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18 Apr 2020

This is why your tomato plant looks ill, plus other veg problems

Get timely advice to make your veg garden a success

Whether it's your first time growing veg or you've done it for several years, there are several common problems that can trip us up in spring.

The Which? Gardening experts will help get your veg garden back on track by showing you how to fix problems, from sickly tomatoes to brown potato leaves.

Sickly looking tomatoes

Tomatoes don't like cold temperatures and will turn brown and sickly looking if they get chilled. Even though you may see plants for sale outside shops, it's still too early to plant them outdoors. Ideally, plant them in growing bags, large pots or the border in a greenhouse. If you don't have one, keep them indoors in a brightly lit spot until you can safely plant outdoors when the danger of frost has passed in mid-May. Plants that have been damaged by cold should recover when they're brought indoors.

Watch our video about how to grow tomatoes

Success with parsnip seed

Parsnip has a reputation for producing patchy results. It's definitely worth getting fresh seed every year, as seed quality deteriorates over time. Wet the seed drill before you sow and keep the soil moist for at least two weeks after sowing to help encourage germination. Remember that windy weather can be just as drying as sunny spells.

How to avoid getting forked parsnips

Sowing beans

While it's a good time to sow other tender veg, such as courgettes, it's still too early to sow both runner beans and French beans. This is because they don't really thrive until the weather is warmer, so it's best to hold fire until May. May sowings will grow quickly and it won't be long before they're ready for planting outside.

How to grow runner beans

Growing basil

Basil loves warm conditions to germinate and dislikes wet feet, so add perlite to the compost to improve drainage. Try to avoid disturbing the roots by pricking out. Sow into modules instead. When plants are about 15cm tall, pinch out the main growing tip to encourage them to bush out.

Don't plant out until the danger of frost has passed in your area (usually mid-May) and put them somewhere in full sun. They also do well in the greenhouse. Pinch out any flower buds that appear. This will channel the plant's energies into producing leaves.

Brown potato leaves

Potatoes can be grown in the ground or in large pots. They're usually planted from mid-March to the end of April, so you've still got time to plant if you haven't done so yet. If your plants come up and seem to be growing well before their leaves turn brown overnight, they've been damaged by frost. They should grow through the damage and recover. To avoid it happening again, cover all the leaves with earth or compost as they emerge. This will protect them from cold and also discourage the potatoes being too near the surface where they could turn green and be poisonous.

Watch our video guide to growing potatoes

Visit the Which? Gardening helpdesk for more advice about gardening problems. Members of the magazine can email our experts for gardening advice any time.