Houseplants
Move conservatory plants, such as Cymbidium, Ficus and Citrus outdoors during warm days but bring back inside if cold nights are expected.
Clean shiny-leaved plants (such as Anthurium, pictured) with a damp cloth, and spiky plants with a soft brush.
Pot up houseplants showing signs of being rootbound or top-dress large containers with fresh peat-free compost.
Cool conditions and regular watering will help keep potted indoor azaleas looking good for longer. Remember to water azaleas with rainwater collected in a water butt, not with tap water.
In the greenhouse
Apply shade paint to the outside of the glass or use blinds on sunny days to prevent temperatures from soaring.
Open doors and vents on greenhouses to increase ventilation on warm, sunny days.
Damp down the floor of the greenhouse on hot days, to increase humidity levels. This benefits plant growth and also reduces the risk of pest problems such as glasshouse red spider mite. Use rainwater or grey water (such as washing up water) where possible.
Don’t forget to give greenhouse plants more space as they grow. This will help to prevent disease and reduce spread of pests.
Harden off your half-hardy bedding plants that were started off early under cover. By placing them outside for a short period only, at the warmest time of day, and then gradually increasing the length of time they are outside, you can avoid the ‘cold shock’ that they otherwise experience when moved outside suddenly and permanently.
Check plants at least every few days, to see if they need watering. Seedlings will need daily attention. Use rain, grey or recycled water wherever possible.
Continue to prick out and pot on new seedlings and cuttings.
Try growing on plug plants in your greenhouse. They are a relatively cheap and time-saving source of large numbers of plants, and don’t need propagation facilities.
Hydrangeas and fuchsias can be propagated from softwood cuttings.
Pot on any Begonia, Gloxinia and Achimenes plants that you started off earlier in smaller pots, but are now ready to pot on.
Pruning and training
Train the new stems of passionflowers (pictured) and other glasshouse climbers over frames or on horizontal wires.
Support the stems of indoor crops such as tomatoes, peppers and aubergines with a cane as they grow. Stems are much less likely to break or grow in the wrong direction if they’re trained from early on.
Problems
Regularly inspect plants, and also the structures of the greenhouse and conservatory, for glasshouse red spider mite, whitefly, thrips and other pests. Check the undersides of the leaves of each plant to spot problems early. Remove by hand or use biological controls, and hang yellow sticky traps to help monitor numbers of flying pests.
Damping down the floor of the glasshouse on hot days, preferably with rainwater or grey water, will reduce the risk of glasshouse red spider mite.
Brush up fallen compost and debris, and pick off dead leaves from plants. This will help prevent spread of pests and diseases.
