August is one of the busiest months in the greenhouse. With high temperatures, rapid growth and abundant harvests, regular care will keep plants healthy and productive.
Here are the top greenhouse jobs for August:
🍅Harvest crops regularly
Pick fruit little and often to encourage more production.
- Tomatoes
- Cucumbers
- Peppers
- Chillies
- Aubergines
Don’t allow overripe fruit to remain on the plant, as it slows further cropping.
✂️Keep tomato plants under control
August is the time to focus the plant’s energy on ripening fruit.
- Remove side shoots from cordon tomatoes.
- Tie in tall stems.
- Remove lower yellowing leaves to improve airflow.
- Towards the end of the month, pinch out the growing tip once 5–6 trusses have formed.
💧Water consistently
Greenhouses dry out quickly in summer.
- Water early in the morning.
- Check pots every day during hot weather.
- Water thoroughly rather than little and often.
Avoid letting compost dry out completely, especially for tomatoes and cucumbers.
🌿Feed hungry plants
Continue feeding:
- Tomatoes with a high-potash tomato fertiliser.
- Peppers, chillies and aubergines weekly.
- Cucumbers with a suitable liquid feed.
Regular feeding keeps crops flowering and fruiting well.
🌬️Ventilate every day
Heat can quickly build up inside a greenhouse.
- Open roof vents and doors each morning.
- Leave vents open overnight if temperatures remain warm.
- Improve air circulation to reduce fungal diseases.
On very hot days, greenhouse temperatures can easily exceed 35°C.
🌞Provide shade during heatwaves
If the greenhouse becomes excessively hot:
- Use shade netting or greenhouse shading paint.
- Damp down paths to increase humidity and lower temperatures.
- Protect young plants from scorching.
🐞Watch for pests
Warm conditions encourage:
- Whitefly
- Aphids
- Red spider mites
- Thrips
Inspect plants every few days, especially the undersides of leaves, and deal with infestations promptly.
🍂Remove dead leaves and old crops
Clear away:
- Yellowing leaves.
- Diseased foliage.
- Finished plants.
Good hygiene improves airflow and helps prevent fungal diseases.
🌱Sow crops for autumn and winter
There’s still time to sow:
- Winter lettuce
- Spinach
- Rocket
- Spring cabbage (in trays)
- Oriental leaves
- Herbs for indoor growing
Warm greenhouse conditions help seeds germinate quickly.
🌸Prepare for the seasons ahead
As some summer crops finish:
- Clean empty pots and trays.
- Plan space for autumn salads.
- Check heaters or insulation if you intend to overwinter tender plants.
🌼 Bonus tip: Help pollination
Tomatoes, peppers and aubergines benefit from a little help.
- Gently tap tomato flower trusses around midday.
- Shake flowering plants lightly to release pollen.
- Keep vents open so pollinating insects can enter whenever possible.
With regular watering, feeding, ventilation and harvesting, your greenhouse should continue producing abundant crops well into autumn while staying healthy and productive.
