How to save your own tomato seed

Clearing out the greenhouse is a bittersweet moment.

It has me looking back wistfully over the season just passed, with all its highs and lows. I remember the massive crop of fat purple garlic cloves I harvested in July (yes, grown inside the greenhouse), the best I’ve ever grown; but I also wince at the memory of the battle I fought against blight, which got into my greenhouse with the rain after I thoughtlessly left a window open.

At the same time, though, there’s a palpable feeling of new adventures to come. Yesterday’s plants are making way for tomorrow’s delights: the moment the canes and spent plants were out the door I was busy refilling the borders with excitingly spicy winter salads. This year it’s mizuna, ‘Winter Density’ and bronze-leaved ‘Bughatti’ lettuces, plus winter purslane, coriander, spinach and chard. In fact I think I’ve overdone it a bit: there’s no way I’ll cram it all in to my two little greenhouses, so the overflow will go outside to take their chances in the open garden. Either way, I’m looking forward to bowlfuls of fresh salads till spring.

The last ripe tomatoes cling to the vines still, but that gives me another little lift of optimism as it’s my cue to get next year’s seed into store with all the promise of a new and hopefully blight-free tomato summer next year.

Save your own seed and you get your favourites back again next year for free. You help out the planet a little too: home-saved seed comes packaging-free, and with zero seed miles. You also know the plant they came from was grown organically and in peat-free compost.

You’ll find lots of extremely complicated methods for saving tomato seed out there, most involving fermenting the seed and skimming off the pulp…. Well, life’s too short for all that faffing about, so I don’t bother. All you really need is a ripe tomato, a teaspoon and a bit of kitchen towel. Here’s how:

Step 1: Pick your tomato

Choose your star tomato variety, the one you want to grow again next year, and select the ripest tomato you can find – it should be almost dropping off the plant.

Step 2: Prepare your kitchen towel

Bring your tomato into the kitchen and find yourself a nice sharp knife. Take a square of kitchen towel and fold it in half, then lay it on a plate, or in a takeaway tray – anything that’s flat will do.

Step 3: Cut your tomato in half

It doesn’t really matter which way you do it – top to bottom is fine, but I prefer across the girth as it makes it easier to scoop out the pith.

Step 4: Scoop out the pith

Use a teaspoon to scoop out all the pith and seeds you can get hold of. Some varieties don’t have much seed, or are quite dry (this happens a lot with plum tomatoes) – just remove what you can.

Step 5: Spread it over the kitchen towel

Use your teaspoon to spread the jelly-like pith with its seeds all over the kitchen towel. Try to space the seeds evenly – about 1cm between each seed – moving them about with the back of the spoon.

Step 6: Leave to dry

Place the kitchen towel on a sunny windowsill for about two weeks until it’s thoroughly dry. The pith will pretty much disappear, leaving the seeds attached to the kitchen towel.

Step 7: Store the seed

There’s no need to remove the seeds from the kitchen towel: just pop the kitchen towel seeds and all into a paper envelope, labelled with the variety and date. Store somewhere cool and dry.

Step 8: Sow your seed

Next spring, fill a half-sized seed tray with seed compost (you can use a takeaway tray too – just punch some holes in the bottom for drainage). Lay the kitchen towel with its attached tomato seeds on top. Cover with more compost, water well and pop into a propagator or onto a sunny windowsill: within about two weeks you should have a little forest of tiny tomato seedlings ready to take on the season ahead.