy.

If watering from underneath, sit your seed tray in another tray of water. Leave it soaking until the seed tray feels heavy to lift. This approach stops your seeds getting washed away or being pushed too deep into the compost.

Make it easier

Small watering cans are available from garden centers to minimize heavy lifting.

Bottle top waterers for plastic bottles are useful and good for reusing old bottles.

Lightly water your compost before putting it into the tray. This will mean it is already moist when you sow seeds.

Step 8: Position your seeds

Step 8 Position your seeds
A seed tray positioned in a light spot on a windowsill

Place your seed tray in a light spot. A warm windowsill, preferably facing south, is good. You could also put your tray in a greenhouse or mini propagator if you have one. Make sure they are somewhere you can easily reach and monitor.

Position the tray away from draughts, which can dry out compost and harm tender seedlings.

Your seeds are now successfully sown and in place. This is a great time to reward yourself with a cup of tea!

For the best chance of success with your seeds, keep the compost moist but not saturated. Use a watering can with fine rose or indoor water spray.

Make it easier

Some fabric cut to size and placed under your seed tray will hold moisture meaning you have to water less.

Hopefully, you will soon see the miraculous first green shoots poking through the soil as your seeds germinate. Once they have grown big enough, the next stage is 'pricking out'. This means carefully moving them into bigger pots.

If you used a modular seed tray, you may not have to prick out your seeds. You may be able to leave them for longer and jump straight to planting them out . This is a great way to make seed sowing that bit simpler!

Top tip

There are no mistakes in gardening, only chances to learn. It’s very normal for some seeds not to germinate, or others not to grow well. Don’t be disheartened. If this happens, just look at their growing location and see if there is anything you could change next time.

Help us continue to make gardening accessible for all. Make a donation to Thrive today. Thank you.

Make a donation

Sign up to receive gardening inspiration and tips to get the most out of your own gardening space, and improve your health and wellbeing at the same time

Choose which aspects of the gardening information service you’d most like to hear about.

Double your donation today!

The Big Give is back! Any donations from now until 5th December will be matched. Visit our Big Give page today.

Find out more