Eden horticulturalist Duana Pearson shares her top tips on how to grow tomatoes outside, when you don’t have the luxury of a greenhouse – including planting from them seed, treating tomato blight, and making your own tomato feed using comfrey leaves.
There really is nothing better than home grown tomatoes. Great news for those with greenhouses, but what about the rest of us? Well here at Eden we grow plenty of tomatoes outside, sometimes with fruit still ripening into November.
With a sunny spot in your garden, space for some pots or a grow bag and a minimum temperature of 10 degrees Celsius, you can grow tomatoes too.
Which tomatoes to grow
Did you know, that when tomatoes (Solanum lycopersicum) were introduced to Britain in the 16th century from their native South America, they were branded inedible because of their close resemblance to the toxic, deadly nightshade? Since then, all sorts of gorgeous-tasting varieties have been cultivated…
When choosing a tomato variety, go for one that’s not only blight-resistant, but suitable for the spot it’s to grow in. For taller growing (cordon) varieties, try Gardener’s Delight, Chadwick Cherry, Money Maker, Sweet Olive, or Alicante.
For pots or hanging baskets, try bush or tumbling varieties such as Tumbling Tom, Garden Pearl, or Tumbler.
You might even consider heritage or organic varieties, tomatillos (golf-ball-sized fruits surrounded by a papery husk, which have a tart flavour and are a staple of Mexican cuisine), or beefsteaks – great for cooking – and showing off!
How to grow tomatoes
If you’ve time to grow them from seed…
- Sow the seeds indoors in March or April.
- Keep your seedlings moist and in a sunny position.
- Plant out, two feet apart, in a sunny spot after risk of frost has passed. For example, in June.
Once your tomato plants are in the soil…
- Cordon varieties (as opposed to tumbling or bush plants) need staking well. Keep tying in as the plants grow.
- Taller growing tomato plants also require you to pinch out side shoots carefully to create one strong main stem and encourage fruiting. Side shoots are the growths that appear where the main leaves join the stem. Try to limit the plant to four to five trusses, then pinch the tip of the side shoot. This will probably give a height of about five feet. This will encourage the plant to put energy into ripening fruits, and should still give you a good yield.
- Feed when fruits start appearing. Many tomato feeds are widely available – or you could make your own using comfrey leaves (recipe below).
- Harvest from July, as the fruits turn red.
Duana’s top tips
- Even watering, little and often, will help prevent fruit from splitting.
- Plant tomatoes with basil for a delicious combination. It’s also said to improve the flavour of the tomatoes as they grow.
- We use homemade comfrey tea to feed our tomatoes. To make this, top up one full bucket of comfrey with water and leave to steep for a few days. Or you can leave it for longer and then dilute the ‘tea’ with water. Sieve it out and apply neat with a watering can. This is best done the same day you water the tomato plants.
- If you get to October or November and still have fruits on your tomato plants that don’t look like they are going to ripen, harvest them all and make green tomato chutney.
Dealing with tomato blight
Blight, Phytophthora infestans, is probably the biggest concern when growing tomatoes. Spores can survive in infected seeds or be blown in from miles away, but will only affect a plant if landing on wet foliage or fruit. It starts as ugly, brown blotches on leaves, but can quickly spread to fruit and other plants.
- Pick resistant varieties – but be aware this may only delay any infection.
- Use a reputable supplier and don’t save seed from infected plants.
- Change where you put plants in the Solanaceae family (including aubergines, potatoes, peppers and petunias) every few years. This is known as ‘crop rotation’.
- Allow good air movement around plants. You can do this by spacing them well apart, staking well, and removing side and old shoots.
- When watering, try to water in the morning. Make sure you water only the soil, rather than the foliage itself.
- In early stages of a blight infection, remove diseased leaves.
- Use copper sulphate solution to help protect healthy foliage.
- Sign up to the free Blight Watch service, which sends alerts about blight-risk periods, based on temperature and humidity.
On the vegetable plot at Eden
We planted our tomatoes out last month. They’re growing down in the garden by the Bakery, and we’ll be passing some of them on to the chefs. We’re also busy tackling sawfly on our currants and gooseberries – using foxglove tea!
If you’d like to learn more about gardening from Eden horticulturalists, join us for one of our one-day gardening courses – or do all eight and get a qualification!
Thanks to Poppy/hddod for the photo.