Greenhouse Calendar: What to Do in Your Greenhouse Each Month
A greenhouse allows gardeners to extend the growing season, protect crops from harsh weather, and enjoy fresh harvests throughout much of the year.
While tasks vary depending on your climate and greenhouse type, every month offers opportunities for planting, maintenance, harvesting, and planning.
Use this greenhouse calendar as a year-round overview and click through to the monthly guides for detailed growing advice.
January greenhouse calendar
January: Planning and Early Sowing. January is often the coldest month, making greenhouse insulation and temperature management top priorities. It is an excellent time to plan the growing season, organize seeds, clean equipment, and start sowing slow-growing crops such as onions, leeks, and certain herbs. Regular monitoring for frost damage and excess humidity helps keep plants healthy through winter.
February greenhouse calendar
February: Preparing for Spring. As daylight hours gradually increase, greenhouse activity begins to pick up. Gardeners can start sowing early vegetables, including lettuce, spinach, and brassicas, while continuing winter maintenance tasks. Proper ventilation remains important to prevent fungal diseases during fluctuating temperatures.
March greenhouse calendar
March: The Growing Season Begins. March marks the beginning of active spring gardening in many regions. Seed trays quickly fill with tomatoes, peppers, cucumbers, and flowers destined for later transplanting. Increased sunlight encourages rapid growth, making watering, feeding, and ventilation more important than during the winter months.
April greenhouse calendar
April: Rapid Growth and Transplanting. Warmer temperatures create ideal conditions for vigorous plant development. Seedlings require potting on, hardening off, and careful monitoring to avoid overcrowding. Many gardeners begin planting greenhouse crops into their final growing positions while preparing for the busy summer season ahead.
May greenhouse calendar
May: Peak Planting Time! May is one of the busiest months in the greenhouse. Tender crops such as tomatoes, peppers, cucumbers, melons, and basil can be planted out in many areas. Fast growth demands regular watering, feeding, training, and pest monitoring to ensure plants establish successfully.
June greenhouse calendar
June: Managing Summer Growth. With longer days and rising temperatures, greenhouse plants often grow at remarkable speed. Ventilation, shading, and irrigation become essential to prevent heat stress. Gardeners spend much of the month pruning, training vines, and supporting heavy fruiting crops.
July greenhouse calendar
July: Harvest Season Arrives. July rewards greenhouse growers with abundant harvests of tomatoes, cucumbers, peppers, herbs, and other warm-season crops. Regular harvesting encourages continued production while ongoing maintenance helps manage pests, diseases, and excessive summer heat.
August greenhouse calendar
August: Maintaining Productivity. Many greenhouse crops remain highly productive throughout August. Consistent feeding and watering help sustain yields, while gardeners can begin sowing autumn and winter vegetables for later harvests. Attention to airflow remains critical during periods of high humidity.
September greenhouse calendar
September: Transitioning to Autumn. As temperatures begin to cool, greenhouse priorities shift toward extending the harvest season and preparing for colder weather. Late-summer crops continue producing while new sowings of leafy greens, spinach, and winter salads help ensure future harvests.
October greenhouse calendar
October: Extending the Season. October is an important month for protecting crops from the first frosts. Greenhouses provide valuable shelter for late harvests and newly planted winter vegetables. Cleaning, organizing, and preparing heating or insulation systems now can prevent problems later in the season.
November greenhouse calendar
November: Winter Preparation. Plant growth slows considerably as daylight decreases. Gardeners focus on harvesting remaining crops, maintaining winter vegetables, and reducing disease risks through careful ventilation. It is also an ideal time for greenhouse repairs and deep cleaning projects.
December greenhouse calendar
December: Reflection and Maintenance. December is generally the quietest greenhouse month. While hardy greens and overwintering crops may still be harvested, much of the focus shifts toward maintenance, planning, and preparation for the coming year. Reviewing successes and challenges helps gardeners improve next season’s results.
Growing Successfully All Year Round
Your greenhouse creates opportunities for year-round gardening, but remember that your success depends on understanding seasonal tasks and changing environmental conditions.
By following a monthly greenhouse calendar, you too can maximize harvests, maintain healthy plants, and make the most of every growing season, even you’re just a beginner gardener 🙂