Flower borders may be starting to fade, but late summer is a time of “mellow fruitfulness” in the garden. Most summer crops can be gathered in, with tomatoes, peppers, sweet corn, and squash reaching their peak. Use the warm days for cleaning and organizing tasks too.
The first apples and pears in the garden should be ready to pick from August onward. When you see one or more apples on the ground, this is a sure sign that the fruit is ready to harvest. If you cup an apple in your hand and gently twist it, a ripe fruit should detach effortlessly from the tree, stalk intact. If it does not come away easily, leave it on the tree for a few more days before testing again. Pears should be harvested while slightly underripe and ripened indoors.
Continue to feed tomato plants with a high-potash feed applied weekly. Water plants every evening if possible. If you have green tomatoes toward the end of the season, bring them indoors to ripen on a sunny windowsill or in the fruit bowl. Remove any yellowing leaves, and thin any foliage clustered around the trusses of fruit. As well as allowing more light to reach the fruits and ripen them, this will improve air circulation around the plants and reduce the possibility of botrytis, also known as gray mold.
Female winter moths are unable to fly, so will climb apple and pear tree trunks to lay their eggs during winter. To catch them, fix sticky tree band traps around the trunks. Use the bands on stakes too, to prevent moths from reaching the trees via tree ties.
When the foliage collapses, onions are ready to harvest. On a dry day, gently ease the onions out of the soil, and leave them out to dry. To ensure that they store well and do not rot, they must be completely dry—if the weather turns wet, cover them with a sheet of plastic, or move them indoors.
Leaves will start to fall as autumn approaches, so ensure that you cover your pond with special netting to prevent dead leaves from falling in and affecting the water quality. Nets will also protect your fish from herons and other predators.
Fallen leaves will collect on your lawn in the fall and can kill off the grass if left in a thick layer, as well as encouraging slugs and snails if left lying over and around plants. Rake leaves up regularly, and use them to make leaf mold.
Once your lavender plants have flowered and started to fade, go over the plants with a pair of shears, cutting them back. This will encourage side shoots to grow and give plants a bushier, more compact look. Rambling roses should also be pruned after flowering.