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Planting seeds and germination

by Jekka McVicar

This has been a better week despite the weather. The days are getting longer, the light levels are increasing, the sun has shone off and on and the seedlings are emerging.

Nasturtium seedlingsThis has been a better week despite the weather. The days are getting longer, the light levels are increasing, the sun has shone off and on and the seedlings are emerging.

Our nasturtium seedlings will be beautiful flowering plants at the Chelsea Flower Show. They have been grown without extra heat and no extra light in a greenhouse where the temperature does not drop below 4°C at night. This temperature protects from frost but does not force growth. Another good tip for those that want to bring annuals into flower is to be mean and only feed the plants when changing the pot size; this way the plant won't produce too much foliage.

 French parsley seedlings and plant labelFor the Herb Farm we have been sowing French parsley. The trick to get a good germination is to sow the seeds on the surface of the compost and cover with perlite, the white granular material that can be purchased at most garden centres. Then put the seed tray or module tray in a propagator or on a heated mat at 16°C. The seeds will germinate in about 20 days, depending on light levels. It's the constant temperature plus good light that encourages germination. The seedlings are growing in modular trays; this is a brilliant method that allows for easy transplanting into the garden as soon as the soil warms up. As the roots have minimum disturbance the plants are not stressed and the crops get a good kick start.

Blue tit at bird feederThis is a wonderful time of year, everything is emerging after the winter and the birds are certainly feeding and singing. Our land here is surrounded by woods and hedges so we have a large population of birds. Blue tits are very beneficial for the gardener as they feed their young on caterpillars.

Talking of which, it is very easy to unwittingly overwinter caterpillars in glasshouses and polytunnels. Only the other day I found a large juicy green caterpillar trundling across some thyme plants in our multi-span polytunnel.

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Gardeners' World Web User 01/01/2008 at 00:00

Gardeners' World Web User 19/02/2008 at 09:22

how can you keep your greenhouse at 4 °C if you don't use any heat / and its -7 °C at your nursery?

Gardeners' World Web User 19/02/2008 at 11:22

I too would like to know the answer regarding the temperature inside an unheated greenhouse. I have just inherited a greenhouse and would like to know what the temperature is in a greenhouse without heating it? Is it the same as outside or higher?

Gardeners' World Web User 20/02/2008 at 07:45

Response to asparagus: For planting it is the crown and the roots that are the most important. Cut the new growth back to 8cm. Plant the crowns 45cm apart in a well prepared bed. For the next two seasons only remove 1-2 spears per plant. In the third season you can cut regularly until mid June.

Gardeners' World Web User 20/02/2008 at 08:16

Response to cook: The glasshouse is heated to 4 °C which at that temperature only protects the plants from frost it does not encourage new growth. And yes our lowest temperature recorded in the last few weeks has been -6 °C. Which to be honest has been great as it is clearing up all the bugs and pests we have wintered.

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