How to pot up seedlings

Do try this at home. You will need

a work bench

pots

potting mix

water

seedlings

 Seedlings growing and waiting to be potted up, above black plastic containers full of water which keep the glasshouse warm at night.

I sowed tomato, cucumber, broccoli and many other vegetable seeds in punnets and pots in the lean-to glasshouse on August 17. The glasshouse is not heated, but we store the sunshine overnight in large black plastic containers of water kept under the bench. These heat up during the day and release heat slowly after dark. Vegetable seeds and seedlings don't need a lot of heat to germinate and grow (15 degrees C is the minimum required) but they do better if the temperature is kept as even as possible.

Tomato seedlings with their first true leaves are ready to be potted up.

One month later some of the baby seedlings have their first true leaves (the ones that look like the leaves of the adult plant). They are therefore ready for potting into larger pots where they can grow to the size they need to be for planting out in the garden (or sharing with friends, family, neighbours and good causes). 

Shake the potting mix gently around the plant, holding it upright as you do so.

There is only one thing you really need to know to pot up seedlings successfully – DON'T SQUEEZE THE STALK. The stalk is the main trunk line carrying water, nutrients and energy between the roots and the leaves. If you crush or bend its delicate tissues during potting up it will not be able to do its job properly, and the seedling will not flourish.

So hold the seedling by one of its seed leaves, lower the plant delicately on to the damp potting mix in the pot, shake more potting mix carefully around the roots and stalk until the plant can stand up unaided, then gently tamp the potting pix around the plant before watering it.

That's it. Keep the potted-up plants warm and well-watered, and within 3 or 4 weeks they will be ready for planting out in the garden.