There’s something quite remarkable about growing your own plants from seed. There’s a real sense of accomplishment when you see the first signs of growth emerging from the soil. And it’s not as hard as you might think.
The secret to successfully growing seeds optimally is based on a few basic principles. If you succeed, you will be rewarded with seeds that will germinate and grow into healthy seedlings.
To help you get the most out of your seed growing, I spoke to Brian Talman, Seed Trials Manager at Mr Fothergill's, who shared his expert advice and some secrets on how to best grow seeds. Plus, after watching Talman perfectly demonstrate how to sow seeds, I put his advice to good use myself when sowing basil seeds at home.
Compost
One of the secrets to growing seeds is compost. Talman advises, “Choose a compost that’s designed for seedlings,” adding, “But be prepared to pay a little more for good compost.”
He uses coconut fibre compost, sometimes called coir, made from coconut husk fibres. Mr Fothergill has developed his own enriched version, which also contains seaweed and slow-release nutrients.
Coco compost is often sold compressed and dry, making it compact and lightweight. However, before using it, you will need to rehydrate it in water for a few minutes to prepare it for use. Be sure to read the instructions on your specific product to find out how much water to add.
Talman explains that once you add water to dry compost, you get a nice “light, fluffy mix,” as the coco coir is designed to retain moisture and promote a healthy root system.
Talman advises against using peat-free compost, however. “Many peat-free composts contain nitrogen, which blocks seeds.”
Air
The second important element is to make sure the compost is aerated. “When you fill a pot, you don’t want to make it so compact that there’s no air left in the compost,” Talman says.
A light, fluffy compost is therefore essential for seed growth and root development, as without oxygen the seeds will remain dormant and will not germinate.
Water
Seeds need water to germinate, as well as quality compost and air. However, they do not like to be flooded and it is best to vacuum the compost from the bottom of the pot rather than from the top.
“If you water from above, the water should go straight into the soil, which is what good compost should be like. It should receive the water, hold enough of it and not act like a pond,” Talman says.
However, watering from below will ensure that the seeds do not drown before they have a chance to germinate, or the compost will become so compacted that the air is squeezed out.
Additionally, to help regulate humidity, Talman adds a soil additive to his pots. “To keep some air and moisture around the seeds, we add vermiculite to the top of the pot. We prefer vermiculite over perlite because if you have seeds sitting in a pot for a few weeks, the perlite tends to turn green and can encourage flies.”
What is vermiculite?
Vermiculite is a soil additive that helps improve soil texture, improve water absorption and drainage, and regulate compost moisture.
How to sow seeds in the best way
If you don't feel like getting your hands dirty, grab a pair of the best gardening gloves before handling the compost.
If you are using a dry coco fibre compost, add the required amount of water to it before you prepare to plant your seeds. However, it won't take long. I only had to wait 5 minutes before I could start sowing!
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1. Slightly fill a 4 in. pot to the top with your chosen seed compost. Make sure the compost is loose rather than compact.
2. Gently press down on top of the compost. You can use the bottom of another pot. You should get a shallow rim.
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3. Place the pot in a dish of water and let it absorb the moisture for about 5 minutes. Avoid watering the compost from above as this will compact the soil and affect aeration. I was able to skip this step because I had just rehydrated my coco compost and it was nice and moist.
4. Lightly sow the chosen seeds on top of the compost according to the instructions on your seed packet.
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5. Place a thin layer of vermiculite on top of the seeds.
6. Place your pot on a sunny windowsill and wait for the seeds to germinate.
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How to sow beautiful seeds
There are many seeds, such as green beans and zucchini, that are large and easy to handle when sowing, but very fine seeds are much more delicate. In this case, Talman does not place vermiculite on top of the pot and sows the seeds without covering them.
He refers to lobelia and petunia seeds as being particularly good and explains his best tip for sowing them: “I dip a planter in water, touch the seed, then place it on the compost.” He repeats this process until he has sown all the seeds he needs.
Rather than using a specific dibble, Talman relies on the tip of a pencil.
Frequently Asked Questions About Sowing Seeds
Will the seeds need watering?
“You won’t need to water the pots until the seeds germinate,” Talman says. “If you keep watering, you’ll eventually seal the seeds in.”
Will I need to thin out the seedlings?
If your seeds have germinated and the seedlings are growing too close together, it is best to thin them out so that the stronger seedlings can have more nutrients and room to grow.
When will the seedlings be ready to transplant?
“You’ll know they’re ready to move when the roots come out the bottom,” Talman says. This is a much more reliable method than relying on the number of leaves growing, which doesn’t necessarily indicate a strong root system.
To soak or not to soak?
I have never soaked seeds before sowing them, but I wanted to hear directly from Talman if and why I should.
“Soaking the seeds promotes germination, and they will germinate twice as fast,” he says.
Soaking sweet peas can be particularly beneficial because the seeds are hard and soaking softens them. Talman recommends placing the seeds in a pan of water with a small amount of dishwashing liquid and then letting them soak for 24 hours.
Why add detergent? “Many seeds can have mold, mildew and mildew on their shells. If you sow them directly in the ground, you will never see them, but if you sow them in pots or cells, the mold will probably develop before the seed.”
The soaking process softens the seeds and also cleans them to promote healthy growth. Talman adds that nasturtium seeds are prone to disease and particularly benefit from cleaning before sowing.
What to Avoid When Sowing Seeds
It's easy to do Mistakes when sowing seeds —Sowing too many seeds can cause them to erode before you have time to transplant them. “It’s essential that the seeds have enough space to germinate and do their job,” Talman says.
Damping-off is a seedling disease caused by several different fungi or molds. It is common in young seedlings, especially those grown indoors or under glass. Infected seeds “damp out,” collapse, and rot. This usually occurs when seeds are in a very humid environment, have poor air circulation, or are sown too thickly.