It's time to power down our greenhouses

Amid growing climate chaos, can we really afford, financially, ecologically, or morally, to be sowing tomato seeds in early February, just so we can pick fruits in June, asks John Walker

• This is an edited extract from John's new book Digging Deep in the Garden: Book One.

For the youngest to the oldest gardener, the novice to the expert, one captivating, enduring and miraculous activity shines out: growing plants from seed. When you stop to ponder how those piles of pumpkins, heavy bunches of carrots, or basketfuls of ripe tomatoes all start out as seeds, the realisation is humbling. When we sow seeds, the worst we can expect if things go wrong and the seeds fail to germinate is disappointment. We can try again and hope for better luck, but life goes on. In some parts of the world, if seeds fail to germinate, or crops fail to establish, those that sowed them could face death. If their seeds don't come up, they don't nip to the garden centre for another packet - they start living on food aid.