Summer in the greenhouse - A guide

Now that the bedding plants have all been taken out of the greenhouse, it is time to space out the other plants to give them room to grow. Look over them as you do so, to check for pests and diseases. Also take the time to repot any that need it. Most plants will need feeding now, especially established plants that have been in their pots for a year or more. Citrus, such as oranges and lemons, can be put outside along with other plants but only if the weather is mild. The shock of changing conditions can damage the foliage of many plants, including citrus, and they will benefit from a little shade because the sun, combined with wind, will scorch leaves.


Ventilation
Increase ventilation to its maximum now because it can get very hot in the greenhouse on sunny days. High temperatures damage plants as well as causing water loss. Fit automatic vent openers if you do not have them and leave the greenhouse door open on warm, sunny days.

Watering
Most plants will need plenty of water now but never be tempted to water with a hose, sprayed over the bench. Any plants that have been recently potted will not have the same water needs as established
plants and it is easy to overwater them, causing root damage and even death.


Damping down
Maintain a humid atmosphere, if possible, by spraying water on the floor of the greenhouse as frequently as possible on hot days. Ideally, do this in the morning or at midday.


Pests
Warm weather means pests will be breeding fast. This is an ideal time to order and introduce biological controls for whitefly, mealy bugs and red spider mite.

Beware moths
Look out for tortrix moth caterpillars. These small, brown moths lay eggs on a range of plants. The caterpillars pull leaves together for protection and eat the foliage or, in this case, my lemons!
Pick them off affected plants and squash them.