Tomatoes have come on in leaps and bounds over the years and now we see multi-coloured tomatoes, attractively striped and spotted. They’ve been bred to withstand diseases, some you can grow outdoors and now there are grafted tomatoes, where the fruiting plants grow on robust roots for prolific growing.
Just read these helpful pointers to guide you in growing this popular and versatile salad vegetable.
When is the best time to start growing tomatoes?
Growing seeds outdoors - You can start sowing seeds from late March to early April.
Growing seeds in a greenhouse or indoors - You can start sowing seeds earlier, from late February to mid-March.
How to prepare your tomatoes for growing
When the time comes to start sowing the seeds you should:
- Sow seeds singularly into module trays or seed trays.
- Once the plant has germinated (second set of leaves has emerged) prick out into 9cm pots.
- When the plant is approx. 2 inches (5cm) high transfer them into grow bags, containers or in prepared soil outside.
- Plants for growing outdoors should be hardened off (the process of moving plants outdoors for a short period each day to get them used to the new conditions) first.
- Hold the plants by the leaves, avoiding touching the stem.
Keeping seeds at the perfect temperature
For germinating seeds ensure an ambient temperature of 18C (64F). As seedlings/ young plants grow ventilation is key and if growing indoors make sure plants are shaded to lessen the burning effects of direct sunlight of 25+C (77F).
Plant into pots, baskets or soil in the ground when you see the first flower form. When planting outside, keep them 45-60cm apart. Spreading black plastic over the soil surface and planting in slits made into the plastic will give tomatoes plants a head start. The roots will appreciate the increased soil warmth that the plastic allows.
How to take care of Tomato plants
Feeding Tomato Plants
Add a general-purpose fertiliser to soil before planting, and if digging over the soil in winter, add bulky compost to increase the soil fertility.
For container-grown tomatoes, feed regularly with tomato feed. Feed little and often – this will ensure the tomato fruit ripens well and does not split, which is an indicator of sporadic yet deluge-like feeding.
How to water Tomato Plants
The watering of tomato plant’s needs (like feeding) to be a little and often, rather than sporadically. Tomatoes are thirsty plants and for healthy growth need water regularly and evenly.
- You should water the plant generously the first few days. Then water well throughout the growing season.
- The best time to water the plants is early in the early morning. This provides the plant with the necessary moisture it needs to make it through a hot day.
- Avoid trying to water the plants in the late afternoon or evening.
- Be aware that a rain-shower will not be enough to substitute a proper watering of the plants.
For plants grown indoors, misting the plants will keep humidity up, and allow a more favourable growing environment for the plants. You can water the floor of the greenhouse to encourage rising humidity.
The Don’ts of watering
If young seedlings or young plants have rotted, more often than not it’s down to over-watering. To help prevent this from happening;
- When young, water from above when soil feels dry until roots are emerging from the bottom of the pot.
- Never stand pots in water for a length of time. Roots need to breathe and get sufficient oxygen; if you keep them standing in water they drown.
A good tip for established plants is to stand them in a tray of water overnight, if the soil is dry. In the morning tip out the excess water from the tray. Only ‘flood’ the tray again when soil surface feels dry to the fingertip. Again, make sure you re-visit after a few hours or overnight to tip out excess water.
How to prune tomato plants
Indoor cordon-types -
- Tie the main stem loosely with string or twine to a central cane.
- As the young plants grow, side shoots will grow out of where the leaf stalks join the stem. Pinch these out once they reach 3cm (1in).
- Once the plants are 1.2m (4ft) tall, remove leaves below the first flower stem. This is called the ‘truss’ and the flowers stems turn into the tomato vines.
- Remove yellowing leaves as the season goes on but look to remove only about a half of the yellowing leaves.
- When the plants reach the top of the roof or you’ve counted around seven trusses. Pinch out the tip at 2 leaves above the top truss.
Outdoor bush-types -
These tomatoes do not need as much pruning , and you can enjoy the fruits without any truss- counting, stem pinching etc. Although they are easier to grow in this respect, they are needier in other respects and you may need to be vigilant in spotting more pest and disease damage or nutrient deficiencies.
Harvesting and Storing Tomatoes
Harvest fruits when they are ripe and deep red, but still possess firmness to grip. Twist them off so they break off at the swelling of the old flower stalk.
For any remaining green tomatoes at the end of the season, harvest and place them either on straw under cloches, in a warm dark place or in with other ripe fruit to encourage ripening quickly. Alternatively pick and use the green tomatoes for chutney, curry and other recipes that take advantage of the tang of unripe tomatoes. Tomatoes stay fresh for a week when refrigerated. You can pulp tomatoes and freeze as a passata for future use.
Common pest and disease problems
- Blossom end rot - A dark patch at the base of the fruit will appear. This is more more common if the plant is grown in a grow bag.
- Split fruit – Does not affect the taste, however, will most likely cause infection by fungus
- Dry set - Fruitlet growth stops when the fruit is the size of a match head.
- Tomato blight – A disease that causes fruit and foliage rot, this is most common in wet weather.
- Leaf yellowing – This is caused by a disease and can lead to significant yield loss. Leaves will start to yellow, and mould is found on the lower surface.
- Mosaic virus - Mosaic patterns of lighter green on the leaves.
Health benefits of Tomatoes
Tomatoes are incredibly good for you. They contain vitamin C which boosts the immune system and they’re full of powerful antioxidants and carotenoids. One in particular, lycopene, may help prevent certain types of cancer.
You may also need
For great results, grow your tomato plants in grow bags with our specially designed Tomato Grow Pots, which make watering easier and offers support at the base of your plants. The Big Drippa Watering Kit is a gravity-fed watering system, not electronics required and keeps your plants watered for up to a week!