TOMATOES
Sow: January to April
Plant: April to June
Harvest: June to December
January: Buy seed. Earliest sowings can be made with heat, but it is safest to wait.
February: Sow seed thinly and cover with a sprinkling of compost, water lightly and put the tray in a clear polythene bag. Keep between 15˚C/59˚F and 25˚C/77˚F. Don’t exclude light. Germination takes 6–10 days. Remove the bag once seedlings appear.
March: Sow seeds as for Feb. Pot seedlings on into 8cm/3in pots. Maintain a temperature of around 18˚C/64˚F.
April: You can still sow seed, but you’ll get faster crops if you buy in plants. Harden off before planting out at the end of the month (if above 10˚C/50˚F). Provide a potash-rich growing medium and canes or strings as support. Allow 45cm/18in between plants and 90cm/36in between rows.
May: Tie the stems in to the supports as the plants grow. Nip out side shoots in the joints between leaf and stem. Open doors on hot days. Water regularly and lightly mist first flowers.
June: Spray first trusses of flowers with a light mist of water to help fruit set. Keep nipping out side shoots and tie in stems every 15cm/6in. First green fruit should start to swell and ripen. Water regularly. Keep tunnel doors open if hot.
July: Watch out for disease. Remove any discoloured foliage. Keep the soil watered. Start feeding every week with a liquid feed. Pick tomatoes as they ripen. Start removing lower leaves.
August: Harvest regularly. Keep nipping out side shoots and check the base of the plant for unwanted new shoots. Feed plants every week and mist overhead if the polytunnel reaches high temperatures. Remove lower leaves to expose fruit to the sun.
September: Remove any blighted leaves and fruit before the problem spreads. Nip out the growing point if plants ramble too much, or leave it to grow for a crop of late fruit. Pick up any fallen fruit that may scatter seed on the ground.
October: Remove failing plants. Leave healthy plants to provide fruit for a few weeks yet. Remove leaves, so that stems are almost stripped and only the healthy top growth is left to feed the plant.
November: If leaves blacken, pick all fruit and clear plants out of the tunnel. Clear the ground of all dropped leaves and fruit – this avoids carrying disease into the next year’s crop.
December: In a mild winter plants may slowly ripen fruit, but always clear them out of the tunnel before the end of the year.
TOMATO TROUBLES
Caterpillars: July to September
Red spider mite: May to September
Whitefly: April to October
Aphids: March to December
Leaf mould: June to December
Blight: June to November
Grey mould: June to December
Blossom end rot: June to November
Greenback: June to November
Dry set: March to July