Which seedlings shouldn't be started too early (they freeze!)?

Spring is back! The buds are here ready to release their colourful, glossy leaves. However, if on your calendar spring is noted on 20 March, that doesn't mean you should start all your seedlings. Each seedling has its own particular needs in terms of warmth, so let's look at what you should plant and when. To help you, here's your calendar so you can get organised as best you can for the sowing season.

Which seedlings for which period?

You can't wait to sow your little seeds in your pots, but it's necessary to adhere to the sowing calendar, particularly when sowing in warm climates. Indeed, tomatoes, peppers, courgettes or even aubergines are what we call warm climate seedlings. Whereas kohlrabi, turnips, onions... These are cold climate seedlings.

Why? Quite simply because the former will not tolerate a low temperature, whereas the latter can germinate at a temperature of around 7°C. Tomatoes, for example, need soil temperatures of over 15°C to germinate, while peppers, aubergines and courgettes require a minimum temperature of 18°C. If your soil is too cold, your seeds will take longer to germinate and are more likely to rot, particularly because of the humidity.

What are the consequences of sowing too early?

If you've decided to do all your seedlings, but you can't get them out, you could soon find yourself with an Amazonian forest at home. Not only are your seedlings at risk of wilting if they don't get the optimum light-to-heat ratio. But the biggest risk is that you'll end up with seedlings that are ready to be planted in the ground, but can't be because of the climate. Your plants could then wither if they are left in pots for too long.

It's also important to bear in mind that seedlings need time to adapt. Once the temperatures outside are high enough, you can take your seedlings out into the shade, but only during the day. If the nights are too cold, there's a risk that the seedlings will die or suffer a thermal shock that will stunt their growth later on. Then, as you go along, you can place them in half-shade and then in the sun. However, they cannot be placed in scorching sun. This adaptation is important before transplanting your plants into the ground.

What can I do in the meantime?

It's a well-known fact: there's never a dull moment in the garden, and for good reason - there's always work to do. So while you're waiting for the soil to warm up enough to receive your vegetable plants, you can start decompacting your soil with a grelinette. This tool will allow you to aerate the soil without breaking your back and while respecting the biodiversity in it.

If you have sown a plant cover, you can cut it and incorporate it into your soil so that it delivers all the nitrogen captured as it breaks down. This will nourish your soil and improve its biodiversity. Good things come to those who wait. As soon as the good weather returns, you'll be able to watch your plants grow in your vegetable garden to your delight!