Autumn Greenhouse Calendar - October

• There’s much less work to do in the greenhouse in October, now that summer heat is gone and summer crops are waning. No more daily waterings, no more floor and wall damp-downs, and no more Tomatoes and Cucumbers to nurture. Chrysanthemums, Pansies and Carnations provide most of the color now.

It’s time to start thinking about heating and insulation. Early October is the ideal time for your annual greenhouse clean-up. The goal should be to complete the clean-up before you bring in the first frost-sensitive plants.

GENERAL PLANT TASKS

• Cut back frost-sensitive plants and bring them into the greenhouse to overwinter.
• Take fall cuttings from healthy plants.
• Cut back and store the parent plants from which summer and fall cuttings were taken.
• Bring in tuberous begonias by first frost.
• Stop watering Cacti when temperatures drop below 40. (Without a suitable winter dormancy, Cacti are unlikely to flower.) Exceptions to the no-watering rule: Epiphytic cacti which flower in winter, including the "Christmas Cacti" hybrids, which will need watering until after they flower. Don’t move Christmas Cacti once they’ve budded. Some South American cacti can be watered lightly on sunny winter days.
• In warmer climates, the Tomato and Cucumber season comes to an end.
• At the end of October, transplant cuttings taken in September.

Bulbs

• Plant more containers of forcing bulbs to get January and February blooms.
• lant traditional spring-flowering bulbs such as Tulip, Hyacinth, Narcissus and Crocus for display in the greenhouse or living room.
• Pluck out Cyclamen seedlings.
• Dry off Begonia, Gloxinia, Likly, Achimenes, Canna, etc., once flowering has finished.
• Water and feed Freesia, Cyclamen, Lachenalia.

Other Ornamentals

• Prick out last month’s sowing of annuals. Pinch out the growing tips of older seedlings to encourage bushiness.
• Reduce watering of established plants; avoid waterlogging at all costs.
• Cut Chrysanthemums and Carnations for indoor arrangements. Be on the lookout for grey mould and earwigs on Chysanthemums.

Bedding Plants

• Overwinter Fuchsia and Pelargonium; keep relatively dry until time to bed out in May or June.
• Pot rooted cuttings.
• Sew Sweet Peas for planting out in spring.

Garden Perennials and Shrubs

• Take cuttings of evergreens; use rooting hormone.
• Pot up Lily bulbs in 8" pots for planting out next spring.
• Lift Dahlias when first frosts have blackened the foliage. Cut down to 6" and label. Box up tubers and store under your greenhouse staging until spring when the young shoots can be used as cuttings.

Vegetables & Fruit

• Pick all tomatoes before the middle of the month. Ripen in a drawer or paper bag. Wrap individually in newspaper to prevent rotting.
• Plant up seedlings sewn last month.
• Sow a spring-cropping of Lettuce such as May Queen.
• Harvest Capsicum, Aubergine, Radish, Mustard, Cress and Mushroom.
• Reduce fruit watering. Ventilate established Peach and Nectarine, which require cool and dry air in order for wood to ripen.
• Harvest Grapes.

Greenhouse Tasks

• Maintain a minimum night temperature of 42 - 45 degrees. Monitor the weather forecasts closely. If frost is forecast, drape tender specimens with matting, straw or newspaper.
• Control the venting manually on warm days. Make sure there’s always plenty of fresh, moving air in order to prevent condensation. Ventilate each day between mid-morning and early afternoon, using the roof ventilators only. Don’t ventilate on damp or foggy days. Close vents at night.
• Cease damping down. The additional humidity which was so necessary in the summertime is no longer required. Moist air can encourage mold.
• Water judiciously before midday, to allow time for splashes to dry before sunset. Make sure a plant requires watering before you water it. Don’t splash water around the greenhouse. Keep water off the floor, staging and leaves and crowns of the plants.
• Remove and store shading material.
• Do annual greenhouse cleaning.
• Inspect your plants. Remove dead flowers and yellowing or diseased leaves. Put down slug pellets if you notice slime trails or damaged foliage. Spray if grey mould or whitefly is observed; spray only in the morning.
• Bring all half-hardy plants inside the greenhouse.
• Begin installing installation when nighttime temperatures drop into the low forties. If daytime temperatures climb, make sure your greenhouse is adequately vented to prevent excessive humidity and condensation.
• By the end of October, you may need to use heaters on the cooler nights.