This is the best type of fertiliser for ripening tomatoes – it'll help you grow your best toms ever

Looking for the best fertiliser for ripening tomatoes? To find out which fertilisers are best at helping tomatoes ripen, I spoke to a few garden experts – and picked up some product recommendations along the way.

If you’re wondering why your tomatoes aren’t turning red, some plant food can give your fruit the boost they need – but to support their journey to better fruiting, you’ll need to look for the right ingredients.

If you’re looking for the best fertiliser for ripening tomatoes, you’ll need to keep a close eye on one ingredient in particular: potassium.

'If you want to give your fruit a helping hand, go for a fertiliser that’s rich in potassium,’ says Nick Wood, horticulturist at GardeningExpress.co.uk. ‘This encourages healthy fruit development by helping the plant focus its energy on ripening, rather than just growing more leaves.'

It's more about supporting the fruiting process as a whole, which is why fertiliser is one of the most important steps in learning how to grow tomatoes successfully.

'It won’t exactly speed things up, but it makes sure the plant has the right nutrients to support the process naturally,' Nick adds.

To find a tomato fertiliser with the right levels of potassium, check the label for NPK. You might have noticed it before, but if you haven’t decoded it, N stands for nitrogen, P stands for phosphorus, and K stands for potassium.

Go for a product with higher K (potassium), and lower nitrogen (N), for the best results. Of course, you could make your own tomato fertiliser, but you'll need to include potassium-rich ingredients like banana peel.

I wanted to find some more product-specific recommendations, so I asked Nick for a few of his top picks.

‘Tomato-specific fertilisers like Tomorite Tomato Feed have the ideal ratio of nutrients for healthy fruiting, and this one includes added seaweed extract to help your tomatoes grow ripe and juicy,’ he says.

‘Other multi-purpose fertilisers like Levington Seaweed Tonic and Miracle-Gro Plant Food are also great options for feeding tomatoes, as they’re hungry plants that benefit from regular, nutrient-rich feeding throughout the growing season.’

It’s not all about the fertiliser, though – a healthy, balanced soil can go a long way to helping tomatoes ripen into red fruits, too.

‘A successful garden starts with healthy soil,’ says Mark Sage, B&Q’s outdoor expert. ‘You can help ensure that your garden thrives with compost or organic fertilisers that will give your vegetables and herbs the nutrients they need for robust growth.

‘Consider your crop’s needs here, too: tomatoes will do best when given some extra compost.’

Mark recommends the Verve Peat-Free Multipurpose Compost from B&Q as a great starting point for tomatoes.

So, when it comes to finding the best fertiliser for ripening tomatoes, look for a product that's high in potassium and low in nitrogen to support your plant's fruiting process. It'll help you grow your tastiest tomatoes yet!