Reset & begin

Often treated as a fresh planning point for sowing, organising and starting a new monthly cycle.

Build & tend

Traditionally linked with active above-ground growth, transplanting and care of leafy or fruiting crops.

Observe & harvest

A memorable point for checking maturity, harvesting and assessing plant health.

Maintain & clear

Commonly used for root crops, pruning, soil work, cleaning and preparation.

January

Plan the year, inspect the greenhouse and resist sowing too much too soon

January is primarily a planning month for most UK gardeners. Around the New Moon, review seed stocks, decide what will earn valuable greenhouse space and map out sowing successions. A few long-season crops can be started with enough warmth and supplementary light, but early sowing is only useful if you can keep seedlings strong until planting time.

During the waning part of the month, turn to practical maintenance. Clean glazing, check gutters and sliding doors, inspect vents and remove old plant debris. An unheated greenhouse can protect hardy crops, but it can still freeze. The main winter challenge is often damp rather than growth, so ventilate on suitable days and avoid leaving compost unnecessarily wet.

February

Increasing light makes early propagation more realistic

February brings noticeably longer days. If you follow lunar timing, the waxing Moon can be used to organise early sowings of chillies, peppers and other slow crops, provided you have good light and stable warmth. Hardy salads can also become worthwhile in protected conditions.

The Last Quarter is a useful reminder to prepare before the March rush. Wash trays, organise labels, check compost supplies and make sure greenhouse ventilation will open freely on bright days. Southern counties may move earlier than upland or northern locations, so follow your local conditions rather than a national average.

March

Propagation accelerates and greenhouse space becomes valuable

March is one of the busiest sowing months. Tomatoes, herbs, flowers and many summer crops can be started during the waxing part of the lunar cycle if that suits your routine. Seedlings quickly move from small modules to larger pots, so plan the next stage before every bench is full.

During the waning Moon, prepare beds, refresh compost, clean paths and test irrigation. A bright March day can make a greenhouse surprisingly warm while the night remains cold. Scotland and northern England may still be several weeks behind sheltered southern sites. The greenhouse is a buffer, not a promise that frost has finished.

April

Strong sunshine, fast growth and unpredictable cold snaps

April is ideal for using the lunar cycle as an organisational tool. The waxing period can be used for further sowing, potting on and gradual hardening off. Give seedlings enough room for air and light rather than crowding them simply because the greenhouse appears full of useful space.

Around the Full Moon, check ventilation carefully. On clear days, a closed greenhouse can overheat before the outdoor air feels warm. The waning period is a good time for bed preparation and tidying. Tender plants should still be protected when cold nights are forecast; a favourable Moon date does not cancel a frost warning.

May

Main planting season arrives, but night temperature still matters

May is when many British gardeners move tomatoes, cucumbers and peppers into their long-term greenhouse positions. Traditional lunar gardeners may favour the waxing phase for these above-ground crops. Use it as a planning window, but wait until the greenhouse environment is genuinely warm enough.

Once crops are planted, daily management becomes more important than sowing dates. Tie in tomatoes, train cucumbers, check watering and open vents early on sunny days. During the waning Moon, remove dead or damaged material and keep paths clear. The success of a greenhouse in May is often determined by airflow and consistent care.

June

Long days bring rapid growth and high water demand

June provides excellent light across the UK. The waxing Moon can be used to schedule successional herbs and salads while main greenhouse crops grow quickly. Tomatoes and cucumbers now need frequent attention, and containers may dry much faster than they did only a few weeks earlier.

Around the Full Moon, make plant-health checks part of your routine. Look for pests, leaf stress and overcrowding. On hot spells, ventilation and shading may be essential. The waning period is useful for pruning, cleaning and clearing unnecessary growth. Water according to the compost and weather, never according to a lunar rule.

July

Harvest regularly and manage heat before it becomes stress

July is an abundant greenhouse month. Use the lunar calendar to create regular harvest checkpoints for tomatoes, cucumbers, herbs and other productive crops. Picking little and often keeps plants manageable and ensures fruit is not left to become overripe.

Heat can build quickly under glass even in an otherwise moderate British summer. Keep vents and doors open when conditions allow, check containers morning and evening during hot spells and prepare autumn sowings in any space that becomes free. The waning Moon is a useful prompt for removing diseased leaves and cleaning empty areas.

August

High summer harvest meets the first serious autumn planning

August remains productive, yet declining day length is already noticeable. In 2027 the month contains two New Moons in the local calendar, giving lunar gardeners two obvious planning markers. Use them to think about autumn salads, spinach, herbs and how long you want main summer crops to remain.

Continue to ventilate well and keep tomato foliage from becoming excessively dense. In northern areas, nights may cool earlier than in the South East. As crops finish, clear and clean small zones rather than waiting for the whole greenhouse to become empty at once. That makes autumn transition much easier.

September

Lower light makes humidity control increasingly important

September can still produce excellent tomatoes and peppers, particularly in a sheltered greenhouse. The waxing phase can be used to organise quick salads and herbs. The Full Moon provides a useful reminder to assess ripeness and plant health before cooler nights begin slowing growth.

Ventilation remains important even when the air feels cool. Condensation lasts longer and damp foliage becomes more problematic. Use the waning phase for clearing spent crops and preparing beds for winter salads or other hardy choices. Scotland and upland gardens may make this transition well before the south coast.

October

Use protection wisely and focus on crops that suit low light

October is about extending the season rather than pretending summer continues. Hardy salads and established crops can still benefit from greenhouse protection, but new heat-loving sowings are unrealistic. Use the lunar calendar to organise harvesting and the gradual transition to winter use.

The waning Moon is a good reminder for a thorough clean-up. Remove spent tomato and cucumber plants, clear fallen leaves and check gutters before autumn storms. If winter crops remain, keep ventilation available and water cautiously. Lower light means lower water use.

November

A quiet month for observation, winter crops and maintenance

November growth is slow in an unheated British greenhouse. Use the lunar phases as simple inspection dates rather than ambitious sowing windows. Hardy leaves may continue, but they need less water and can suffer if the atmosphere remains permanently damp.

Use dry weather for repairs, cleaning and checking doors, vents and fixings. Remove organic debris that can shelter pests. A tidy November greenhouse is easier to manage through winter and far easier to restart when light returns.

December

Review the season and design a better growing plan for next year

December is ideal for reflecting on what actually worked. Which crops earned their space, where did the path become too narrow, which varieties performed well? Around the New Moon, turn these observations into a realistic plan for 2028 rather than repeating the same crowded layout.

Inspect the greenhouse after storms and clear gutters or debris. Ventilate on suitable dry days and avoid unnecessary watering. The most useful role of the Moon calendar at this point is regularity: it gives you a reason to look carefully at the structure and the plants even during the quietest weeks.

Lettuce, spinach & herbs

Traditionally linked with the waxing Moon. In practice, cool temperatures and adequate light make the biggest difference.

Tomatoes, cucumbers & peppers

Use phases as reminders for sowing, potting on, training and harvesting. Warmth, airflow and root space determine performance.

Radish, beetroot & carrots

Often associated with the waning Moon. Loose soil, moisture and correct spacing matter much more than phase.

Colour, scent & pollinators

Stagger sowings so the greenhouse does not receive one large wave of plants at the same time.