How to propagate seeds indoors
Plant propagation is an incredibly rewarding aspect of gardening – it lets you grow more for less and gives you a sense of achievement from watching your seed grow into a fully matured plant.
Whether you’re raising flowers for borders, filling the gaps in a vegetable patch, or growing hardy perennials, seed propagation doesn’t have to be too difficult.
Successful seed propagation comes down to a few steady principles: good seeds, the right compost, and carefully sowing under the right growing condition. Get those right, and you’ll have beautiful blooms by the time summer arrives.
Plant propagation from seeds
Propagation is a great way to get started on a range of garden plants, including vegetables, herbs, hardy annuals, and many perennials – sometimes you’re able to grow select varieties that aren’t always available as young plants, too.
Typically seed-grown plants can adapt better to local conditions, especially if raised slowly, which then produces sturdier growth and fewer problems later.
What seeds are good for propagation?
Vegetables such as tomatoes, courgettes, and salad leaves.
Herbs, particularly annual and tender types like basil.
Hardy flowers such as sunflowers, cosmos, and hydrangeas.
Annual climbers including sweet pea and morning glory.
Depending on the type of plant you’re trying to grow, some will germinate more quickly than others. Be sure to check the seed packets for any useful guidance on sowing times and conditions before you start.
How to sow seeds successfully
Sowing seeds doesn’t have to be difficult and doesn’t require too much equipment, a simple set up is usually enough.
What do I need for propagation?
A watering can with a fine rose
Perlite (optional)
A clean cover, such as a propagator lid or clear plastic tray
A bright, sheltered place to grow your plants
How to start growing from seeds
First things first – decide how many plants you’d like to grow, and sow a few extra just in case there are any losses.
Fill your trays or pots with compost, making sure its filled to the corners, then firm gently to create an even surface.
Most seeds are best sown thinly to prevent overcrowding. Fine seeds can be scattered evenly, whilst larger seeds are best placed individually.
Cover each seed to their own depth, but double check with the packaging as some need light to germinate. Used peat-free or sieved compost to cover them lightly.
Water carefully, we’d suggest a fine spray to avoid disturbing the seeds. Alternatively, you can stand the trays in water and allow moisture to soak up from below.
Be sure to label everything clearly so you don’t forget what you’re growing in which pots!
How to germinate seeds
To encourage germination it’s best to keep your seeds in a warm place like a windowsill or greenhouse/growing house, provided they’re protected from direct sunlight. You can use a windowsill propagator for the best results if growing inside. Turning trays regularly helps keep growth even, too.
However, once seedlings appear, the main priority is light. If your seeds are kept in dim light then it will lead to a thin, stretched growth that’s difficult to correct later.
Germination times will vary depending on what you’re choosing to grow – some emerge within days; others can take a few weeks.
Whilst you’re waiting keep misting, but don’t over water your seeds. Compost should stay moist, not be fully saturated.
Getting germinated seeds to grow
Once your seedling has emerged, remove any covers to improve airflow.
Keep them in a bright position and water lightly as needed.
After the seedlings develop their first true leaves, they can be pricked out into individual pots. Handle by the leaves rather than the stems, and plant them at the same depth they were growing before.
As your plants grow, move them into larger pots so the roots have space to develop.
Steady growth produces stronger plants, so don’t push them to grow too quickly.
Perlite can be used in place of soil in some instances – simply mix with water (but don’t saturate), insert your seed, and cover with a plastic bag, lid, or wrap to create a humid environment to encourage root growth.
How to deal with seed propagation problems
Of course, some problems can arise when propagating seeds, but they can be rectified if dealt with swiftly and correctly.
Patchy germination can be caused be uneven moisture, incorrect sowing depth, or unsuitable temperatures.
Weak seedings are usually a sign of insufficient light or overcrowding in the pot.
Damping off is where seedlings collapse at soil level and is linked to excess moisture and poor hygiene – keeping your containers clean and careful watering can help prevent it.
Grow your own seeds with confidence
Seed propagation rewards patience and careful attention. With the right compost, careful sowing, and consistency, most seeds will grow and germinate without trouble.
From vegetables from herbs and flowers for borders and containers, growing from seed is one of the most dependable ways to raise plants and broaden what you grow.
If you’re propagating for the first time, have a look at our comprehensive beginner’s guide to propagation, or drop into your local Dobbies and speak to a member of our Green Team who are happy to help with your next growing project.