Tomatoes are a kitchen favourite and many of us have attempted to or have successfully managed to grow our very own tomatoes at home. Tomatoes are however, not the easiest fruits to grow and become even more complex if we choose to grow them outdoors. In the UK tomatoes grown outdoors will require adequate shelter and protection from the elements; however tomatoes grown outside are considered to carry a much better flavour than those grown inside many gardeners consider them to be worth the extra effort.
Before setting out to grow tomatoes outdoors you should pay careful attention to the type and variety of tomato you wish to grow as some varieties are simply not suitable for growing outside where as others suit containers or pots for gardeners who have limited space. The soil should be humus-rich and well-drained and well prepared long before planting.
If you are starting your tomatoes from seed then you will need to sow them under glass in late March or early April in order to harden them off during May ready for plating outside in late May or early June. If you're planning on growing your tomatoes under cloches then mid-May will be fine providing the weather looks promising. All being well and providing the UK receives average weather conditions for this time of year your tomatoes will be ready for harvesting around the middle of August.
Soil Facts
To be able to grow tomatoes outdoors you need to ensure you have a warm space in your garden available in which to plant them. Ideally in front of a south facing wall but any position that is sunny and not too exposed should be sufficient. During the winter months prior to planting your tomatoes you should work some garden compost and peat into the soil and apply some fertilizer just before planting.
The number of tomato plants you intend to grow is also a factor as if you only need to grow a few plants then you may find planting in pots, containers or specialised tomato planters easier to manage. These pots can be positioned on balconies or patios but if opting for this method you must remember to water and feed your plants more frequently.
Sowing and Planting
The instructions for growing tomato seedlings can be found in our 'How to Grow Tomatoes in the Greenhouse' guide by clicking here. However, if this is your first time growing tomatoes then you may want to consider buying seedlings from a reputable supplier or online garden centre. These seedlings will arrive ready for planting out so ensure to check that they are healthy. Look for dark green, sturdy seedlings which are at least 8 inches tall. Be ready to plant out your seedlings into pots, containers or upside down grow bags when the flowers on the first trusses open, remembering to water the plants thoroughly before planting.
Looking after the crop
Looking after your tomato crop throughout the growing cycle will differ depending on the type of tomatoes you are growing. Cordon varieties will need to be staked or tied to a cane at 12in intervals as the plants grow. Any side shoots that appear will need to be cut or pinched out when they are about 1inch long. Like with indoor tomatoes you will need to ensure that the soil is kept moist at all times as irregular or sporadic watering may lead to the contraction of blossom end rot or fruit splitting, two ailments your tomatoes could do without.
Harvesting
Like when grown indoors in a greenhouse tomatoes that are grown outside will be ripe and fully coloured when they are ready for harvesting. Again you should hold the tomato in your palm and with your thumb break of the fruit at the knuckle (swelling within the flower stalk).
Outdoor Tomato Varieties
Outdoor tomatoes are typically classified into 2 groups; Cordon varieties and Bush varieties.
Cordon Varieties
Cordon varieties are single stem varieties and have to be trimmed and supported. The stem should be stopped after the 4th truss has set to hasten ripening before the autumn frosts. Some popular Cordon varieties include:
- Ailsa Craig - produces bright medium-sized fruits that mature early and are a tomato accredited for their full flavour.
- Golden Sunrise - typical choice for anyone wanting yellow tomatoes, Golden Sunrise tomatoes are medium-sized and have a distinctive taste.
- Tumbler (Tumbling Tom) - this variety of tomatoes can be grown in a pot or in a hanging basket.
- Tigerella - these early maturing tomatoes are very distinctive thanks to their red and yellow stripes when mature.
- Gardeners Delight - a favourite with more experienced gardeners, the Gardeners Delight gives bite-sized tomatoes with a tangy flavour and is best grown outdoors.
- Saint Pierre - A large, irregular shaped tomato that is deep red in colour and produces high yields.
Gemini - medium-sized and sweet tomato that does well in cooler summers.
Bush Varieties
These varieties are much easier to grow tomatoes outdoors; they are either bushes 1-2ft high or creeping plants less than 9 inches tall. They require trimming, supporting or stopping.
Pests and Diseases
Tomatoes are highly susceptible to attack from a large number of diseases and pests with disease being most prevalent. However, tomatoes that are grown outside are far less likely to suffer than those grown inside. By paying careful attention to your tomato plants as they grow you should be able to spot the warning signs early on and catch diseases before they have a chance to set in on your tomato crop. Some of the most common diseases known to plague tomato plants include:
- Greenback - Common symptoms of Greenback include the area around the stalk hardening and remaining green and unripe. The two main causes include lack of potash or too much sunlight and there is no treatment available. Steps to avoid Greenback include the provision of good ventilation and regular application of potash-rich fertilizer.
- Split Fruit - A very common complaint in tomatoes grown both under glass and outdoors. Typically caused by heavy rain or watering after the soil around the root has dried out. The sudden increase in size causes the fruits skin to split. Again there is no treatment available but ensuring roots are kept moist is a good way to avoid it.
- Hollow Fruit - Caused by poor pollination conditions (air too hot, too cold or too dry) or too much potash. There is no treatment but by trying to avoid the above your crop should be fine.
- Virus - There are several viruses that are common in tomatoes but typical symptoms include mottled leaves, curled stems which have dark vertical streaks or thin and distorted foliage. Fruit of infected plants is often mottled and bronzed. Unfortunately there is no proven cure for infected plants and affected plants should be destroyed. In order to prevent viruses try to buy virus-free plants from reputable suppliers, don't handle after smoking and spray to control greenfly.
- Tomato Leaf Mould - Evidence your plants are suffering from Tomato Leaf Mould include purplish brown mould patches on the underside of the leaves with the upper side of the leaf having yellow coloured patches. This can be treated by removing lower leaves and spraying the plant with mancozeb as soon as the disease is identified.
- Greenhouse Whitefly - For plants that are grown indoors Greenhouse Whitefly are likely to be the most common threat. The adult fly and their larvae feed off the plants until they become pale and curled and the foliage is left sticky with black mould growing on the honeydew. There is no easy way to get rid of these pests but spraying with bifenthrin regularly until the plants are cleared should work adequately. An alternative method is to hang fly catcher strips above your plants.
For more information or to order tomato seeds from one of the UK's leading online garden centre visit Plant Me Now at www.plantmenow.co.uk.
