IDEAL GREENHOUSE TEMPERATURE

The ideal temperatures to maintain inside your greenhouse will be dictated by what plants you have inside.

From over wintering tropical to starting seeds, remember all plants and seeds have preferred growing and germination requirements. This specific information is readily available at your local garden center and in numerous publications  -  Ask your local nurseryman for advice.

HEATING

The most effective way to heat your greenhouse is with a small ceramic heater. There are numerous models on the market, however we recommend you look for a ceramic heater with the following features:

• Automatic overheat shut off.

• Thermostat control. Allows you to set your desired temp, heater will automatically turn off and on to maintain your set temperature.

• Humidity sensor. Reads % of humidity in the air.

Heaters of this type are readily available at your local stores.

A large thermal mass, usually water or rock can be placed in your greenhouse to absorb and store heat during the day. At night this stored heat is released, warming your greenhouse.

A 55-gallon drum of water works well in the walk in style greenhouses. Placing a heating pad beneath the drum will generate additional warmth.

Adjusting the vent openings will change the inside temperature reading.

Always use extreme caution when using electrical devices. Keep away from water in case of electrical shock or fire.

COOLING

To lower inside temperature of your greenhouse, open screened vents and doors and attach shade cloth. A fan may also be used.

VENTILATION

It is essential to ensure good air circulation and ventilation year round. Stagnant air and or excessive humidity levels may result in fungus and disease, which can damage your plants.

FALL: Start heating system; ventilate night and day; remove shade cover; keep soil on the dry side; move tender tropical plants into greenhouse for over wintering.

A new garden season starts during the cold brisk days of autumn, but light is at a premium then for there are many cloudy days and the arc of the sun is very low. At this time, plants tend to make soft growth that is susceptible to mildew. Good air circulation is necessary to keep them healthy and disease free.

Turn the heat on just as nights become cool (below 40º F), and for short periods when days are damp. Keep vents open throughout the day.

Although this may seem like a waste of fuel, air circulation is important overnight. In some areas where damp weather prevails, fan heaters are preferable to ceramic as they provide greater air movement. Don’t forget to water!

Prepare clean pots, seed flats, and fresh soil for the greenhouse. Winter gardening is much more pleasant and productive when supplies are ready for use.

Fall is also a great time to start a new compost heap for spring planting.

The warm fall rains provide the moisture needed, and freezing and thawing throughout the winter do wonders for soil structure.

WINTER: Avoid drafts, sudden changes in temperature, or dry, burned out air.

Plants, like people, can’t thrive in poor atmospheric conditions.

In bright cold weather, it is easy to keep air fresh. Then the greenhouse traps more than enough heat from the sun, even though it may be freezing outside. During sunny days, open side vents 1 inch and/or roll down one door 1 inch from top.

In the event of very windy weather, close vents and doors on the windward side. Seal completely during heavy snowfall and storms. Keep roof clear of snow.

On cold nights, artificial heat keeps air in motion. Leave only a small crack opening in door or vent. During long spells of cloudy weather or freezing cold, you will need to use artificial heat to maintain your ideal temperature. Placing several pails of water inside your greenhouse can raise humidity. Remember to water!

SPRING: Increase temperature; start feeding schedule; maintain high humidity; attach shade cover.

As days become longer and sunlight gets more intense, growth will be noticeably faster and flowering more profuse. Water daily, as required, and maintain a regular schedule of feeding. Hose down floor every morning to make up for evaporation, and to increase humidity. Continue to heat at night if temperatures fall below 60º F.

Daytime temperatures may run up to 85º F or more by the suns heat although all vents and doors are open. This will not have a harmful effect. Attach shade cover just as soon as foliage starts to turn light green and shows signs of wilting under midday sun.

Keep an eye on your local minimum temps to determine when to discontinue night heating. Move/transplant your plants outdoors after danger of last frost for your zone has past.

SUMMER: Most plants can be left in the greenhouse for they are unaffected by high temperatures if sufficient moisture, shade and humidity are maintained. Leave vents and doors open 24 hours. Summer is also a great time for propagating cuttings. A great way to multiply your favorite plants.

Your Greenhouse makes a great storage shed for garden tools, and a convenient shelter for hanging baskets and potted plants during summer storms.