Jo Whittingham: Autumn harvest should still be going strong

This month the garden definitely starts to wind down as the nights grow cooler and the days grow shorter. After our rather mixed bag of a summer, my greenhouse tomatoes only started ripening in quantity two or three weeks ago, leaving a substantial crop of fruits still to take on a hint of orange, let alone turn red.

You may have to remove some leaves to help tomatoes ripen. Picture: Getty Images/iStockphoto

This isn’t too much of a worry, because with a mild autumn it’s possible to still be picking tomatoes and peppers from the greenhouse well into October, but a few simple tricks can help speed the ripening process along. High light intensity is important for ripening, so remove any greenhouse shading now and cut down any other tall plants which have finished cropping, such as cucumbers. Snapping or cutting off the large lower leaves of the tomato plants not only allows the sun to reach the fruit, but also increases air-flow around the plants, which helps prevent fungal diseases striking. Be sure to remove any withered or mouldy leaves quickly, and keep feeding and watering the plants consistently, but increasingly sparingly, to help prevent fruits splitting and maximise flavour. If fruit fails to colour, be sure to try some cherry tomatoes next year because their smaller fruits ripen the fastest.

Elsewhere in the kitchen garden, autumn raspberries and many apples are ready for picking this month, and the last potatoes, carrots and beetroot will need lifting. Any late sowings of dwarf beans, lettuce and other crops that will suffer as temperatures drop can be covered with cloches or fleece to see them through to harvest. The beginning of September is a great time to plant out spring cabbage, so it establishes and overwinters well for picking as spring greens from February and hearted cabbages from April into summer.

Keep flower borders looking fresh by cutting back herbaceous perennials as they fade, just leaving choice flowers and seedheads for autumn and winter interest. Climbing roses should also be pruned and tied into supports this month, while any unkempt evergreen hedges will benefit from a final trim. This is also an ideal time to create a new lawn, either by laying turf or sowing seed. An enormous variety of spring bulbs, such as daffodils, crocuses and Muscari (grape hyacinths), can be planted from now right through autumn, although tulips are best left until November to reduce the risk of disease. Fill every gap in the border, and all the containers you own for an explosion of colour to welcome in spring. The garden may be winding down, but it will be a couple of months yet before gardeners can do the same. n