Seedling Success - How to Get it Right

To each their own (speed)

It's completely normal for different seeds to germinate at different times. For example, Did you know that it is quite normal that seeds do not all take the same time to germinate. For example, the 42-day red tomato will often germinate 7 days before the gardener's delight or the Oscar Gonthier even if sown at the same time. And sometimes, even for seeds of the same variety, they can be up to a 7 day lag between the first emergence and the last. Tomato seeds usually germinate with the right temperature in about a week, parsley 2 weeks, ground cherries 4 weeks...


Temperature plays a key role

For the germination period, it is important to maintain moist soil (not soggy as there is a risk of seed rot) AND an ambient temperature of more than 22°C. If your seedlings are on a windowsill and your house is at 20°C (therefore colder by the window when cloudy) and 17°C at night, this is enough to greatly affect the germination potential of seeds.


The container

Shallow plastic trays like the ones mushrooms and salad are sold in or yogurt pots cut in half are ideal for starting seeds, and you can recycle them year on year.

If you're just starting out on your gardening journey, avoid using cardboard containers, such as egg cartons and toilet paper rolls because the water is absorbed by the cardboard and sent back into the air quickly, meaning the soil dries out which harms your chances of germinating.

Also, their narrow shape does not leave enough space for the first roots, limiting the plant from the start and leading you to have to pot on early, which can stress the plant. If you are looking for a way to repurpose cardboard for your garden, simply add it to your compost!

Water, not too much, not too little

Forget what you've seen and stop using spray bottles. This technique generally only waters on the surface and so seeds will not germinate or will take much longer to germinate than expected. Use a fine stream of water that allows you to water deeply. I like to use a sports bottle, or an empty honey or ketchup bottle.

And don't bother with the clear plastic lids, bags or saran wrap. Unless you're a pro at adjusting humidity by opening the covering by varying degrees as needed each day, the humidity the cover is creating cannot regularize quickly and if you overwater your seedlings will rot. 


Choosing the right soil

Soil that is too heavy or too rich for starting seedlings can be harmful, as can a soil that is almost sterile and devoid of nutrients, peat pucks and soil that is too sandy.

How deep to sow? That's the easy part!

Follow the instructions on your seed packet or remember this handy tip - sow at 2 x the diameter of your seed. So, if your seed is 1 mm wide, you should sow it 2 mm deep. If you sow too deep, the seed will germinate but not reach the surface.

person sowing seeds in black cells

Look it's growing!

Once germinated, you'll want to provide light. Ideally 14-16hrs of light per day. If it is early spring, provide artificial lighting for seedlings and keep it about 3 inches from the plants to prevent them growing leggy.

When should I water?

Once the seeds have germinated, the soil can dry out between waterings. The temperature can drop to 20°C during the day and colder at night.

When should I thin out or pot on?

About 4-6 weeks after germination, transplant into richer 'growing' soil or add a little liquid fertilizer to the water.

How do I thin out or pot on?

Tomato, cucumber or squash plants are potted on under the base of the first leaves to encourage the growth of new roots that will help strengthen the plant. Other types of plants, flowers, herbs for example, are simply replanted in a larger pot without necessarily burying them deeper.

Should I nip out leaves?

Would you like to start in life and get a piece of you ripped off? Surely not. It would surely harm your development.

a young seedling

Don't forget to read our article about hardening off your plants before planting out! 

Happy sowing!