What to do during July in your garden and greenhouse.

Your monthly gardening checklists

Flowers

Geranium x magnificum

Cut back geraniums and other summer perennials.

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Fruit and veg

Protect brassicas from cabbage white butterflies with fine netting

Greenhouse

  • Open greenhouse vents and doors on warm days to improve air circulation
  • Continue pinching out any side shoots growing from the leaf joints of cordon tomatoes
  • Take cuttings from fuchsias, coleus, pelargoniums, marguerites and other tender perennials
  • Water tomatoes daily to prevent drying out, which can lead to split fruits and blossom end rot
  • Order cold-stored potato tubers for planting in a greenhouse or cool porch next month, to harvest at Christmas
  • Damp down the greenhouse floor each morning on hot days to increase humidity
  • Be vigilant for aphids, vine weevils and other pests, and treat immediately so infestations don't get out of hand
  • Feed tomatoes, chillies and cucumbers with high-potash tomato fertiliser every week to encourage fruiting
  • Install a reservoir watering system, so thirsty plants such as tomatoes don't dry out
  • Regularly sweep greenhouse staging and floors to reduce debris that can harbour pests and diseases
  • Train the main stem of cucumbers up supports and pinch out sideshoots two leaves after a flower or fruit

Damp down greenhouses on hot days to increase humidity

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Garden maintenance

  • Compost your kitchen and garden waste, chopping up and mixing the contents to speed up decomposition
  • Top up bird baths, ponds and water features during hot weather
  • Water new trees, shrubs and perennials planted in spring, to help them through dry spells
  • Trim conifers and other garden hedges
  • Scoop out any floating pondweed and algae from pools and water features
  • Keep mowing lawns regularly, but raise the cutting height to leave the grass longer during dry weather
  • Water hanging baskets and patio containers daily, in the morning or evening
  • Deadhead bedding plants, sweet peas and annuals every few days to encourage more flowers
  • Set up an automatic watering system to look after greenhouse crops, pots and baskets if you're going on holiday
  • Make your own liquid feed from comfrey plants
  • Apply tomato feed fortnightly to crops in pots and growing bags, such as tomatoes and chillies, to encourage fruiting
  • Trim lavender after flowering to keep plants compact and bushy, but avoid cutting into old wood
  • Be on the lookout for developing pest problems and take action straight away

Trim conifers to maintain an even shape.

House plants

  • Feed houseplants once a week with liquid fertiliser, continuing through to autumn
  • Water your house plants more regularly as the temperatures warm and light levels increase, check the soil before watering. Take a look at our guide to watering house plants
  • Repot any houseplants that have become top heavy or pot bound into larger containers
  • Ensure house plants are not getting scorched by summer sunshine. Either move further from the window or choose house plants that will thrive in a sunny spot
  • Some house plants, like snake plants, are particularly prone to collecting dust on their leaves. So be sure to give these a wipe regularly
  • Put houseplants outside for the summer in a warm, sheltered spot to enjoy the fresh air and extra light
  • Take leaf cuttings from houseplants, including African violets, begonias and Cape primroses
  • Check your house plants for pests like aphids, scale insects, thrips and mealybugs
  • Take large-leaved houseplants into the garden and hose them down to clean off accumulated dust

For more house plant advice and inspiration visit our Growing and caring for house plants page

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Gardeners' World December 2025
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