My grandfather grew tomatoes in the greenhouse. My father grew tomatoes in the greenhouse. So I’ve grown tomatoes in the greenhouse.
Are home-grown tomatoes off the menu if you have no greenhouse?
Here I describe my experiment with outdoor growing in the summer of 2019 and give my top variety to try.
The post contains a useful Youtube clip on how to cordon your tomatoes.
Glasshouse vs outdoor growing in the UK
If the tomato were a person – I imagine a sun-kissed Italian basking in the kitchen garden with a glass of Chainti. Sun loving and revelling in life outdoors.
But the UK climate is not Italian. We have fewer sunshine hours and lower light levels and a shorter growing season than the Med.
There are therefore certain advantages to growing tomatoes under glass in the UK. Long hot summers are not guaranteed so the energy amplification of glass and the extended growing season are so useful. Greenhouse grown tomatoes are also less susceptible to blight than those grown outside.
Watering is an important consideration. On a sunny day in summer I will water my greenhouse tomatoes twice a day. Admittedly, they are container grown but regular watering is important to ensure good growth and prevent poor ripening. Outside, especially in good soil, less frequent watering will be required as the plant will lose less moisture to the atmosphere than in a hothouse.
Many people who want to grow tomatoes just don’t have a greenhouse of course. They’re an expensive investment, unsuitable for the smaller garden and impossible on a roof terrace or balcony.
The good news is that it is possible to grow good tomatoes outside in the UK. Admittedly, a grey wet summer – such as the one we had in 2012 – will reduce the productivity but you will still get a crop. A summer like the one we had in 2018 was perfect for tomatoes outdoors so long as you were on top of the watering.
Let’s go outside – where will you grow your tomatoes?
The first thing to think about when growing tomatoes outside is how much room you have to grow tomatoes in. There is a tomato variety out there for any sized garden, be it a tumbling cherry variety for a window box or neat rows at an allotment. What space do you have and how much of it do you want to devote to tomatoes?
It’s also worth considering aspect. A sunny south facing spot against a wall or fence will be the next best thing to a greenhouse. A cold north-facing roof terrace will be a less safe bet as it will barely see the sun. Think of the sunniest spot in your garden and consider if you can squeeze a tomato plant in. If it’s a patio then you could consider a variety suitable for a pot. If it’s a shrub border – could you countenance a tomato plant nestled amongst the bushes?
When you’ve chosen your site, think also about the soil. Tomatoes are hungry feeders so a good soil, enriched with compost will get your tomatoes off to a good start.
Think also about water. Tomatoes need allot of water. Tomatoes planted in a corner of the garden distant from a tap or water butt will be less likely to be watered regularly than a pot by the back door.
Finally think about what type of tomatoes you like to eat. Do you like a big variety to slice in a cheese and tomato sandwich, or do you like little cherry varieties to pop in your mouth as you sit in the garden? Do you want a heavy cropper where lots of fruit will be ready at the same time to make a delicious soup or would you rather pick a handful a week for use in a variety of dishes?
Bush Vs Cordon varieties
When you look on the websites of seed suppliers or read the packets in a shop or garden centre you may see tomato varieties described as ‘Cordon’ or ‘Bush’ and also ‘Determinate’ or ‘Indeterminate’. They may initially confuse a new grower, but understanding what they mean will help you in choosing your varieties and in how to care for them when they are growing.
Determinate or bush tomatoes, grow in a loose or bushy shape and don’t need training, although they may need some support if they get leggy. They usually grow to a compact height – thigh or waist level at a push and they stop growing when fruit sets on the top bud. Most determinates are well suited to growing in a container on a patio. You will find the fruit on most bush varieties ripen within a couple of weeks rather than continually setting and fruiting throughout the season.
Indeterminate or cordon varieties should continually grow and produce fruit until the end of the growing season in late autumn. They can grow tall so it is common to stop their growth at a supportable height and allow 5 or 6 side trusses to develop, grow and ripen. Because they grow tall they require careful staking. Side shoots will need to be removed to train the cordon.
A word about Blight
Generally, I find that plants grown outside are less susceptible to diseases than greenhouse ones. Getting the atmosphere in a greenhouse right in all weathers can be problematic. Once a pest or disease gets into your greenhouse it can spread easily from plant to plant.
A devastating disease called blight is, however, more likely outdoors. It thrives in damp environments so will be more prevalent in cooler wet summers. Once it takes hold it can destroy your tomato plants. The first signs of blight are dark brown patches at the edge of the leaves. The area affected expands until the leaves are killed and stems become affected too.
No foolproof treatment exists for blight but technology is helpful in the form of the Met Office’s blightwatch website which tracks its spread each year. When you know it’s coming you can minimise its impact by making sure your plants have good air circulation, trimming off excess leaves and stems to expose the fruiting trusses to good air flow. Some growers even advocate taking every leaf off a plant when blight is in the air as the fruits can ripen regardless.
Far and away the best protection against blight is to choose blight resistant varieties. Fortunately seed growers have developed more blight tolerant varieties and growers have trialled various types in the UK climate to discover outdoor winners.
I’ve researched websites, seed catalogues and asked around in the gardening community to discover the best ones to suggest to my readers. They are summarised in the table below. If you can’t read it well, click on the image and it will open larger.
Not all seeds are available from every supplier so shop around and check a few online suppliers.
I’ll be trialling 4 varieties in my own garden – outside- in 2019. I’ll be sharing further information on seed sowing, planting out, training and support throughout the season.
June 2019 Update – How are my outdoor toms faring?
All four varieties sown back in March are doing very well. I chose to grow Lizzano (Determinate/bush variety) and Fandango, Outdoor Girl and Gardener’s Delight as cordons (indeterminate). Outdoor Girl was not suggested to me by fellow gardeners but was an impulse buy based in its name.
I started them off in seed trays indoors, potting on in april and then planting out in the garden in late May. A few cold nights and threatened late frosts meant I did wait until almost June to plant them out and they were a bit pot bound and sickly, in need of root space and sustenance by the time I planted them out. They soon greened up and started growing very well.
The three cordon varieties are about 70 cm tall and trained either up canes or up string cordons on crossed hazel canes, a method I saw last year at Barnsdale Gardens. If you want to know more about training tomatoes as cordons I’ve done a You tube clip, which you can see below.
I’ve been keeping an eye on Blightwatch as after a warm and dry early summer, June turned very wet. At least one day had a high blight warning but the warmth and sun has returned and so far there are no obvious sign of blight.
Autumn 2019 update – Post season analysis
My experiment was a success and I will definitely grow tomatoes outdoors again. I am aware that in a wetter summer the results could have been very much worse but the cost was just over £10 for four seed packets and I was rewarded with huge numbers of fruits. My favourite variety was ‘Outdoor Girl’ and I will just grow this variety next year. These seeds cost around £3 a packet.
There were many days when Blightwatch alerts appeared on my mobile phone and the frequency of these increased as the season progressed.
Despite this, and despite the fact that blight did eventually affect all my tomato plants, I still got an excellent crop. By the end of the season I had more tomatoes than I knew what to do with and ended up making soups and pasta sauces to freeze.
Here’s how I found my four chosen varieties performed.
- Lizzano was a very heavy cropping cherry but succumbed quickly when blight took hold. A bush variety so it couldn’t be cordened to increase airflow. As blight took over I harvested the fruits all at once and filled the base of a large washing basket.
- Fandango was a very large, tasty and attractive variety. Good for slicing in sandwiches but not the heaviest cropper per truss. Blight took hold before all fruits ripened.
- Gardeners’ Delight – Cropped well with tasty medium sized fruit. Blight did affect it but not before most of fruits had ripened
- Outdoor Girl – My top variety – heavy crops of useful and tasty middle sized fruits. Blight took longer to take hold and most harvested before it did so.
Happy growing and do let me know if you’ve any comments on tomato growing.