Early autumn is a fun time in the garden, when warm days combine with cool, dewy nights to create ideal growing conditions. After the heat and drought of an average August, plants and gardeners alike are refreshed and spurred on to a flurry of planting and harvesting. Flower gardens offer a mixture of maturity and freshness as fulsome  dahlias and fuchsias combine with the globe-like seed heads of allium and silky beards of Clematis tangutica. There are glowing fruits on crab apples, pyracantha and rowan and by contrast, fresh colours as Nerine bowdenii and hardy cyclamen come into bloom. In the vegetable garden, beans, marrows and tomatoes will be at their peak, with pumpkins slowly turning colour. Keep up with sowing, thinning and planting hardy salads, turnip and chard for crops through autumn and winter.

in the vegetable garden...

- plant out hardy lettuce varieties such as ‘Valdor’ and ‘Winter Density’ sown last month or bought in modules. Set them in long rows either side of a garden line, so they will fit under a tunnel cloche during cold weather. Guard against slugs.

- plant out autumn onions sets in clusters of three, with 8cm/3in between the plants and 30cm/12in between the clusters. Leave the tips just showing, but check to make sure birds aren’t pulling them out.

- ripen the last tomatoes by hanging the vines in a dry shed. Place individual tomatoes in the greenhouse to turn red in the sun, or put them in a paper bag with a ripe banana. Ethylene gas given off by the banana helps the tomatoes redden.

in the flower beds...

- start lifting, dividing and replanting clumps of overgrown herbaceous perennials that will die back during winter, starting with those like some hardy geraniums, lungworts (pulmonaria) and Brunnera that need time to settle before flowering in spring.

- pull up bedding plants as they go past their best. Fork in soil conditioner and gradually replace with groups of biennials like sweet williams, forget-me-nots, foxgloves and for hot, sunny places clary sage (Salvia sclarea) and verbascum.

- plant new clematis while the soil is moist and still warm, as their roots will establish quickly ready for a good start next spring. Water first, plant into good soil and set the top of the rootball 10cm/4in deep as protection against damage or wilt.

and in general...

- tidy regularly by dead-heading and cutting away mouldering foliage to keep borders bright and beautiful. Leave attractive seed heads standing, but remove decaying leaves and flowers or stems that are leaning about and spoiling the late sow.

- pot prepared hyacinth bulbs by mid month if you want them to flower by Christmas. Set them in bulb fibre, water and place in a cool, dark place. Check for watering and move them into the light when buds are 2.5-5cm/1-2in tall.

- leave your cymbidium orchids outdoors or in an unheated greenhouse to feel the cooler nights. This helps initiate flower buds. When buds appear or well before the first frosts, bring them in under cover.

QUESTION TIME

Q Why are my carrots coming up with hard green tops?

A When carrots are grown close together, they tend to force each other up out of the soil. When the top is exposed, the cells there produce more green chorophyll than carotene (the orange pigment) so they can help make plant food. The green tops are safe to eat (unlike green potatoes) but if you don’t like them, thin carrots to wider spacings or mulch to cover the tops.

Q What are your favourite rose varieties for scent?

A Red-flowered climbers ‘Etoile d’Hollande’ and ‘Guinee’, though the latter is a bit spindly and looks best mingled in with other climbers. The pink-flowered English shrub rose Gertrude Jekyll has delicious fragrance, as does peach Crown Princess Margareta and pale yellow The Pilgrim. White floribunda ‘Margaret Merrill’ is legendary and for a large shrub, purple-red ‘Roseraie de l’Hay’ is virtually disease proof.