It’s true that growing tomatoes outdoors poses some challenges, but it’s not the impossible task some gardeners might have you believe. We’ve been gardening all of our lives at TGH, and it’s only in the last couple of years that we got our first greenhouse. Until then, all of our tomato plants were grown outside.
Outdoor tomatoes can be just as prolific as indoor tomatoes, and in this article, we’re going to share a lifetime of tips and tricks to help you avoid the dreaded tomato blight, and to increase productivity.
How to grow tomatoes outdoors
Tomatoes need light, heat, water and ventilation. While light and heat can be hard to provide in temperature climates, ventilation and water are in abundant supply. So right from the start, there are advantages to growing tomatoes outdoors.
We’ve got a comprehensive list of tips for growing tomatoes outdoors in this article, but choosing the best tomatoes to grow outdoors is just as important.
Tomatoes are subtropical plants. They originate from Peru and Bolivia and grow naturally in free draining, warm, humid, conditions. The tomatoes we grow today are bred to cope with cooler temperatures, slower drainage, and less sunlight. As we’ll explore below, there are some exceptionally reliable tomato varieties to grow outdoors.
The 10 best tomato varieties to grow outdoors in cool climates
As a rule, fast-cropping tomatoes are easier to grow outdoors. They have a shorter growing season, so make the most of our limited summer sun while they can. Cherry tomatoes are generally the fastest cropping varieties, but don’t let that limit you. There are plenty of fast cropping salad, beefsteak and plum tomatoes too.
1. Gardener’s Delight
- Habit: Vining
- Disease resistance: None
- Pest resistance: Good
- Type: Salad
- Early ripening: 65 days
Gardener’s Delight is the most widely grown tomato in the world. It grows happily indoors, under glass, and outdoors, and while it has no specific resistance to disease it grows well in most climates and rarely suffers infection as the stems don’t usually attract pests.
2. Ferline
- Habit: Vining
- Disease resistance: Verticillium wilt, fusarium wilt
- Pest resistance: None
- Type: Salad
- Early ripening: 65 days
Ferline are great tomatoes to grow outdoors, with a good level of disease resistance and a reliable habit of ripening at least two weeks before most other varieties. Ferline are vining tomatoes so with correct pruning for ventilation will thrive outdoors in a reasonably sunny spot.
3. Patio Plum
- Habit: Determinate
- Disease resistance: Good general resistance
- Pest resistance: Excellent
- Type: Plum
- Early ripening: 75-80 days
Patio plum is perfect for gardeners with limited space. These dwarf tomato plants have sturdy stems and thick foliage. The short internodes between leaves maximize photosynthesis without shadowing the fruit and water won’t stand on the leaves either. Patio Plum isn’t bred for disease resistance, but its foliage and stature make it resilient against pests, blight, and mosaic virus.
4. Ailsa Craig
- Habit: Vining
- Disease resistance: Good general resistance
- Pest resistance: None
- Type: Salad
- Early ripening: 90 days
Ailsa Craig is a gorgeous salad tomato, with good general disease resistance. With the right supports and good pruning, it will usually bear fruit later in the season than most, providing a good late summer crop for outdoor gardeners.
5. Indigo Rose
- Habit: Vining
- Disease resistance: Good general resistance
- Pest resistance: Good
- Type: Cherry
- Early ripening: 80-90 days
Indigo rose is one of the sweetest tomatoes you can grow outdoors. Their black skins are intensely dark even before they ripen, eventually producing gradated fruits from deep black to rich red at the base. As vining cherry tomatoes they are also easier to manage in gardens where fungal pathogens already exist.
6. Black Cherry
- Habit: Vining
- Disease resistance: Good general resistance
- Pest resistance: Good
- Type: Cherry
- Early ripening: 65 days
So many colored cherry tomatoes hold all their pigmentation on their skins, with red flesh inside. Not Black Cherry. Black Cherry tomatoes have deep purple skins and pastier flesh than most cherries, making them ideal for sauces and salads, and anything in between. While Black Cherry tomatoes have no specific disease resistance, we have never had any problems with blight, even when their neighboring plans have been overcome.
7. Banana Legs
- Habit: Determinate
- Disease resistance: None (particularly susceptible to blossom end rot)
- Pest resistance: Good
- Type: Plum
- Early ripening: 75 days
Banana Legs had a brief moment in the spotlight a few years ago. Sadly, their poor disease resistance has put many gardeners off growing them. However, we love their flavor (an especially umami tomato) so have persevered.
The key to growing banana legs outdoors is space. Give at least 1ft of breathing space around mature plants, and never, ever, wet their foliage. The fruits ripen much better outdoors and their flavor is outstanding.
8. Hundreds and Thousands
- Habit: Determinate
- Disease resistance: None, but fares well outdoors
- Pest resistance: Poor
- Type: Cherry
- Early ripening: 85 days
Forget hanging baskets filled with petunias, grow tomatoes instead. Hundreds and Thousands are a beautiful determinate tomato that grows exceptionally well in hanging baskets, with trailing vines and hundreds of tiny tomatoes. Growing them in window boxes or hanging baskets provides plenty of ventilation around their bushy forms.
9. Super Marmande
- Habit: Semi-determinate
- Disease resistance: Good general resistance
- Pest resistance: Good
- Type: Beefsteak
- Early ripening: 55 days
The pin-cushion beefsteak, Super Marmande is one of the few beefsteak tomatoes that will grow outdoors without developing blossom end rot. While feeding regularly is essential to prevent the frustrating fruit deformation, it is one of the largest tomato fruits you can grow outdoors in temperature climates.
10. Golden sunrise
- Habit: Vining
- Disease resistance: None
- Pest resistance: Good
- Type: Salad
- Early ripening: 80 days
Golden sunrise adds a lovely pop of color to any patio, with vividly orange flowers, and deep, rich, yellow-coloured fruits in the middle of summer. They grow well in containers with a single bamboo support, which also allows you to move them around the garden as the seasons change so they can get maximum sunlight.
15 tips for growing tomatoes outdoors
1. Choose a disease resistant variety
Disease resistance can be confusing, but hybrid tomatoes have specific resistances to early and/or late blight bred into them. Heirloom tomatoes may not state disease resistance on their packets but are usually reliable if pruned correctly.
2. Sow early
Sow tomatoes indoors early. Sowing tomatoes in late February can give you a great head start on the season, and means you can plant out into the garden or in containers as soon as the risk of frost has passed.
3. Harden off
If you’ve grown tomatoes from seed, harden them off slowly. Start by taking them outside for 2-3 hours in the early afternoon, then bring them in for the evening. After a couple of days of doing that, leave them outside from the early morning through to the early evening, as they get used to the sun’s patterns, and daily temperature drops.
4. Buy hardened-off seedlings
If you grow tomatoes from shop-bought seedlings, choose tomato seedlings that have been outdoors already. Tomato plants sold from nursery greenhouses still need hardening off. By buying plants that have lived outdoors in the nursery you know they are ready for planting out.
5. Plant in full sun with shelter from direct winds
Most outdoor tomatoes can cope with mild summers, but it’s still important to give them as much light and heat as you possibly can. Find the brightest spot in your garden, and place tomato plants somewhere with an absolute minimum of six hours of direct light per day.
If you have a sheltered spot by a wall in full sun, that’s even better as it will reduce the risk of fungal spores being carried on the wind.
6. Plant deeply
Even after hardening off, tomatoes grown from seed indoors will not be used to the wind. Remove the lowest leaves of your tomato plant and plant it as deep as possible. Aim to plant at twice the depth of the root ball. This provides anchorage against winds immediately, but also encourages roots to grow from the underground stem, and gives better access to ground water.
7. Space plants in neat rows, with generous spacing
Tomato plants grown outdoors will be rained on, that’s a given. So it’s impossible to keep their leaves dry at all times. This increases the chance of blight and mildew. When you plant your tomatoes, leave an extra foot between plants to allow for full air circulation around each plant so foliage can dry off after rain.
8. Companion planting
Companion planting might sound like hard work but it’s incredibly important for outdoor crops, either to distract or repel pests. Planting marigolds, basil or nasturtiums around the base of tomatoes helps to keep aphids at bay, while slugs will choose to eat marigolds or nasturtiums over tomatoes.
9. Tie vining tomatoes in to supports
Outdoor tomatoes are more likely to snap under their own weight. Outdoor vining tomatoes need tying in weekly to protect them from wind, but also their own weight. Rocking in the wind makes their stems thicker and stronger, so they are heavier plants by the end of the season.
10. Provide gentle support to determinate tomatoes
Determinate tomatoes shouldn’t be tied in to supports other than a single central bamboo, or a tomato cage around the entire plant. The idea of the limited support is that plants are allowed to rock, but it also helps to improve airflow around bush tomatoes which hold humidity more than vining varieties.
11. Feed more when flowers start
If you plant tomatoes indoors they will usually be in fresh compost or tomato grow bags. Outdoor tomatoes grow best in the ground, benefitting from the ground-water, and reducing the regularity of watering. This makes it super important to feed them more often when their flowers begin to form. The extra feed helps to boost foliage strength, encourages higher nectar production (for better pollination) and adds essential nutrients for healthy fruit.
12. Water regularly, and conscientiously
Because you are completely in charge, you can water indoor tomatoes like clockwork. Outdoor tomatoes aren’t like that. Outdoor tomatoes are watered by the rain as much as by you, so check the soil moisture before watering. Aim to water once every two days, but don’t water if the soil is already wet from rain.
13. Prune tomatoes properly
Dense foliage harbors bacteria and blight, it also puts more pressure on the roots to maintain foliage. Read our pruning guides for cherry tomatoes, determinate tomatoes and cordon tomatoes for detailed information on how and when to prune each type.
14. Check for pests regularly
Outdoor tomatoes are more likely to suffer from pest damage, and pests are a significant cause of disease. Check your plants regularly for caterpillars, moths, aphids and spider mites, as they can all cause significant damage in their own right while helping to spread disease.
The best time to check for most pests is during the day, but check for snails and slugs at night and remove them.
15. Prune foliage by half when fruit starts to ripen
Greenhouse tomatoes are ripened by heat as much as sunlight. Outdoor tomatoes rely almost entirely on direct sunlight to ripen. As fruit reaches its full size, remove 50% of the foliage from the plant. This gives sunlight access to fruit, and the direct light will heat up the skins and quickly break down the cells to begin ripening.
Conclusion
Growing tomatoes outdoors isn’t as hard as it sounds, but you do need to stick to the rules above to get the best crop possible and avoid common diseases. No matter how strict you are about keeping clean compost, or aerating your plants, there’s nothing you can do about wind-borne pathogens blown in from neighboring gardens.
So rather than worry about growing the perfect plants, just be rigorous and ruthless with pruning when things do go wrong, and make the most of short seasons by growing early cropping varieties.