In The Greenhouse This October

🌡️ 1. Keep an eye on greenhouse temperatures

October nights can get surprisingly cold, even when the days are mild.

• Check greenhouse temperatures with a minimum–maximum thermometer.

• Move tender plants, such as begonias, pelargoniums and fuchsias, inside before the first frost.

• Insulate the greenhouse with horticultural bubble wrap if you plan to overwinter plants.

• Use a greenhouse heater with a thermostat if you need frost protection.

Tip: Group pots together to help protect roots from sudden temperature changes.

🥬 2. Sow winter salads and vegetables

Make the most of your greenhouse by growing fresh produce throughout autumn and winter.

• 🥬 Sow winter lettuce varieties for leaves over the colder months.

• 🌱 Sow lamb’s lettuce, rocket and spinach in trays or containers.

• 🌿 Try coriander and parsley in pots for fresh herbs.

• 🧅 Plant pots of spring onions for harvesting when needed.

Keep seedlings in the brightest part of the greenhouse.

🌺 3. Bring tender plants in for winter

October is the time to give frost-sensitive plants a safe place for winter.

• Bring in pelargoniums, fuchsias, begonias and other tender plants.

• Move citrus trees and tender potted plants into a frost-free greenhouse.

• Remove dead flowers, yellow leaves and any diseased foliage.

• Check plants carefully for aphids, whitefly and other pests before bringing them inside.

Water sparingly through winter, allowing the compost to dry slightly between waterings for plants that are resting.

🧹 4. Give your greenhouse a good autumn clean

A clean greenhouse allows more light in during the darker months and helps reduce pests and diseases.

• Wash the glass inside and out to maximise winter sunlight.

• Clear away old compost, fallen leaves and dead plant material.

• Clean benches, staging, pots and seed trays.

• Remove weeds and check corners for slugs and snails.

Use a suitable greenhouse cleaning product according to its instructions, and rinse surfaces before returning plants.

💨 5. Ventilate on mild, sunny days

Even in October, greenhouses can become warm and humid during the day.

• Open doors and vents on mild days to allow fresh air to circulate.

• Close them before temperatures fall in the late afternoon.

• Avoid leaving plants sitting in damp, stagnant air.

• Water in the morning so foliage and surfaces have time to dry.

Good ventilation helps reduce the risk of grey mould (botrytis), particularly on overwintering plants.

🌱 6. Take cuttings and save seeds

October is a useful month for making next year’s garden more affordable.

• Take cuttings from healthy pelargoniums and other suitable tender plants.

• Collect ripe seeds from flowers such as marigolds, cosmos and calendula.

• Label and store seeds in paper envelopes in a cool, dry place.

• Pot up rooted cuttings and keep them somewhere bright and frost-free.

Choose healthy, pest-free parent plants and use clean pots and fresh compost.

🪴 7. Prepare pots and equipment for winter

• Empty and clean pots that are no longer needed.

• Check heaters, thermometers and automatic vent openers.

• Repair broken glass and check that doors and vents close properly.

• Keep water containers and hoses protected from frost.

Make sure electrical heaters are suitable for greenhouse use and safely installed.