Welcome to my WTF Gardening series, where I take common gardening terms and explain them for those who are new to the world of plants. Find the entire WTF Gardening series here.
It’s one thing buying plants from a garden centre or nursery that have already been partially grown – that’s the easy part! Growing plants from seed often requires more care and attention, and involves two processes that you may not yet be familiar with: ‘sowing’ and ‘pricking out’.
Understanding both of these processes can help you get the hang of growing plants, so that you can get even more satisfaction from your plant journey, whether you’re growing flowers, foliage or your own produce.
What is sowing?
Let’s start with the very first step when planting seeds. Once you’ve obtained your seeds, whether from a shop or harvested from plants that already exist in your garden, the next step is to sow them.
Different plants will have different sowing requirements, with factors including soil type, watering schedule, and whether they need sowing into a tray or straight into the garden. It’s best to research the individual needs of each plant before you try to sow it, or you might put in all that effort for nothing! In this blog post, I’m talking about general sowing, which can be applied to a wide range of common plants.
When plants emerge from their seeds, they’re very fine and fragile, so they need a light compost that they can push through in order to reach the surface and start to sprout.
Seed composts are different to multi-purpose composts. The latter are usually too heavy and nutrient-rich for seeds to grow. Dedicated seed composts are finely milled, well-draining and contain a balance of nutrients that are appropriate for seeds. If you only have access to multi-purpose compost, try mixing one part compost to two parts potting soil.
You don’t have to have a seed tray – small seeds can be grown in almost any container as long as it’s around 2-3” deep and has drainage holes at the bottom. Seed trays just fit these requirements perfectly.
Sow larger seeds in pots of around 3.5” in diameter, or module trays, as they’ll require a bit more room.
Certain plants, such as a wide variety of annuals, biennials, herbaceous plants and vegetables, can be sown straight into the ground. This is great for those who don’t have room to sow inside – but you have to wait until the conditions are right, and make sure to prep the area in which you’re planting.
To sow outdoors, the soil should be cleared of weeds and the surface should be crumbly so that the seeds can sprout through. To ensure this, you can break up the soil using a trowel. The outdoor conditions should be frost-free, and the soil itself should be warm and moist (as a general rule in the UK, these periods are between April-June and throughout September; however, you should refer to the individual plant’s requirements to make sure). And, remember, any autumn-sown seeds may not emerge until the spring.
As I’ve mentioned, the soil should already be moist when you plant your seeds, I usually start with a slightly moistened compost. Check the soil daily for moisture levels. The soil should be kept just moist, but definitely not waterlogged.
What is pricking out?
Once your seeds put forth shoots and develop two or more sets of leaves, they require transplanting into a larger container. This is called pricking out, and only applies to seeds that have initially been grown in trays or small containers. It requires a very delicate touch to ensure that you don’t damage the plants at this very fragile stage!
You may also notice your seedlings still have some seed casing attached. They’ll often shrug this off in their own time, but if there’s any issues, remove it carefully with tweezers,
How to prick out your seeds
- To make the roots of each seedling easier to separate, water them around an hour before you are going to transplant them.
- Prepare your containers. Choose pots that are 3.5” in diameter, and fill them with a seed compost.
- Carefully lift the seedlings out of the trays using a pointy tool such as a pencil or dibber.
- Pot each seedling into its new pot at the same height that they were previously growing. If they’re leggy, plant them slightly deeper. Gently firm the compost around the stem with your fingers.
Once you’ve pricked out your seedlings, place them in a bright, warm area (but not in direct sunlight) to continue growing. If you want to know more about lighting and positioning, I’ve got another blog post on this here.
What would you like to see me cover next in my WTF Gardening series? Let me know in the comments section!
Michael has been involved with gardening and plants since he was just five years old. He is a self-professed Plant Geek, and was listed in the Sunday Times top 20 most influential people in the gardening world, thanks to his plant hunter role at Thompson & Morgan.
Michael was responsible for new plant introductions such as the Egg and Chips plant and the FuchsiaBerry and keeps busy travelling the world in search of new plants as well as lecturing worldwide, including stints in Japan. He is very active on social media – so why not give him a follow at @mr_plantgeek or Facebook. You can also listen to The Plant Based Podcast with Michael and co-host Ellen-Mary on iTunes, Spotify and Google.