How to grow geraniums from seed for an abundance of pretty flowers

Christmas might be just around the corner, but now is it's the perfect time to learn how to grow geraniums from seed ready for them to burst into colour in summer.

Yes, while it's certainly simpler to grow geraniums from potted plants, there's something magical about sowing seeds successfully. Especially as it gives us an excuse to flex our growing powers in December.

'Zonal or ivy leaf geraniums are ideal for sowing in December,' says Morris Hankinson, director of Hopes Grove Nurseries. 'Use pots or seed cells to get them started, or recycle yoghurt pots or milk cartons. Just make sure they have drainage so the seeds don’t rot in wet compost.'

Tender geraniums (also known as pelargoniums) are actually a Mediterranean garden staple, bringing colour and cheer to gardens all summer long. While they're able to handle themselves in a drought, though, it's important to remember you will need to overwinter geraniums and protect them from frost, otherwise all of your growing efforts will go to waste when the temperature drops.

With that caveat out of the way, then, here's how to grow geraniums from seed...

What you will need

If you're looking to grow geraniums from seed, you will need

• A bag of Levington PEAT FREE Seed Compost (with added John Innes) from Amazon
• A selection of pots or seed trays from Amazon.
• Geranium seeds - try something like Geranium 'Quantum Red' Seeds from Thompson & Morgan or Pelargonium 'Designer White' (Zonal) from Sarah Raven for extra impact.

Step-by-step guide

Now that you have everything you need to hand, you're ready to go! And, thankfully, it's not all that tricky to learn how to grow geraniums from seed, as our step-by-step guide proves...

1. Prep the pots

If you want to grow geraniums from seed successfully, you'll need to make like the Scouts and remember that you should be prepared.

'Fill the pots with either a seed compost or mix two parts of seed compost with some perlite for good drainage for the seeds to germinate,' says Morris (you can pick up a bag of Gro-Sure Perlite from Amazon).

2. Sow and spray

'Sow the geranium seeds on top of the compost and gently press them so they are in contact with the compost,' says Morris, who notes that they shouldn’t be buried – or at least not too deep.

Morris Hankinson

Morris Hankinson is the founder and managing director of Hopes Grove Nurseries Ltd, the UK’s only specialist grower-retailer of hedging plants. He established the thriving business in 1992, shortly after graduating with a Commercial Horticulture Degree from Writtle College, Essex.

'Spray with water using a fine mist so the seeds don’t drown or wash to one side of the pot,' he adds.

3. Cover and check

Next on the How To Grow Geraniums From Seed 101 checklist is to cover your potted seeds carefully.

'You can either use a clear plastic lid or a clear sandwich bag to ensure the moisture if retained around the seeds,' says Morris. 'Each day, be sure to lift the lid or bag for a few hours for ventilation.'

He adds that 'geranium seeds do need to be kept warm and humid to germinate, so using a lightly warmed heated propagator or mat can be useful'.

The Stewart Heated Propagator from B&Q is a good option to invest in, but you can also simply place your pots on a warm, sunny windowsill.

4. Thin out the seedlings

If you're wondering how to grow geraniums from seed, it's worth noting that you'll have to get to work thinning them out once they've sprouted.

'When the seeds have germinated the cover can be removed and when the seedlings have grown their first true set of leaves, they can be thinned out by simply snipping the stems off of the weaker seedlings,' says Morris.

'Eventually as they grow, each strong plant can be potted up.'

5. Show them some TLC

Finally, it's time to shower your baby geraniums with love and affection so they can grow up big and strong.

'The seedlings will need bright light (but not direct) sunlight and for the soil to remain moist but not overwatered,' says Morris. 'Watering in a tray at the bottom is ideal because it minimises the chance of dampening off which will be the end of your seedlings!'

By next spring, he says that you will be able to harden your geraniums off after all risks of frost have passed so that you can plant them out.

FAQs

How long does it take to grow geraniums from seed?

They might be easy to grow, but geraniums will take a relatively long time if you start them from seed. Your flowers should take 13-15 weeks after you've sown your seeds, all being well.

If you follow the steps on our guide carefully, you should easily master how to grow geraniums from seed. And, if you get to work before Christmas, your flowers will be ready and raring to go when the sun is warming up in 2025.