The other day I met a lovely local horticulturist who is growing and selling vegetables just outside Abergavenny. Claudia was keen to save some of her Italian heirloom tomatoes – her dad is Italian – and although I explain how to save tomato seed on the website I thought it might help to go through the process briefly with some illustrations. First harvest your ripe tomatoes and then let them ripen a little more somewhere warm and sunny. I then blanche large fruit and skin them before cutting them in half and scooping out the pulp with the seed in it. Using a spatula press as much of the pulp as you can through a fine sieve. This pulp and the skinned tomatoes can then be used for cooking or to make passata. When your seeds looks a bit like this put them into a jar filled with cold water. It is important to do this as the seeds are covered in a membrane which inhibits germination. Leaving the seeds in water for two or three days causes the membrane to ferment and break down so that when you empty the contents into a sieve and rinse thoroughly you have nice clean seeds to dry. Now spread your seeds out thinly onto grease-proof paper – not tissue paper – and put somewhere warm and dry like a window sill but not in direct sunlight. The seeds must not need to be warmed up! They will dry perfectly well at room temperature. After a day scrape the seeds around a bit to turn them over and leave to dry for at least a week.Scrape the seeds off the grease-proof paper, rub them between your fingers to separate them and when they feel completely dry put them in an airtight jar or container and keep somewhere cool – ideally a fridge – until you are ready to sow them. To get your seeds really dry so they will keep for years it is worth putting them in a container with some silica gel which changes colour when it has taken up moisture. You can also use dry rice as a means to further dry your seeds but, again, it helps to includes some silica gel as an indicator.