Follow the checklist below when tending to the greenhouse in autumn.
- Reduce watering and feeding as growth slows. Stop damping down, only water in the mornings and avoid wetting foliage to prevent fungal diseases, which thrive in a damp atmosphere.
- Open ventilators on mild days, but keep them closed during frost or fog.
- Allow permanent plants more space, to improve air movement between them.
- Remove shade netting and paint and wash down the outside of the glass. Shield young seedlings from bright sunshine with sheets of newspaper or a layer of fleece.
- Pot up seedlings of annuals and other plants sown in late summer.
- Pot up well-rooted cuttings of tender perennials and other plants propagated in late summer.
- Sow hardy annuals, prick out into trays and overwinter in a coldframe.
- Sow sweet peas in deep pots of seed compost or paper tubes.
- Lift and dry bulbs and tubers ready for their winter rest.
- Pot up lilies in deep pots for flowering in their containers or for transplanting outdoors in spring.
- Make space for tender perennials that have stood outdoors during summer before the first frosts come. First scrub the outsides of the pots and check the plants for any evidence of insect infestation.
- Stop watering cacti to keep them dry and safe from frost.
- Pot up some hardy perennials such as Astilbe, Aquilegia, Dicentra and hellebores, to flower early indoors.
- Check for pests, especially whitefly and red spider mite, and spray with insecticide. It is too late to introduce biological controls, which are only effective in warm conditions.
- Pick off fading leaves, dead flowers and any sign of decay or mold, to reduce the risks from fungal diseases.
- Clean and sort pots. Clean out gutters and water barrels or tanks when leaves have finished falling.
- Pot up spring bulbs for indoor displays.
- Bring potted spring bulbs into light and warmth when shoots reach 2 inches (5 cm) high.
- Move potted herbs inside to keep the kitchen supplied during winter.
- In late autumn insulate the greenhouse and test heaters before they are needed. If you plan to install heating, decide on the types of plants you are likely to grow and the temperature regime they prefer.
- Make repairs to the greenhouse and coldframes before winter.
- Clean the greenhouse before it fills up with tender plants.
The Reader’s Digest Association Inc./GID
Slightly open the greenhouse ventilator to allow for air circulation.
