What to do in your garden in September?

The gardening year is turning to its last dazzling farewell display of autumn colour soon, so it’s time to shake yourself out of the torpor of late summer and get going again. There’s loads to do outside from gathering crops to putting the garden to bed for winter. Here’s your list of jobs for this month: 

 

General tasks

• Scarify, aerate and topdress established lawns while the soil is still warm so the grass can bounce back in double-quick time.
• Net ponds in plenty of time, before the leaves start to fall and clog up the water. Remove any dead or dying foliage at the same time to keep the water clear.

Ornamental gardens

• Divide summer-flowering herbaceous perennials to keep them young and fresh: cut back top growth, lift the clump then split with a fork before replanting or potting up the divisions to make new plants.
• Lift tender perennials like Mexican salvias and pelargoniums before the first frosts. Cut back the top growth by a third, pot up into fresh compost and place in a frost-free greenhouse for winter.
• Replace spent summer bedding with winter pansies, heathers and cyclamen for flowers through the coldest months of the year – you’ll find a great selection on sale now at the garden centre.

Kitchen garden

• Plant autumn onion sets 2cm deep and 10cm apart for an early crop of delicious fat bulbs next June, a full month before maincrop varieties are ready.
• Pick autumn-fruiting raspberries as they ripen and freeze in a single layer laid out on trays overnight before decanting them into plastic bags for the freezer.
• Ripen green tomatoes by taking plants off their supports and laying them flat on a bed of straw before covering them with a cloche to intensify the sunlight.