Grow amazing tomatoes outside in the UK

Want to grow amazing tomatoes outside in the uk, or any other temperate short season climate? Here I’m going to tell you that not only can you grow tomatoes outside in the UK, but you can do it really well. It’s a well perpetuated myth in the UK that to grow tomatoes well we must have a greenhouse. Now we’re also being pushed to have poly-tunnels too. But what if you don’t have the finances, space, or it would be a target for vandalism? Well, I don’t have a greenhouse, and I never have had one. I grow all my tomatoes outside. All we need to do is plan ahead, and take a little more care.

Choosing the right type, growing habit, and variety

Choosing the right type, growing habit, and variety for your space, and growing season length is vital for growing tomatoes outside in the UK. So what are we looking for? When we think of tomatoes, we generally think in terms of the Cherry, Saladette, smaller Ox hearts, and large Beefsteaks. Then there is the growing habit of these plants too. Tomatoes are a part of the nightshade family, and they are either determinate, or indeterminate in growing habit.

Determinate Tomatoes

Determinate means they are generally smaller in size. These range from the micro-dwarf, such as the Mini-Marzano from Brad Gates, to the Dwarf that stands around a metre. This family are a bush type that do not need pruning, and set most of their fruit at once. In the past some of these varieties were not known for being great in flavour, but rather early production. However, in more recent decades breeders such as Brad Gates of Wild Boar Farms, and the Dwarf Project have made great strides in producing varieties that hit all the tick boxes. The advantages of growing dwarf varieties is that they are great for containers, no pruning, tend to have much shorter maturity dates, can stagger the season, usually have a shorter day-to-maturity date at 65-75 days, and fit in tiny spaces, or hanging baskets. Disadvantage is that they can take up a lot of space in a small bed, and can be difficult to get around in certain spaces. Size of beefsteaks tends to be limited.

Indeterminate Tomatoes

Indeterminate tomatoes are vines. Whilst they still have a bushing habit that wants to creep across the ground taking over the world, this is not the best way to grow them in our garden. It’s better to grow them upwards using canes, and prune down to a single leading stem. The plant will then set trusses of fruit in continuation from the ground up. Unlike the Determinate plants, Indeterminate plants just keep growing and setting fruit until the first frost, or we stop them. The advantages of growing indeterminate tomatoes is that you can grow them against a wall in grow bags, at the end of your beds, in containers with support, there is more choice of them in the UK, and with pruning they may take up less square footage in your beds. Disadvantages are that they do need constantly attaching to the supports, may take more feed and watering to produce larger healthy plants that fruit well, larger beefsteak plants have a longer days-to-maturity date from 90-120 days.

The right variety

Choosing the right variety is important if we want to grow tomatoes outside in the UK too. Because if like me you live in a high risk Blight area, you’ll want a variety that is short season, and Late Blight resistant. Late Blight spreads on the wind, so in good years we can get away with not getting it at all. Being in local gardening groups also helps us know when it’s on its way, so that we can get our harvest in early too. However, none of that matters if you’ve chosen a variety that you just don’t like. I’ve lost count of how many different varieties I’ve grown now, and I’ve certainly grown some I do not like. Our number one on the list right now though is Barry’s Crazy Cherry from Brad Gates at Wild Boar Farms in the US. I like that a lot of his varieties have proven Blight resistant, are prolific, taste great, and I can save seed from them.

Getting ahead of the short season.

Once we’ve chosen our seed, we need to get them started, and the timing for this is important. You need to know your growing zone, and your last predicted frost date. I’m in temperate zone 8, with a last frost date of mid May. Find yourself a good long range weather forecast for your area, and start keeping a track of it for a month ahead, so you get to know how reliable it is. It’s best to start your tomatoes 8-6 weeks before your last frost date. You could start earlier, but because they are going outside there are reasons you may not want to. We’ll discuss these later. There are two sowing methods commonly used-

Multi-Sowing

This method is where we place all our seed in a relatively small growing space, and wait for them to germinate. Once the first leaves, cotyledons, are though we then prick these out into a pot of their own. I have a separate post about this HERE.

Module Cell Sowing

This is sowing into single cell seed trays that have enough room for our seedlings to spend some time in them getting established before potting on. I prefer this method for all my plants that I grow outside. This is because each time we transplant our little plant goes into shock, and takes time to settle to start growing again. I want to do this as little as possible. From my single cell seed trays I will pot on into 4 inch pots, and from there my plants will grow on until ready to transplant outside.

Growing medium

Over the years I’ve used all sorts to start my seeds in. It’s a fact that commercial compost in general used to be much better made than it is now. Seed starting compost can sometimes have nothing in it, so if your seeds start to fail it’s because they’ve run out of food reserves. I prefer to use either a mix of my own, with worm casting from my own wormery, or a general purpose mix. You may have to sift the latter as they are not as finely graded as they used to be. You can also use a cactus mix to start off seedlings, as this is free draining. Don’t use something that holds too much water, as this will cause damping off.

Feeding

With a good compost, and good light from either South facing windows, or grow lights if you invest in them, your young plants shouldn’t need feeding. If you end up needing to keep them in longer due to bad weather, then a weak broad spectrum liquid feed should be enough.

Preparing to grow on outside

Preparation for transplanting your young warm weather plants outside is a must. Having watched your forecast you’ll have a good idea when to start. You’re looking for a good two weeks of consistent good weather with no signs of frost. This can be done using a cold frame, or just a table. Taking the plants outside for a small amount of time a day, and not during the hottest part. We’re allowing the plants to become accustomed to the wind, temperature changes, and full sun. If we don’t the fragile leaves will suffer wind and sun burn. Have something on hand to cover your plants just in case a cold front does move in. It can be as simple as a sheet to cover them for the night.

I’m actually going to talk about what I do when I transplant my tomatoes in a separate in depth post.

Recommended seed companies

I am in no way affiliated to any of these companies, they are just companies I have, or do use to buy tomato seeds. Unfortunately those outside the UK no longer ship to us.

You can see the video for this one here-