Growing tips for the tastiest tomatoes
Hardening off
'Harden off' your plants by gradually introducing them outside in early May. Bring them inside on nights below 10°C to prevent a check in growth. We've experimented by leaving plants out at 5-7°C in April, they survive but quickly look weatherbeaten and don't do as well as plants that have enjoyed uninterrupted growth above 10°C - problems include low pollination rates and scarred fruit. Avoid planting next to other plants from the Solanum family, like potatoes and aubergines, to reduce the risk of tomato blight (a fungus caused by wet, humid conditions) which can spoil your harvest. Some say planting next to vigorous plants such as sweetcorn or cabbage should also be avoided.
Planting out
It's easiest to remove your plants from their tomato cans when the compost is dry. Place your fingers palm down either side of the stem to avoid damaging the stem, turn the plant upside down and shake out. Slip a butter knife down the sides of the can if you're having trouble. Be careful of sharp edges around the drainage holes.
Choose your sunniest, most sheltered spot. Fork in some organic matter (a rich compost is fine) into the soil first. If your soil is very dry, use a soil improver like farmyard or horse manure worked in a fortnight before. As a rule of thumb, 30% compost or soil improver relative to your soil volume is enough. Avoid planting into excessively wet, waterlogged soil, or anywhere standing water gathers after heavy rain. If you're happy with your soil condition, just mix in a few handfuls of decent compost at the bottom of the hole you've dug. Gently loosen the roots with your fingers to encourage your plants to grow into their new environment. Drop your plant into the ground so that the soil surface is level with the two initial (smallest) leaves - the hairy stems at the base will put out new roots providing for a larger root system and stronger plants. Gently 'heel in' the soil surface around the plants so they are stable.
Remove any leaves that trail and touch the ground to reduce the risk of blight. Allowing air to circulate beneath your plants will significantly reduce blight risk!
Repotting
If growing in pots, RHS recommend at least a 30cm (12inch) diameter size. Place 'crocks' (curved pieces of broken crockery) over a few of the drainage holes to ensure good drainage before filling with best quality compost.
Support
We've started your plants very early in the season so expect a lot of upward growth in May. If using bamboo canes to support, use the tallest you can get your hands on and drive them as deep into the earth as you can to ensure stablility. Ideally secure the tops of canes to wires fixed in walls or fence posts etc. Strong winds will bring heavily fruiting plants down in unsheltered areas. Tie the main stem of the plant to the cane at intervals as they grow (not too tightly as the stem will thicken) using jute twine (you can get it at Poundland or B&Q), we prefer to use cut-up old t-shirts as they don't bruise the stem, breathe well and dry quickly after rain preventing trapped moisture which can cause disease.
Slug and snail prevention
If you're uncomfortable with harming slugs and snails, apply copper tape to pots, or you could collect them at night with a torch and a jar and take them to Epping Forest.
OK: egg shells broken up and coffee grounds around the base of plants.
GOOD: copper tape making a full circuit around your pots.
VERY GOOD: Beer traps (can be non-alcoholic beer, the slugs are after the yeast). We push yoghurt pots or dessert ramekins into the soil and fill with cheap beer. There are worse ways to go...
EXCELLENT: beneficial nematodes. Unfortunately they're expensive. They take effect a fortnight after application and will last around six weeks. We apply on a rainy evening before the planting out stage for peace of mind. As the nematodes take effect, you'll notice slugs loitering about in open daylight looking... sluggish.
Side shoots
The conventional advice is to pinch out until you have around five or six fruit trusses in total to ensure the plants have enough energy for their fruit to set and to ripen. Some types (for example San Marzano 2) may benefit from being limited to 3 or 4 trusses to ensure the heaviest crops and best flavour. But if you don't want very long/tall vines, you can pinch out the topmost growing tip of the plant and let some side shoots grow to increase the number of fruit trusses. Here's an easy to follow 1 minute video from Charles Dowding on how to pinch out side shoots.
Pollination
Tomatoes are largely self-pollinating but benefit from additional help from the wind and pollinating insects. You can help disperse pollen by gently shaking the plants by hand. Especially enthusiastic growers can stimulate their flower heads with an electric toothbrush! That said, despite pollinator numbers declining (see Wildlife Trust's recent appeal to gardeners to help as hoverflies join the Red List of threatened species) we've never needed to manually aid pollination in Leyton.
Feeding
The advice on bottles of tomato feed concentrate is to start feeding your plants when the first fruit truss has 'set' (fruit are visible all along the truss) on a 7-10 day cycle. But avoid overdoing a liquid feed. James Wong says tomato trials show that overfeeding can result in less flavoursome fruit. You can also cut pieces of banana peel and steep them in a large jar of water for a few days to give your plants a boost of potassium.
Watering
Use rainwater if you have a butt but tap water is alright! If you've plated into soil beds it's better to water deeply but infrequently to encourage roots to grow lower. Water in the morning rather than the evening to reduce the risk of blight. Avoid watering the foliage if possible.
Harvesting
Tomatoes need direct sunlight to get really sweet - prune sparingly if you have excessive foliage. We find fruit tastes best if picked before watering and when they're really, really ripe. If you have a glut, roast them and force through a sieve to remove skins and seeds and freeze the sauce for next year. Or make a classy Bloody Mary, or ketchup - Jamie Oliver's recipe is great.
If you have a windfall of unripe fruit, collect them in a bowl for your kitchen with ripe bananas resting on top. The additional ethylene gas produced will trigger the ripening process.