This year on 21st September, the weather changed to autumn at the flick of a switch. Night temperatures dropped dramatically, friends nearby had their first frosts and mornings started with that wonderful organic smell of autumn but warmed as the day progressed.
The tomato plants were lifted and stripped of fruit, some partially ripened are in bowls on the window sill, other blemish free fruit was stored in a cool drawer, to be ripened in the fruit-bowl or in a paper bag with an over ripe banana, as needed during the winter. They are checked regularly, as you would your apples, removing any showing signs of decay, making sure there is a good gap between the fruit and that they are not touching each other. Outdoor tomatoes were brought into the greenhouse to finish ripening. It was also an opportunity to weed through the greenhouse removing any debris that is pest and disease free and adding it to the compost heap.
Tender plants in pots, including cacti and succulents will be stored in the greenhouse, some under benches, before the first frosts, cutting back foliage on plants like pelargoniums to save space. Ventilate the greenhouse on sunny days, shutting the windows by the middle of the afternoon to capture the warm air, so it cools down slowly as the day draws on.
Dahlia tubers and Cannas can be overwintered outdoors in warmer areas, though it is a gamble, in case the winter turns cold and should definitely be lifted in cooler areas and stored in a cool frost-free greenhouse. Once the first frosts have blackened the foliage, cut back the stems to within 5cm of the base. Make sure the labels stay with the dahlia tubers, turn them upside down on the greenhouse bench for a few weeks, so water drains from the hollow stems, then turn them upright and store them in trays, covering the tubers covered in a thick layer of compost for protection – spent compost from hanging baskets and containers is ideal. Canna’s just need to remain with their labels and be protected with a layer of compost.
Sow sweet peas indoors from October into November. Soften the seed coat by putting the seeds on a layer of kitchen towel on a dinner plate, put another layer on top. Dampen the towel, drain off excess water and sow as soon as they begin to swell or sprout, usually after about 48 hours. Compost those that don’t swell and germinate. Sow the living seeds individually into ‘Root Trainers’ or 9cm (3in) pots of seed compost or five to seven seeds to a 13cm (5in) pot, with the seeds spaced 2-3cm (¾-1¼in) apart, then cover the seeds with 1cm (½in) of compost. Water in gently, cover the pots with clear polythene then put them in a propagator or warm room at about 15°C (59°F). Remove the covering after they have germinated and overwinter the young plants in a cold frame or unheated greenhouse. If not sown individually, transplant single seedlings into 9cm (3in) pots once they have reached about 3.5 cm (1½in)
Check over your stored greenhouse plants daily, removing yellowing or dead leaves and faded flowers before rots develop. Remove and compost any dead foliage affected by red spider mite or summer greenhouse pests in your council green bin. Happy gardening. Matt