Help us achieve our goals:
make a donation »
Join the RHS today and
support our charity
Free personalised gardening advice
RHS members get reduced ticket prices
RHS members get free access to RHS Gardens
Reduced prices on RHS Garden courses and workshops
020 3176 5800
Mon – Fri | 9am – 5pm
Make a donation
Join the RHS today and support our charity
I have forgotten my password
Keep me signed in
Register for free to receive our newsletters, add comments to blogs/articles and to save content.
Plant up containers with Hippeastrum (amaryllis) bulbs and plant prepared Hyacinths by 24 September to get flowers for Christmas.
Start to reduce watering of houseplants as light levels drop.
Damping down usually becomes unnecessary as the month progresses. It is best to do any watering or damping down earlier in the day, so that the greenhouse is dry by evening. Dampness during the cool nights could be a recipe for a fluffy grey mould (Botrytis) and damping off of seedlings.
Ventilate conservatories during warmer days but reduce ventilation once the cooler weather sets in. Use shading paint or blinds to help keep the area cool, but be ready to reduce shading towards the end of the month as light levels fall.
September is an ideal time of the year to apply biological controls for use on vine weevil. Grubs will be starting to hatch, and soil and compost temperatures are now suitable for the nematodes to be effective. Target vulnerable plants, such as fuchsias, succulents and containerised plants.
When bringing plants indoors, check carefully for any pests and diseases they may have picked up outside, in particular red spider mite, mealybug and scale insect. Inspect rootballs and compost for vine weevil larvae and treat where necessary.
the RHS today and get 12 months for the price of 9
greenhouse, conservatory & houseplants
Things to do in the garden this month
Trees and shrubs
Greenhouse, conservatory and houseplants
We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.
Join the RHS today and get 12 months for the price of 9